Date   

Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

Bernard Harper
 
Edited

Thank you Jack,  I had no idea so much of Ardipethicus had been found and studied in such depth. A question to accompany "human" gait and gape is the best molecular dating for our ancestors divergence from the LCA.  IMO the 24 chromosomes apes and monkeys share links their gait and gape as much as our 23 chromosomes link our ancestors to us. It has always made perfect sense to me to lump together all fossils with our gait and gape as (most likely) also having 23 chromosomes. Many references I have seen date this change at 4.5 to 6 Myr., which is right on the dates for the key fossils.  Maybe that infamous genomics company 23&Me should be also thought of as  23&Sea? Or am I barking up the wrong tree?? 

Bernie


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

Gareth Morgan
 

So, you suggest that, about 5 million (or 2 million) years ago,  semi-bipedal apes on the African shore developed subcutaneaous fat, large brain, bipedalism, multi-pyramidal kidneys, prolific eccrine glands and Pacinian corpuscles, menopause, adducted hallux, vernix, rotated pectoral muscles, loss of estrus, naked skin, multiple genes for amylase, long head hair, hymen, psychic tears, acne, diminished apocrine glands, aural exostoses, low body temperature, shortened muzzle, and canine teeth, beards, huge skeletal changes in the pelvis and skull, improved breath holding, speech and tool use... all at the same time, due to a single occurrence of climate change... and then... nothing... (other than some slight variations for different water temperatures and depths)...? Climatic events since then, including scores of ice ages and interglacials, and widespread extinctions, have had no effect whatsoever, other than making us less and less well adapted to water. 


Okay. That was the Hardy/Morgan proposition, more or less. I think Robert Foley was the first to point out that the order in which these changes actually occurred, as far as we know, indicated gradually increasing aquaticism, not less, though the article doesn't seem to be available any more. http://www.pendlynxhare.com/249/Aquatic%20Ape%20Hypoth/Constraining%20the%20AAH.pdf   On that basis he rejected AAT.

I don't think I'm being controversial in suggesting that we evolved in a process combining phyletic gradualism and punctuated equilibrium -- like everything else  https://en.wikipedia.org/wiki/Punctuated_equilibrium , rather than in one gigantic Lamarckian total redesign.

Let's have a look at some of that comparative anatomy...

Smaller lungs than Neanderthal. Gorillas have a much larger thorax than either. Does that make them more aquatic? 



Longer legs than Neanderthal/erectus. See above. Does that make us less aquatic than a gorilla?
Lighter bones. All the better for swimming. Chimps drop straight to the bottom of the pool. Does that make them more aquatic than us?
More globular crania. Purely to balance the skull on the spine for bipedalism. Those macaques swim perfectly well with elongated skulls.
Flatter faces. Again, bipedalism. Nothing to do with water. Certainly no handicap in water though. More streamlined.
Smaller brains. Discussed previously. Evolutionary changes that cause certain death to mother and child tend not to continue along the same lines.
Probably less fat. Sorry. Can't discuss probablies.

That's all for now. Will reread and maybe write some more.

Thank you very much for the fetal chimp foot refs. This is very important though, and when so much was written about hair tracts and water flow, when hair tracts actually point in the opposite direction, I'll have to wait for photographic x-ray or fetal autopsy evidence before I can accept it. I appreciate that it would be very significant for showing that "chimps evolved from us" as Elaine put it. 

G.



From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Wednesday, April 20, 2022 7:58 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?
 

Hi G.

 

Actually, I’m tempted to think that the most aquatic stage was pre-erectus as H. erectus had acquired most of their aquatic features by the time they appeared on the scene, c. 2 Ma, so clearly they were considerably aquatic before then. (IMO, this would be during our Red Sea, Arabian Peninsula, isolation/speciation phase, c.5 – 2.5 Ma during the Pliocene – just like Elaine always said – and the environmental and climatic conditions would support that they would have spent most of their time in the sea, but we have no fossil evidence so it’s just a hypothesis!)

 

There were many different versions of H. erectus and they existed for a long time. E.g., Turkana boy (H. ergaster/Africa) was more gracile and was found by a lake, whereas H. erectus (sensu stricto) / Javicus occupied coastal basins and river plains in Indonesia and was more robust, so probably dived in the sea more. But Meganthropus had even thicker bones than H. erectus, and was older (I’m still researching this – they’re a bit of an enigma). I’m not sure if Neanderthals were more or less aquatic than H.e, probably to a similar extent, but H.n dived in colder waters and probably had greater calorie requirements, so there was quite a lot different about their lifestyles.

 

F.

 

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Wednesday, April 20, 2022 7:34 PM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Great stuff, Francesca. Good points, well put. Will reply in full shortly. Meanwhile, for clarity, do you disagree with the proposition that "Homo erectus (sensu stricto) [was] the most aquatically adapted hominin", and are you saying that Neanderthal was ?

 

Thanks.

 

G.

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Wednesday, April 20, 2022 6:26 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

G: How do you determine tree climbing skills? In any case Australopiths were less aquatic than us and apparently are not considered ancestral to us anyway. This is all also predicated on the view that bipedalism is an aquatic adaptation. I don't think that was why it evolved originally.

 

F: “Many of the same features seen in australopithecines in Africa that are often cited as an indication of a species belonging to the human lineage, such as an anteriorly situated foramen magnum, short but broad ilia, relatively small canines, etc., are also found in many of the fossil apes from Europe (Wood & Harrison, 2011). Furthermore, if a taxon displays features both for bipedalism and arboreal climbing, it is traditionally understood to imply that the species is somehow transitional between a more arboreal earlier form and a later more terrestrial form, when it could just as easily have been going the other way. Evidence shows that some late australopithecines, such as Australopithecus sediba from 1.98 Ma, were more arboreal than earlier australopithecines, such as Australopithecus afarensis (Rein, et al., 2017*). The same could be said regarding brain sizes as we quite often see that the later australopithecines had smaller cranial capacities than earlier fossils. For example, from East Africa, the younger Paranthropus aethiopicus (2.7-2.3 Ma) had a cranium (c. 410 cc) falling within the range of the much older A. afarensis (c. 375-550 cc) at 3.9-2.9 Ma; while in South Africa, at 1. 98 Ma, A. sediba’s cranium was 420-450 cc and therefore smaller than A. prometheus’s cranium (500-520 cc) was already at 3.67 Ma. Although we are not claiming a direct line through any of these species, there is no clear trend showing that australopithecines were becoming more Homo-like over time.”

“Researchers compared A. prometheus’s shoulder to apes, hominins and humans and found that Little Foot was adapted to living partially in the trees and partially on the ground. As well as relatively long legs and limited bipedal foot morphology, it had a long, curved clavicle and dorsally positioned scapula with a high ridge to attach heavy muscles, ideal for supporting its weight below branch, more similar to that seen in arboreal apes, such as chimpanzees. They concluded that “the arm of our ancestors at 3.67 Ma was still (my emphasis) being used to bear substantial weight during arboreal movements in trees, for climbing or hanging beneath branches.” [i] The assumption here is that this is a retained feature from a more primitive ancestor, rather than the expression of an earlier adaptation as a result of returning to the trees.”

“In a recent paper, scientists revealed the results of a study in which they compared the heel bones (calcanei) of humans, extant apes and various hominin fossils. They found that earlier Australopithecus species, such as Lucy’s, had a heelbone more similar to humans than apes, better to support their weight on two legs, while later apiths had more ape-like heelbones, suggesting a reversal over time from bipedalism to arborealism.[ii] Other researchers studying hominin foot evolution have suggested that the similarities between A.afarensis’ feet and human feet might imply that they both “descend from a common ancestor with a similarly derived foot” and that “the large calcaneal tuber (heel bone) is obtained in developmentally different ways in A. afarensis and in modern humans.”[iii] In other words, homoplasy.”

 

*Adaptation to suspensory locomotion in Australopithecus sediba

https://www.sciencedirect.com/science/article/abs/pii/S0047248416302743

 

(I’m not claiming bipedalism is strictly aquatic, although I do think it emerged out of orthograde apes wading in wetlands in the first instance. And I don’t believe australopithecines are ancestral to us, but ancestral to the African apes, which is the point I’m making here).

 

There is evidence that Pan’s feet were once like ours

 

G: I have been looking long and hard and found nothing. This is quite important. I won't take it on trust. All the evidence (in utero, for instance) that I can find says the opposite.

 

F: Marc has always referenced C. S. Coon for this, but I haven’t been able to find the direct source. However, in another paper I found this (with no reference).

 

“The marked abductability of the chimpanzee hallux is probably a derived condition within the human/African ape clade. Indeed, embryos of chimpanzees have an adducted hallux suggesting that relative adduction could be the LCA primitive condition…”
Meldrum, Jeff & Sarmiento, Esteban. (2018). Comments on possible Miocene hominin footprints. Proceedings of the Geologists' Association. 129. 10.1016/j.pgeola.2018.05.006.

 

Also, Schultz, 1925 noted – although he doesn’t say at what stage this happens in chimpanzees…


“In all primates the great toe is found to branch from the sole, just at the base of the second toe, in very early growth stages. This embryonic position is retained throughout life in man, whereas in all other primates the place of attachment of the great toe shifts proximally, similar to the ontogenetic shifting in the attachment of the thumb to the palm from the base of the index finger to a place nearer the wrist. In the gorilla this shifting of the hallux is least pronounced of any of the apes, whereas it is most extreme in the orang, a greater difference existing in this respect between the latter and gorilla than between gorilla and man (fig. 16). Other propor tions on the foot lead to similar conclusions…”

https://www.jstor.org/stable/pdf/24527371.pdf

 

G: If there have been no reversals, then in what possible sense can we be less aquatic than we used to be?

 

F: There are many ways. Read the paragraph I wrote further down about ‘reduction’ of features (smaller lungs, etc.), and this is only from fossil evidence, which is very limited, and based on comparative anatomy with other species, so we can’t really know what other features we may have fully lost. Maybe we did have webbing between our fingers & toes… (!!)

 

I’m talking about Pan (chimps) not Homo.

 

G: The premise I thought we were discussing was the one about whether early Homo was more or less aquatic than us. Whether chimps reverted or not really doesn't have any bearing.

 

F: Yes, we were, but earlier we were also talking about climate and how it instigated evolutionary changes. I included a small two-line reference to Panins to suggest why the australopithecines may have become more arboreal as the African wetlands dried up.

 

Thick brow ridges are great if you dive, browse and forage underwater... to push water away from the eyes

G: This is simply not true. I've mentioned katabatic flow to you before. When any fluid flows over a ridge it drives forcibly down the other side. Into your eyes in other words if it is a brow ridge.

 

F: I’m not convinced by this but clearly more research is needed. I suppose it is testable. The example you give is based on air, not water, and presumes a straight directional flow over the ridge. I believe the brows on a hominin, face down in water, would divert the flow of water away to the sides of the face. Maybe it’s not so much to do with swimming but even surfacing regularly to breathe. With a flat face and no brows the water would just pour straight down into your gasping mouth. In general, our brows are thought to be useful in diverting sweat from flowing into our eyes, so the same principle is true, but just with more water, more regularly.

 

And how do you get “more aquatic” Asian people? Some are, of course, if you’re thinking of Moken, etc. or Japanese pearl divers, but can we say Asians are more aquatic. We are all still H.sapiens.

 

Neanderthals were more aquatic than Homo sapiens. 

 

G: A bigger brain, I happily concede. However all the known big headed humanoids became extinct -- proto-Innuit, Boskop man, "coneheads", Neanderthals.... The fact that fewer and fewer females appeared over time suggests that heads became too big to pass through the birth canal, killing the mothers in childbirth. We are about on the sustainable limit, partly thanks to Caesarian sections. A reality that anthropologists manage to ignore, preferring to focus on how jolly intelligent they think they are.

 

F: Is that a fact? Do you have a reference? We don’t know why Neanderthals went extinct. Many reasons are proposed.

 

G: Homo erectus had a tiny brain anyway. Are we to conclude then that he was less aquatic than us? Makes sense. We just can't have it both ways.

 

F: Homo erectus’ brain capacity, with an average of 950cc, [iv] ranged from 550cc in some early samples, to 1251 cc,[v] which is close to that found in modern humans. (I personally believe that brain size increase is a result of marine-chain based nutrients + cold water, which explains the size increase as the climate got cooler. Neanderthals with the largest brains, swam in the cold waters of the Atlantic. Only a more aquatic species would do that regularly, don’t you think?).

 

G: Big, heavy bones are really a huge handicap in the water if you think about it. Bad for swimming and floating. Good, on the way down, for diving. Coming up...  good for drowning. Manageable in sea water. Big problem in fresh. Neanderthal was robust because, like Australopithecus robustus, he was designed to live mostly on land and struggled to make a living in the water, not yet having our perfect neutral buoyancy and other modern refinements. Frequently fractured his skull diving in, apparently.

 

F: “In the animal kingdom, good runners tend to be gracile, or lightly built, (e.g., cheetahs, antelopes, horses, greyhounds), and even floating semi-aquatic animals such as ducks have light bones. Conversely, dense, heavy bones tend to be brittle and not suitable for fast or sustained terrestrial locomotion. As noted by Alexandra Houssaye, et al, in their study of amniote bone microanatomy regarding thick cortical bones: “These rather well-known specializations are considered incompatible with a terrestrial locomotion and generally do not occur (or incipiently so) in terrestrial taxa… or even in most semi-aquatic taxa.” In contrast, bone mass increase is found “in almost all highly or exclusively aquatic amniotes foraging below the water surface.[vi]

 

Seems quite clear to me that both erectus and Neanderthals, with their heavier, more robust bones, were better suited to shallow diving and totally incompatible with running. And possibly why women have more fat then men (males may have been deeper divers) and why women gain fat & lose bone density after menopause when they have to be floating around at the surface with the grandkids.

 

G: As you know I consider the most aquatic hominin ever was Strandlooper (Boskop man) -- extinct for only a few hundred years or so. If you look at all the (aquatic) features that distinguish us from earlier ancestors, Strandlooper had them all, but very much more so. We know they were fully dependent on marine resources, because to find even a blade of grass they would have had to cross both the Kalahari and the Namib deserts, the latter having existed for over 50 million years, and you can see their shell middens from many miles away.. 

 

They were more gracile than us. "paper thin ribs" Their brains were a full 30% bigger than ours (forebrains + 50%). No brow ridge at all. Tiny teeth. Very prominent, sharp chin. Different in every way from the rugged Neanderthals. More aquatic....

 

F: I can’t comment on Strandloopers – I haven’t researched them yet. It sounds as though there are a mix of features. If they had gracile bones, they may have been surface swimmers rather than divers.

 

 just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. 

 

G: Precisely, then we obviously have more aquatic adaptations than any previous hominin who hadn't yet developed them. i.e we are the most aquatic (surviving) hominin.

 

F: Not losing a feature doesn’t mean it still serves its original function, especially if it is reduced. I repeat: we have smaller lungs, longer legs, lighter bones & shorter femora (better adapted to terrestrial locomotion than our ancestors), more globular crania, lower eyes, flatter faces (better when standing erect), smaller brains (less swimming in cold water, less seafood consumption, self-domestication-agriculture), we are probably less fat than Neanderthals (although they weren’t direct ancestors, we seem to have inherited our fat genes from them). Also, we cannot say that modern Homo sapiens – as a whole – is predominantly aquatic anymore. We retain some reduced aquatic features and tendencies. The whole point of the “Scars of Evolution” (E. Morgan) is that our scars are the remnants of a more aquatic past. Hardy and Morgan had it right. We were more aquatic in the past, but we can agree to disagree as everyone does here! 😊

 

QED.

 

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Tuesday, April 19, 2022 10:54 PM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

The climate I refer to from Miocene onwards is all supported by scientific research.

 

Yes. It's only the older stuff I decline to offer any opinions on.

 

 

There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel  

 

I have no problem with that.

 

 

 

 Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

 

Smaller, maybe. How do you determine tree climbing skills? In any case Australopiths were less aquatic than us and apparently are not considered ancestral to us anyway. This is all also predicated on the view that bipedalism is an aquatic adaptation. I don't think that was why it evolved originally.

 

There is evidence that Pan’s feet were once like ours

 

I have been looking long and hard and found nothing. This is quite important. I won't take it on trust. All the evidence (in utero, for instance) that I can find says the opposite.

 

 

 

I think you misunderstood me… there was only one reversal

 

Great. If there have been no reversals, then in what possible sense can we be less aquatic than we used to be?

 

 

I’m talking about Pan (chimps) not Homo.

 

The premise I thought we were discussing was the one about whether early Homo was more or less aquatic than us. Whether chimps reverted or not really doesn't have any bearing.

 

 

 

Thick brow ridges are great if you dive, browse and forage underwater... to push water away from the eyes

 

This is simply not true. I've mentioned katabatic flow to you before. When any fluid flows over a ridge it drives forcibly down the other side. Into your eyes in other words if it is a brow ridge. Here's a diagram of a "Chinook wind" to illustrate what happens.

 

 

"A 40- to 50-mph wind over the ridges and passes may reach speeds of 80 to 100 mph by the time the air reaches the foothills (on the other side)".

 

It therefore follows that losing the brow ridge makes for better underwater vision. The more aquatic Asian people have less of a brow ridge than westerners and modern Man has a more "streamlined" face than any previous ancestor. i.e. more aquatic.

 

 

 

Neanderthals were more aquatic than Homo sapiens. 

 

A bigger brain, I happily concede. However all the known big headed humanoids became extinct -- proto-Innuit, Boskop man, "coneheads", Neanderthals.... The fact that fewer and fewer females appeared over time suggests that heads became too big to pass through the birth canal, killing the mothers in childbirth. We are about on the sustainable limit, partly thanks to Caesarian sections. A reality that anthropologists manage to ignore, preferring to focus on how jolly intelligent they think they are.

 

Homo erectus had a tiny brain anyway. Are we to conclude then that he was less aquatic than us? Makes sense. We just can't have it both ways.

 

Big, heavy bones are really a huge handicap in the water if you think about it. Bad for swimming and floating. Good, on the way down, for diving. Coming up...  good for drowning. Manageable in sea water. Big problem in fresh. Neanderthal was robust because, like Australopithecus robustus, he was designed to live mostly on land and struggled to make a living in the water, not yet having our perfect neutral buoyancy and other modern refinements. Frequently fractured his skull diving in, apparently.

 

 

As you know I consider the most aquatic hominin ever was Strandlooper (Boskop man) -- extinct for only a few hundred years or so. If you look at all the (aquatic) features that distinguish us from earlier ancestors, Strandlooper had them all, but very much more so. We know they were fully dependent on marine resources, because to find even a blade of grass they would have had to cross both the Kalahari and the Namib deserts, the latter having existed for over 50 million years, and you can see their shell middens from many miles away.. 

 

They were more gracile than us. "paper thin ribs" Their brains were a full 30% bigger than ours (forebrains + 50%). No brow ridge at all. Tiny teeth. Very prominent, sharp chin. Different in every way from the rugged Neanderthals. More aquatic....

 

 

 just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. 

 

 

Precisely, then we obviously have more aquatic adaptations than any previous hominin who hadn't yet developed them. i.e we are the most aquatic (surviving) hominin.

 

QED.

 

G.

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 7:02 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Thanks, Gareth

Thanks, Francesca.

 

Would it be possible to reveal the source of this text

 

That would be me.  Email, subject "Second draft" about where when and how we became aquatic.

Ok, thanks. I’ll have another look for it.

 

 many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

Agreed. But they didn't spring up, fully formed overnight. They gradually improved, gradually increased in number and range of functions.

Agreed, that’s what I’ve been writing about.

 

I'm not making any guesses about what happened before the Miocene --  what the climate was like in some particular region, tectonic events, sea levels, vegetation, predators or the particular 'cause' of any specific change in physiology. For one thing I'm sure that none of these conditions remained unchanged for millions of years at any point, so too much of it is guesswork based on insufficient evidence. Almost anything could have happened somewhere at some point.

The climate I refer to from Miocene onwards is all supported by scientific research.

 

reversal from upright bipedalism towards arborealism

 

Not aware of any evidence for this "reversal". Not to say it couldn't or didn't happen, but if I ever knew of any evidence, I've forgotten.

There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel, from an already upright common ancestor, after splitting from a common ancestor. First they walked on 4 legs, then they walked on 2, then they walked on their knuckles.

Many of the australopithecines seem to become more arboreal over time, not less. Eg. Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

 

My only comments would be that, once we learned to throw, we were never able to brachiate again because of the change in orientation of our pectoral muscle.. Once we became bipedal, the loss of the divergent hallux meant we could never grasp a branch with our feet again. Not sure what kind of arborealism this would leave us. 

Humans didn’t become arboreal again, only Pan did. The point I’m trying to make is that the LCA was probably already a biped. After we split, the Pan line remained bipedal (wading, wetland foraging) for a while, but later, they returned to the forests, started climbing trees and walking on their knuckles when on the ground. There is evidence that Pan’s feet were once like ours (adducted halluces) but later their big toe moved round to the side and they could grasp branches again. (Pan foetus in utero).

 

 I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

We need to look at the other features that you consider reversals to see if any of them are aquatic features that we have lost since early Homo....

I think you misunderstood me… there was only one reversal I mentioned and that was in chimps…

 

You mention...

 

6 Ma: human-like foot morphology (loss of arborealism). -- Arborealism is definitely not aquatic.

That’s my point. We lost arboreal features because we became more aquatic. Or, because we became more aquatic, we lost arboreal climbing abilities.

 

5-2 Ma: Gradual reversal from upright bipedalism. -- Don't think I believe this (Open to persuasion. See above.) but anyway bipedalism is either not essentially aquatic, in which case it's irrelevant or it is, in which case we have become more aquatic (more upright), not less, since early Homo.

Yes, again, I think you’ve misunderstood me. Here I’m talking about Pan (chimps) not Homo. Reverse adaptations in evolution are more common even than first time adaptations. It happens all the time. It’s a result of gene expression. Once the gene exists, it can be switched on or off, according to need. That’s why snakes evolved legs, then lost them again. So did whales, etc. Chimp and human ancestors lost their fur, then chimps grew theirs again, but we didn’t. Early elephants lost their fur but woolly mammoths grew it back as they moved north. Some people are sometimes born with a tail, or webbing between their toes, because those genes still exist, even if silenced at the moment.

 

I think Homo is closer to the LCA in morphology than chimps. We haven’t changed as much as they have over the past 5-6 million years, and this is seen in their Y-chromosome. And most of those changes in chimps probably happened in the last million years or so, after they diverged from bonobos. Bonobos are more like us than chimps are (see picture attached).

 

2.0 Ma: Homo appears:  taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism, more sophisticated stone tool use, shellfish consumption. -- Other than the thick brow ridges (survival benefit not obvious to me) these all seem to be increases in aquatic adaptation.

Thick brow ridges are great if you dive, browse and forage underwater. Like a hooded nose, they act together to push water away from the eyes and nostrils as you move forward.
And yes, this is meant to demonstrate increases in aquatic adaptation. My point is, early Homo at 2 Ma was far more aquatic morphologically than H. sapiens is now.

 

300 ka to present: Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?) -- Again these seem to be evidence of a more aquatic lifestyle, not less.

Yes, Neanderthals were more aquatic than Homo sapiens. Again, that’s my point.

 

Which aquatic features do you think we have lost, then? What makes you think we are less well adapted to warm, cold, shallow, deep, clean, muddy, fresh or salt water than any of the less derived hominins? Your entire timeline seems perfectly to support my observation that aquatic adaptations have been a gradual, punctuated, cumulative process that has continued till today.

We haven’t fully lost any of those earlier adaptations (that we know of) but each is less pronounced. We have smaller thoraxes and reduced lung capacity compared to early Homo, as we don’t dive as much. We have lighter bones because we walk/run more, swim and dive less. We can’t see well underwater unless this skill is practised from childhood. We have less pronounced brow ridges for the same reason. We have rounder crania as we spend more time standing upright, whereas the more elongated crania of early Homo is better supported in a swimming, floating or diving position. We can swim and dive pretty well, for an ape, but not as well as erectus probably did. They may have been able to swim vast distances and dive to much deeper levels. They could probably hold their breath much longer than we can, or close to what professional / record holding divers can do now.

 

As your mum once wrote, just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. We would only lose it if keeping it was detrimental to our survival. We haven’t regrown our fur because we discovered clothes and central heating as an alternative means of keeping warm (and still get to go to the beach!) If we hadn’t, only the most hairy of us would survive in a colder climate to pass on our genes, so over time, our children would get hairier and hairier. We didn’t revert to quadrupedalism because by the time we became fully terrestrial again, our legs were much longer in relation to our arms and so the proportions were all wrong. Plus, we didn’t need to. By then we were quite comfortable moving around on 2 legs and using our forelimbs for other purposes. It’s served us quite well.

 

F.

G.

 

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 12:19 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Hi Gareth,

 

Would it be possible to reveal the source of this text, please? I’d like to read it.

 

I agree that climate has influenced anthropoid evolution at many stages and in different ways, although I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

If we look at the evidence, many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

[1st aquatic stage: Hominoidea]

30-25 Ma Climate: very hot, humid, subtropical forests; tectonic upheaval and rifting causing vast areas of East Africa to become flooded, creating forested islands in vast East African lakes.

25-20 Ma: orthograde body plan and modifications towards bipedal posture, suspensory adaptations of the wrist, hand, shoulders and arms, larger, wider thorax, loss of tail, etc.
20 – 14 Ma: gradual increase in size from small-bodied primates to large chimp sized apes

Some time between 25 Ma and 16 Ma: partial loss of pelage (great apes relative to macaques)

Overall increase in eccrine gland distribution (between OWMs and apes)

Probable reduction in olfactory ability

PNS

c. 18- 16 Ma Hylobatidae diverge

 

16-14 Ma: Climate: temperature decrease, reduced humidity & loss of biodiversity in Africa; increasing biodiversity, humid sub-tropical forests & vast bodies of water in Eurasia, land bridges between the two continents. Disappearance of most apes from Africa. Appearance of many ape species in Eurasia.

15 Ma: loss of uricase mutation and the ability to store sugars as fat

 

[Hominidae]

15-13 Ma: the ability to fashion stone tools

c. 15-14 Ma: Pongo diverges

14 Ma: plantigrade locomotion (quadrupedal)

12-11 Ma: loss of prognathism, robust jaws, postural bipedalism (wading)

11-9 Ma: Vallesian crisis causes the extinction of many apes (loss of forests, loss of edible fruits, spreading grasslands, seasonal food availability).

10-7 Ma: bipedal hominids roam the river valleys & great lakes of southern Europe & the Tethys-Med coasts.
Smaller, more thickly enamelled dentition – change of diet.

 

[Homininae]

10-6 Ma: terrestrial bipedalism develops

c. 10-8 Ma: gorilla divergence

7 Ma: human-like P4 dental root morphology

6 Ma: human-like foot morphology (loss of arborealism)

 

6-5 Ma: Pan / Homo diverge

5.9 – 5.3 Ma: Mediterranean Salinity Crisis: great unidirectional migrations of fauna away from the southern Med, towards Africa.

5.3 Ma: Zanclean Megaflood cuts off land bridge between Eurasia and Africa.

Pliocene: 5.3 – 2.6 Ma. Sea-levels rise by up to 30 m. Hyper aridity in the Arabian Peninsula prevents migration of fauna eastwards.

During much of this period, the Arabian Peninsula is effectively cut off from the rest of the world.

 

4-3 Ma (PTERV1 virus throughout Africa, affects all African apes, but not Homo or Orangutans)

 

[Panini / Australopithecines]

Climate: Loss of forests and wetlands, increase of savannah and mosaic environments

5-2 Ma: Gradual reversal from upright bipedalism towards arborealism, and eventually, knucklewalking (also in Gorilla – homoplasy).

 

[Early Homo]

2.6 – 2.0 Ma: Pleistocene cooling, sea-level decrease, vast intercontinental shelves appear, land bridges, intertidal zones, migration routes

2.0 Ma: Homo appears: taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism
More sophisticated stone tool use, shellfish consumption.

 

[Later Homo]

2.6 Ma – 2.0 Ka: Pleistocene cooling, sea-level decrease, fluctuating temperatures (between glacials).

Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?)

 

[Homo sapiens]

300 Ka – present: Holocene (relatively stable climate, less overall humidity)

More gracile forms (taller, thinner – like waders), rounder crania, shorter femoral necks (adaptation for running). Loss of platycephaly, heavy brow-ridges, elongated crania. Brain capacity reduction, flatter faces, smaller teeth, smaller noses, lighter bones, smaller thoracic capacity,

Suggests H. sapiens was more terrestrial than earlier Homo.

 

Present – future? Anthropocene: Global warming, global climate fluctuations, sea-level rise, mass extinction events…where next?

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 18, 2022 10:57 AM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Homo sapiens is, if anything, more aquatic than Homo erectus.

 

 

"As far back as 17 March 1960, Professor Sir Alister Hardy noted in The New Scientist that modern humans have many features that suggest an aquatic phase in our evolution at some time in the distant past.  

The assumption was that a group of primates became isolated on an island or some other inaccessible waterside environment and survived by becoming adapted to a semi-aquatic lifestyle in the course of that single evolutionary event. Subsequent discoveries have provided data that both support and contradict that hypothesis. 

The present investigation proposes an alternative model whereby, over millions of years, a series of emergencies, in the shape of climate fluctuations, from fertile to desert conditions and coinciding with glacial and interglacial epochs, repeatedly imposed very stringent survival pressures on every group of hominids. From the late Miocene onward, scores of such events dictated the selection criteria for gradual adaptation to an opportunistic aquatic diet in a punctuated series of evolutionary steps. 

These adaptations were cumulative, and the fossil record includes progressively more numerous examples of each new version of pre-human and human with the passage of time, progressively larger deposits of bivalve shells and other edible aquatic food species in shell middens, and more widely distributed locations for the stone tools needed to process them efficiently. 

This interpretation of the available evidence satisfies all the significant objections to Hardy’s theory and leads to the conclusion that, physiologically, we are more aquatic now than we have ever been, and the astonishing current world records for breath holding and free diving would seem to support that view."

 

The idea of a single, brief isolation event producing all (or any) of our aquatic adaptations was never really credible.

G.   

 


From: AAT@groups.io <AAT@groups.io> on behalf of algiskuliukas <algis@...>
Sent: Monday, April 18, 2022 10:07 AM
To: AAT@groups.io <AAT@groups.io>
Subject: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

For those of us who are open minded enough to answer Hardy's question "Was Man More Aquatic in the Past?" with a cautious affirmative, a second question follows "If, so when was that and how much?"

Having thought about this for twenty-five years and studied human evolution (MSc from UCL with distinction and PhD in human bipedal origins from UWA) I have come to the conclusion that the answer to the second question should be "very early modern Homo sapiens ca 200,000 years ago or so"... and... "not much".

Some proponents (e.g. Marc Verhaegen and Stephen Munro) would argue that a better answer would be "Homo erectus (sensu stricto) - i.e. the Asian, rather than African forms" and "that they were predominantly bottom divers."

That's quite a difference.

So, I'd like to discuss this openly to see if I have missed something. 

Let me start the ball rolling...

Marc always cites pacheostosis (heavy bones) of H. erectus as leaving "no other possibility" than bottom diving for this hominin but were their bones really that heavy? If you look at the Nariokotome boy femur, for example, it is remarkably gracile. Where are the papers in the literature that backs up this claim?

Marc also cites their pelvic shape as being platypelloid, with long femoral necks as further evidence but, again, that's not what I see in the literature. Nariokotome boy's pelvis is remarkably narrow actually, android rather than platypelloid. In any case what his platypelloidy got to do with bottom diving? Dugongs/manatees do not share this convergence. Their pelves, appear to be on their way to becoming vestigial like cetacea.

Whether they had heavy bones or not, there is undeniable evidence of significant weight bearing in the bones of Homo erectus. The tibial plate, the oval shaped distal femoral condyles, the robust femoral head, the large acetabulae with superiorly orientated lunate surface. The robust sacral body and large lumbar vertebrae all speak of an upright, walking, terrestrial striding biped - just like us. They seem to have been predominantly striding bipeds, not divers.

Please don't misunderstand me. I am not suggesting that Homo erectus did not swim or dive - just that they didn't do so very much, and specifically, not as much as we modern human did, or still do.

When Homo erectus reached the islands of Java and Flores some 1.8 million years ago, they could have done so without getting their feet wet as the current archipelago of Indonesia has been connected via land bridges from time to time. Of course, I have no doubt they often went swimming and diving in coastal shallows but, if they were as adept as Marc suggests (a predominantly bottom diver, remember) then it is remarkable that the narrow strait of water between Bali and Lombok across the Wallace line, just 20km wide, was never crossed by these diving hominins in 1.8 million years. If they did cross, they would have certainly populated the whole of the Australasian continent as that too was all joined by land at various times since. And yet we so no evidence of any human like species in Australia until 60,000 ago or so.

I must remind that modern humans regularly swim across such stretches of open water. The Perth - Rottnest swim is run every year and has thousands of participants. (https://en.wikipedia.org/wiki/Rottnest_Channel_Swim#:~:text=The%20distance%20is%2019.7%20km,teams%20of%20two%20or%20four.) It is about the same distance as Bali - Lombok via Penida. And of course far greater distances have been crossed than that, such as the Channel between England and France.

Of course, absence of evidence is not evidence of absence but, it seems to me that if we are to remain true to scientific principles we must base our ideas on evidence and here, the evidence is that Homo sapiens is, if anything, more aquatic than Homo erectus.

Algis Kuliukas
Perth
April 2022



[i] Carlson, K., et al.: The pectoral girdle of StW 573 ("Little Foot") and its implications for shoulder evolution in the Hominina. cs 2021 JHE in press. https://doi.org/10.1016/j.jhevol.2021.102983

[ii] Christine M. Harper, Christopher B. Ruff, Adam D. Sylvester, Calcaneal shape variation in humans, nonhuman primates, and early hominins, Journal of Human Evolution, Volume 159, 2021, 103050,

ISSN 0047-2484, https://doi.org/10.1016/j.jhevol.2021.103050. (https://www.sciencedirect.com/science/article/pii/S0047248421001020)

[iii] DeSilva, J, McNutt, E, Benoit, J, Zipfel, B. One small step: A review of Plio-Pleistocene hominin foot evolution. Am J Phys Anthropol. 2019; 168:S67: 63– 140. https://doi.org/10.1002/ajpa.23750

[iv] Rightmire GP. Homo erectus and Middle Pleistocene hominins: brain size, skull form, and species recognition. J Hum Evol. 2013 Sep;65(3):223-52. doi: 10.1016/j.jhevol.2013.04.008. Epub 2013 Jul 10. PMID: 23850294.

[v] Antón, S. C.; Taboada, H. G.; et al. (2016). "Morphological variation in Homo erectus and the origins of developmental plasticity". Philosophical Transactions of the Royal Society B. 371 (1698): 20150236. doi:10.1098/rstb.2015.0236. PMC 4920293. PMID 27298467.

[vi] Alexandra Houssaye, P. Martin Sander, Nicole Klein, Adaptive Patterns in Aquatic Amniote Bone Microanatomy—More Complex than Previously Thought, Integrative and Comparative Biology, Volume 56, Issue 6, December 2016, Pages 1349–1369, https://doi.org/10.1093/icb/icw120


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

Marc Verhaegen
 

Anthropocentric nonsense, they didn't even consider wading or swimming or diving.

_____


------ Origineel bericht ------
Van: needininfo@...
Aan: AAT@groups.io
Verzonden: woensdag 20 april 2022 15:23
Onderwerp: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

Bernie, See link and pdf to an excellent paper from 2018, it evaluated the hip and leg function of homo, great apes, Hylobates and a few fossils. Basically agrees with your thinking, our hips are crazy different. A radical bipedal solution appears out of nowhere.
Hip extensor mechanics and the evolution of walking and climbing capabilities in humans, apes, and fossil hominins

“Human bipedalism relies on a suite of hind limb adaptations, including a laterally oriented iliac blade and hip abductor complex, adducted hallux, and stiff midfoot (13), but few of these features have been linked empirically and in vivo to locomotor economy (i.e., the distance traveled per unit energy consumed). One derived feature tentatively tied to humans’ remarkable walking economy is a shorter and more dorsally projecting ischium, which permits hip extensor muscle torque production at full extension of the hip (180° hip angle between the trunk and leg) (4, 9, 14–16) (Fig. 1). The resulting straight-legged gait…”

https://www.pnas.org/doi/10.1073/pnas.1715120115


-Jack

On Apr 20, 2022, at 4:00 AM, Bernard Harper wrote:
Hi Everyone, I was looking for a mention of the earliest appearance together of three features that seem to be consistently "human": Tiny canines, flattened face and a human-like pelvis. Yet nobody has spoken of them either individually or collectively. Once our gait and our gape massively diverge from the ape, we are not an ape. So a date and explanation for their earliest divergence seems vital for this discussion to have clarity IMO.
Bernie Harper
www.bernieharper.co.uk



-- Welcome to the Aquatic Ape Theory Discussion Group


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

fceska_gr
 

Hi G.

 

Actually, I’m tempted to think that the most aquatic stage was pre-erectus as H. erectus had acquired most of their aquatic features by the time they appeared on the scene, c. 2 Ma, so clearly they were considerably aquatic before then. (IMO, this would be during our Red Sea, Arabian Peninsula, isolation/speciation phase, c.5 – 2.5 Ma during the Pliocene – just like Elaine always said – and the environmental and climatic conditions would support that they would have spent most of their time in the sea, but we have no fossil evidence so it’s just a hypothesis!)

 

There were many different versions of H. erectus and they existed for a long time. E.g., Turkana boy (H. ergaster/Africa) was more gracile and was found by a lake, whereas H. erectus (sensu stricto) / Javicus occupied coastal basins and river plains in Indonesia and was more robust, so probably dived in the sea more. But Meganthropus had even thicker bones than H. erectus, and was older (I’m still researching this – they’re a bit of an enigma). I’m not sure if Neanderthals were more or less aquatic than H.e, probably to a similar extent, but H.n dived in colder waters and probably had greater calorie requirements, so there was quite a lot different about their lifestyles.

 

F.

 

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Wednesday, April 20, 2022 7:34 PM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Great stuff, Francesca. Good points, well put. Will reply in full shortly. Meanwhile, for clarity, do you disagree with the proposition that "Homo erectus (sensu stricto) [was] the most aquatically adapted hominin", and are you saying that Neanderthal was ?

 

Thanks.

 

G.

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Wednesday, April 20, 2022 6:26 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

G: How do you determine tree climbing skills? In any case Australopiths were less aquatic than us and apparently are not considered ancestral to us anyway. This is all also predicated on the view that bipedalism is an aquatic adaptation. I don't think that was why it evolved originally.

 

F: “Many of the same features seen in australopithecines in Africa that are often cited as an indication of a species belonging to the human lineage, such as an anteriorly situated foramen magnum, short but broad ilia, relatively small canines, etc., are also found in many of the fossil apes from Europe (Wood & Harrison, 2011). Furthermore, if a taxon displays features both for bipedalism and arboreal climbing, it is traditionally understood to imply that the species is somehow transitional between a more arboreal earlier form and a later more terrestrial form, when it could just as easily have been going the other way. Evidence shows that some late australopithecines, such as Australopithecus sediba from 1.98 Ma, were more arboreal than earlier australopithecines, such as Australopithecus afarensis (Rein, et al., 2017*). The same could be said regarding brain sizes as we quite often see that the later australopithecines had smaller cranial capacities than earlier fossils. For example, from East Africa, the younger Paranthropus aethiopicus (2.7-2.3 Ma) had a cranium (c. 410 cc) falling within the range of the much older A. afarensis (c. 375-550 cc) at 3.9-2.9 Ma; while in South Africa, at 1. 98 Ma, A. sediba’s cranium was 420-450 cc and therefore smaller than A. prometheus’s cranium (500-520 cc) was already at 3.67 Ma. Although we are not claiming a direct line through any of these species, there is no clear trend showing that australopithecines were becoming more Homo-like over time.”

“Researchers compared A. prometheus’s shoulder to apes, hominins and humans and found that Little Foot was adapted to living partially in the trees and partially on the ground. As well as relatively long legs and limited bipedal foot morphology, it had a long, curved clavicle and dorsally positioned scapula with a high ridge to attach heavy muscles, ideal for supporting its weight below branch, more similar to that seen in arboreal apes, such as chimpanzees. They concluded that “the arm of our ancestors at 3.67 Ma was still (my emphasis) being used to bear substantial weight during arboreal movements in trees, for climbing or hanging beneath branches.” [i] The assumption here is that this is a retained feature from a more primitive ancestor, rather than the expression of an earlier adaptation as a result of returning to the trees.”

“In a recent paper, scientists revealed the results of a study in which they compared the heel bones (calcanei) of humans, extant apes and various hominin fossils. They found that earlier Australopithecus species, such as Lucy’s, had a heelbone more similar to humans than apes, better to support their weight on two legs, while later apiths had more ape-like heelbones, suggesting a reversal over time from bipedalism to arborealism.[ii] Other researchers studying hominin foot evolution have suggested that the similarities between A.afarensis’ feet and human feet might imply that they both “descend from a common ancestor with a similarly derived foot” and that “the large calcaneal tuber (heel bone) is obtained in developmentally different ways in A. afarensis and in modern humans.”[iii] In other words, homoplasy.”

 

*Adaptation to suspensory locomotion in Australopithecus sediba

https://www.sciencedirect.com/science/article/abs/pii/S0047248416302743

 

(I’m not claiming bipedalism is strictly aquatic, although I do think it emerged out of orthograde apes wading in wetlands in the first instance. And I don’t believe australopithecines are ancestral to us, but ancestral to the African apes, which is the point I’m making here).

 

There is evidence that Pan’s feet were once like ours

 

G: I have been looking long and hard and found nothing. This is quite important. I won't take it on trust. All the evidence (in utero, for instance) that I can find says the opposite.

 

F: Marc has always referenced C. S. Coon for this, but I haven’t been able to find the direct source. However, in another paper I found this (with no reference).

 

“The marked abductability of the chimpanzee hallux is probably a derived condition within the human/African ape clade. Indeed, embryos of chimpanzees have an adducted hallux suggesting that relative adduction could be the LCA primitive condition…”
Meldrum, Jeff & Sarmiento, Esteban. (2018). Comments on possible Miocene hominin footprints. Proceedings of the Geologists' Association. 129. 10.1016/j.pgeola.2018.05.006.

 

Also, Schultz, 1925 noted – although he doesn’t say at what stage this happens in chimpanzees…


“In all primates the great toe is found to branch from the sole, just at the base of the second toe, in very early growth stages. This embryonic position is retained throughout life in man, whereas in all other primates the place of attachment of the great toe shifts proximally, similar to the ontogenetic shifting in the attachment of the thumb to the palm from the base of the index finger to a place nearer the wrist. In the gorilla this shifting of the hallux is least pronounced of any of the apes, whereas it is most extreme in the orang, a greater difference existing in this respect between the latter and gorilla than between gorilla and man (fig. 16). Other propor tions on the foot lead to similar conclusions…”

https://www.jstor.org/stable/pdf/24527371.pdf

 

G: If there have been no reversals, then in what possible sense can we be less aquatic than we used to be?

 

F: There are many ways. Read the paragraph I wrote further down about ‘reduction’ of features (smaller lungs, etc.), and this is only from fossil evidence, which is very limited, and based on comparative anatomy with other species, so we can’t really know what other features we may have fully lost. Maybe we did have webbing between our fingers & toes… (!!)

 

I’m talking about Pan (chimps) not Homo.

 

G: The premise I thought we were discussing was the one about whether early Homo was more or less aquatic than us. Whether chimps reverted or not really doesn't have any bearing.

 

F: Yes, we were, but earlier we were also talking about climate and how it instigated evolutionary changes. I included a small two-line reference to Panins to suggest why the australopithecines may have become more arboreal as the African wetlands dried up.

 

Thick brow ridges are great if you dive, browse and forage underwater... to push water away from the eyes

G: This is simply not true. I've mentioned katabatic flow to you before. When any fluid flows over a ridge it drives forcibly down the other side. Into your eyes in other words if it is a brow ridge.

 

F: I’m not convinced by this but clearly more research is needed. I suppose it is testable. The example you give is based on air, not water, and presumes a straight directional flow over the ridge. I believe the brows on a hominin, face down in water, would divert the flow of water away to the sides of the face. Maybe it’s not so much to do with swimming but even surfacing regularly to breathe. With a flat face and no brows the water would just pour straight down into your gasping mouth. In general, our brows are thought to be useful in diverting sweat from flowing into our eyes, so the same principle is true, but just with more water, more regularly.

 

And how do you get “more aquatic” Asian people? Some are, of course, if you’re thinking of Moken, etc. or Japanese pearl divers, but can we say Asians are more aquatic. We are all still H.sapiens.

 

Neanderthals were more aquatic than Homo sapiens. 

 

G: A bigger brain, I happily concede. However all the known big headed humanoids became extinct -- proto-Innuit, Boskop man, "coneheads", Neanderthals.... The fact that fewer and fewer females appeared over time suggests that heads became too big to pass through the birth canal, killing the mothers in childbirth. We are about on the sustainable limit, partly thanks to Caesarian sections. A reality that anthropologists manage to ignore, preferring to focus on how jolly intelligent they think they are.

 

F: Is that a fact? Do you have a reference? We don’t know why Neanderthals went extinct. Many reasons are proposed.

 

G: Homo erectus had a tiny brain anyway. Are we to conclude then that he was less aquatic than us? Makes sense. We just can't have it both ways.

 

F: Homo erectus’ brain capacity, with an average of 950cc, [iv] ranged from 550cc in some early samples, to 1251 cc,[v] which is close to that found in modern humans. (I personally believe that brain size increase is a result of marine-chain based nutrients + cold water, which explains the size increase as the climate got cooler. Neanderthals with the largest brains, swam in the cold waters of the Atlantic. Only a more aquatic species would do that regularly, don’t you think?).

 

G: Big, heavy bones are really a huge handicap in the water if you think about it. Bad for swimming and floating. Good, on the way down, for diving. Coming up...  good for drowning. Manageable in sea water. Big problem in fresh. Neanderthal was robust because, like Australopithecus robustus, he was designed to live mostly on land and struggled to make a living in the water, not yet having our perfect neutral buoyancy and other modern refinements. Frequently fractured his skull diving in, apparently.

 

F: “In the animal kingdom, good runners tend to be gracile, or lightly built, (e.g., cheetahs, antelopes, horses, greyhounds), and even floating semi-aquatic animals such as ducks have light bones. Conversely, dense, heavy bones tend to be brittle and not suitable for fast or sustained terrestrial locomotion. As noted by Alexandra Houssaye, et al, in their study of amniote bone microanatomy regarding thick cortical bones: “These rather well-known specializations are considered incompatible with a terrestrial locomotion and generally do not occur (or incipiently so) in terrestrial taxa… or even in most semi-aquatic taxa.” In contrast, bone mass increase is found “in almost all highly or exclusively aquatic amniotes foraging below the water surface.[vi]

 

Seems quite clear to me that both erectus and Neanderthals, with their heavier, more robust bones, were better suited to shallow diving and totally incompatible with running. And possibly why women have more fat then men (males may have been deeper divers) and why women gain fat & lose bone density after menopause when they have to be floating around at the surface with the grandkids.

 

G: As you know I consider the most aquatic hominin ever was Strandlooper (Boskop man) -- extinct for only a few hundred years or so. If you look at all the (aquatic) features that distinguish us from earlier ancestors, Strandlooper had them all, but very much more so. We know they were fully dependent on marine resources, because to find even a blade of grass they would have had to cross both the Kalahari and the Namib deserts, the latter having existed for over 50 million years, and you can see their shell middens from many miles away.. 

 

They were more gracile than us. "paper thin ribs" Their brains were a full 30% bigger than ours (forebrains + 50%). No brow ridge at all. Tiny teeth. Very prominent, sharp chin. Different in every way from the rugged Neanderthals. More aquatic....

 

F: I can’t comment on Strandloopers – I haven’t researched them yet. It sounds as though there are a mix of features. If they had gracile bones, they may have been surface swimmers rather than divers.

 

 just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. 

 

G: Precisely, then we obviously have more aquatic adaptations than any previous hominin who hadn't yet developed them. i.e we are the most aquatic (surviving) hominin.

 

F: Not losing a feature doesn’t mean it still serves its original function, especially if it is reduced. I repeat: we have smaller lungs, longer legs, lighter bones & shorter femora (better adapted to terrestrial locomotion than our ancestors), more globular crania, lower eyes, flatter faces (better when standing erect), smaller brains (less swimming in cold water, less seafood consumption, self-domestication-agriculture), we are probably less fat than Neanderthals (although they weren’t direct ancestors, we seem to have inherited our fat genes from them). Also, we cannot say that modern Homo sapiens – as a whole – is predominantly aquatic anymore. We retain some reduced aquatic features and tendencies. The whole point of the “Scars of Evolution” (E. Morgan) is that our scars are the remnants of a more aquatic past. Hardy and Morgan had it right. We were more aquatic in the past, but we can agree to disagree as everyone does here! 😊

 

QED.

 

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Tuesday, April 19, 2022 10:54 PM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

The climate I refer to from Miocene onwards is all supported by scientific research.

 

Yes. It's only the older stuff I decline to offer any opinions on.

 

 

There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel  

 

I have no problem with that.

 

 

 

 Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

 

Smaller, maybe. How do you determine tree climbing skills? In any case Australopiths were less aquatic than us and apparently are not considered ancestral to us anyway. This is all also predicated on the view that bipedalism is an aquatic adaptation. I don't think that was why it evolved originally.

 

There is evidence that Pan’s feet were once like ours

 

I have been looking long and hard and found nothing. This is quite important. I won't take it on trust. All the evidence (in utero, for instance) that I can find says the opposite.

 

 

 

I think you misunderstood me… there was only one reversal

 

Great. If there have been no reversals, then in what possible sense can we be less aquatic than we used to be?

 

 

I’m talking about Pan (chimps) not Homo.

 

The premise I thought we were discussing was the one about whether early Homo was more or less aquatic than us. Whether chimps reverted or not really doesn't have any bearing.

 

 

 

Thick brow ridges are great if you dive, browse and forage underwater... to push water away from the eyes

 

This is simply not true. I've mentioned katabatic flow to you before. When any fluid flows over a ridge it drives forcibly down the other side. Into your eyes in other words if it is a brow ridge. Here's a diagram of a "Chinook wind" to illustrate what happens.

 

 

"A 40- to 50-mph wind over the ridges and passes may reach speeds of 80 to 100 mph by the time the air reaches the foothills (on the other side)".

 

It therefore follows that losing the brow ridge makes for better underwater vision. The more aquatic Asian people have less of a brow ridge than westerners and modern Man has a more "streamlined" face than any previous ancestor. i.e. more aquatic.

 

 

 

Neanderthals were more aquatic than Homo sapiens. 

 

A bigger brain, I happily concede. However all the known big headed humanoids became extinct -- proto-Innuit, Boskop man, "coneheads", Neanderthals.... The fact that fewer and fewer females appeared over time suggests that heads became too big to pass through the birth canal, killing the mothers in childbirth. We are about on the sustainable limit, partly thanks to Caesarian sections. A reality that anthropologists manage to ignore, preferring to focus on how jolly intelligent they think they are.

 

Homo erectus had a tiny brain anyway. Are we to conclude then that he was less aquatic than us? Makes sense. We just can't have it both ways.

 

Big, heavy bones are really a huge handicap in the water if you think about it. Bad for swimming and floating. Good, on the way down, for diving. Coming up...  good for drowning. Manageable in sea water. Big problem in fresh. Neanderthal was robust because, like Australopithecus robustus, he was designed to live mostly on land and struggled to make a living in the water, not yet having our perfect neutral buoyancy and other modern refinements. Frequently fractured his skull diving in, apparently.

 

 

As you know I consider the most aquatic hominin ever was Strandlooper (Boskop man) -- extinct for only a few hundred years or so. If you look at all the (aquatic) features that distinguish us from earlier ancestors, Strandlooper had them all, but very much more so. We know they were fully dependent on marine resources, because to find even a blade of grass they would have had to cross both the Kalahari and the Namib deserts, the latter having existed for over 50 million years, and you can see their shell middens from many miles away.. 

 

They were more gracile than us. "paper thin ribs" Their brains were a full 30% bigger than ours (forebrains + 50%). No brow ridge at all. Tiny teeth. Very prominent, sharp chin. Different in every way from the rugged Neanderthals. More aquatic....

 

 

 just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. 

 

 

Precisely, then we obviously have more aquatic adaptations than any previous hominin who hadn't yet developed them. i.e we are the most aquatic (surviving) hominin.

 

QED.

 

G.

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 7:02 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Thanks, Gareth

Thanks, Francesca.

 

Would it be possible to reveal the source of this text

 

That would be me.  Email, subject "Second draft" about where when and how we became aquatic.

Ok, thanks. I’ll have another look for it.

 

 many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

Agreed. But they didn't spring up, fully formed overnight. They gradually improved, gradually increased in number and range of functions.

Agreed, that’s what I’ve been writing about.

 

I'm not making any guesses about what happened before the Miocene --  what the climate was like in some particular region, tectonic events, sea levels, vegetation, predators or the particular 'cause' of any specific change in physiology. For one thing I'm sure that none of these conditions remained unchanged for millions of years at any point, so too much of it is guesswork based on insufficient evidence. Almost anything could have happened somewhere at some point.

The climate I refer to from Miocene onwards is all supported by scientific research.

 

reversal from upright bipedalism towards arborealism

 

Not aware of any evidence for this "reversal". Not to say it couldn't or didn't happen, but if I ever knew of any evidence, I've forgotten.

There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel, from an already upright common ancestor, after splitting from a common ancestor. First they walked on 4 legs, then they walked on 2, then they walked on their knuckles.

Many of the australopithecines seem to become more arboreal over time, not less. Eg. Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

 

My only comments would be that, once we learned to throw, we were never able to brachiate again because of the change in orientation of our pectoral muscle.. Once we became bipedal, the loss of the divergent hallux meant we could never grasp a branch with our feet again. Not sure what kind of arborealism this would leave us. 

Humans didn’t become arboreal again, only Pan did. The point I’m trying to make is that the LCA was probably already a biped. After we split, the Pan line remained bipedal (wading, wetland foraging) for a while, but later, they returned to the forests, started climbing trees and walking on their knuckles when on the ground. There is evidence that Pan’s feet were once like ours (adducted halluces) but later their big toe moved round to the side and they could grasp branches again. (Pan foetus in utero).

 

 I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

We need to look at the other features that you consider reversals to see if any of them are aquatic features that we have lost since early Homo....

I think you misunderstood me… there was only one reversal I mentioned and that was in chimps…

 

You mention...

 

6 Ma: human-like foot morphology (loss of arborealism). -- Arborealism is definitely not aquatic.

That’s my point. We lost arboreal features because we became more aquatic. Or, because we became more aquatic, we lost arboreal climbing abilities.

 

5-2 Ma: Gradual reversal from upright bipedalism. -- Don't think I believe this (Open to persuasion. See above.) but anyway bipedalism is either not essentially aquatic, in which case it's irrelevant or it is, in which case we have become more aquatic (more upright), not less, since early Homo.

Yes, again, I think you’ve misunderstood me. Here I’m talking about Pan (chimps) not Homo. Reverse adaptations in evolution are more common even than first time adaptations. It happens all the time. It’s a result of gene expression. Once the gene exists, it can be switched on or off, according to need. That’s why snakes evolved legs, then lost them again. So did whales, etc. Chimp and human ancestors lost their fur, then chimps grew theirs again, but we didn’t. Early elephants lost their fur but woolly mammoths grew it back as they moved north. Some people are sometimes born with a tail, or webbing between their toes, because those genes still exist, even if silenced at the moment.

 

I think Homo is closer to the LCA in morphology than chimps. We haven’t changed as much as they have over the past 5-6 million years, and this is seen in their Y-chromosome. And most of those changes in chimps probably happened in the last million years or so, after they diverged from bonobos. Bonobos are more like us than chimps are (see picture attached).

 

2.0 Ma: Homo appears:  taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism, more sophisticated stone tool use, shellfish consumption. -- Other than the thick brow ridges (survival benefit not obvious to me) these all seem to be increases in aquatic adaptation.

Thick brow ridges are great if you dive, browse and forage underwater. Like a hooded nose, they act together to push water away from the eyes and nostrils as you move forward.
And yes, this is meant to demonstrate increases in aquatic adaptation. My point is, early Homo at 2 Ma was far more aquatic morphologically than H. sapiens is now.

 

300 ka to present: Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?) -- Again these seem to be evidence of a more aquatic lifestyle, not less.

Yes, Neanderthals were more aquatic than Homo sapiens. Again, that’s my point.

 

Which aquatic features do you think we have lost, then? What makes you think we are less well adapted to warm, cold, shallow, deep, clean, muddy, fresh or salt water than any of the less derived hominins? Your entire timeline seems perfectly to support my observation that aquatic adaptations have been a gradual, punctuated, cumulative process that has continued till today.

We haven’t fully lost any of those earlier adaptations (that we know of) but each is less pronounced. We have smaller thoraxes and reduced lung capacity compared to early Homo, as we don’t dive as much. We have lighter bones because we walk/run more, swim and dive less. We can’t see well underwater unless this skill is practised from childhood. We have less pronounced brow ridges for the same reason. We have rounder crania as we spend more time standing upright, whereas the more elongated crania of early Homo is better supported in a swimming, floating or diving position. We can swim and dive pretty well, for an ape, but not as well as erectus probably did. They may have been able to swim vast distances and dive to much deeper levels. They could probably hold their breath much longer than we can, or close to what professional / record holding divers can do now.

 

As your mum once wrote, just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. We would only lose it if keeping it was detrimental to our survival. We haven’t regrown our fur because we discovered clothes and central heating as an alternative means of keeping warm (and still get to go to the beach!) If we hadn’t, only the most hairy of us would survive in a colder climate to pass on our genes, so over time, our children would get hairier and hairier. We didn’t revert to quadrupedalism because by the time we became fully terrestrial again, our legs were much longer in relation to our arms and so the proportions were all wrong. Plus, we didn’t need to. By then we were quite comfortable moving around on 2 legs and using our forelimbs for other purposes. It’s served us quite well.

 

F.

G.

 

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 12:19 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Hi Gareth,

 

Would it be possible to reveal the source of this text, please? I’d like to read it.

 

I agree that climate has influenced anthropoid evolution at many stages and in different ways, although I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

If we look at the evidence, many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

[1st aquatic stage: Hominoidea]

30-25 Ma Climate: very hot, humid, subtropical forests; tectonic upheaval and rifting causing vast areas of East Africa to become flooded, creating forested islands in vast East African lakes.

25-20 Ma: orthograde body plan and modifications towards bipedal posture, suspensory adaptations of the wrist, hand, shoulders and arms, larger, wider thorax, loss of tail, etc.
20 – 14 Ma: gradual increase in size from small-bodied primates to large chimp sized apes

Some time between 25 Ma and 16 Ma: partial loss of pelage (great apes relative to macaques)

Overall increase in eccrine gland distribution (between OWMs and apes)

Probable reduction in olfactory ability

PNS

c. 18- 16 Ma Hylobatidae diverge

 

16-14 Ma: Climate: temperature decrease, reduced humidity & loss of biodiversity in Africa; increasing biodiversity, humid sub-tropical forests & vast bodies of water in Eurasia, land bridges between the two continents. Disappearance of most apes from Africa. Appearance of many ape species in Eurasia.

15 Ma: loss of uricase mutation and the ability to store sugars as fat

 

[Hominidae]

15-13 Ma: the ability to fashion stone tools

c. 15-14 Ma: Pongo diverges

14 Ma: plantigrade locomotion (quadrupedal)

12-11 Ma: loss of prognathism, robust jaws, postural bipedalism (wading)

11-9 Ma: Vallesian crisis causes the extinction of many apes (loss of forests, loss of edible fruits, spreading grasslands, seasonal food availability).

10-7 Ma: bipedal hominids roam the river valleys & great lakes of southern Europe & the Tethys-Med coasts.
Smaller, more thickly enamelled dentition – change of diet.

 

[Homininae]

10-6 Ma: terrestrial bipedalism develops

c. 10-8 Ma: gorilla divergence

7 Ma: human-like P4 dental root morphology

6 Ma: human-like foot morphology (loss of arborealism)

 

6-5 Ma: Pan / Homo diverge

5.9 – 5.3 Ma: Mediterranean Salinity Crisis: great unidirectional migrations of fauna away from the southern Med, towards Africa.

5.3 Ma: Zanclean Megaflood cuts off land bridge between Eurasia and Africa.

Pliocene: 5.3 – 2.6 Ma. Sea-levels rise by up to 30 m. Hyper aridity in the Arabian Peninsula prevents migration of fauna eastwards.

During much of this period, the Arabian Peninsula is effectively cut off from the rest of the world.

 

4-3 Ma (PTERV1 virus throughout Africa, affects all African apes, but not Homo or Orangutans)

 

[Panini / Australopithecines]

Climate: Loss of forests and wetlands, increase of savannah and mosaic environments

5-2 Ma: Gradual reversal from upright bipedalism towards arborealism, and eventually, knucklewalking (also in Gorilla – homoplasy).

 

[Early Homo]

2.6 – 2.0 Ma: Pleistocene cooling, sea-level decrease, vast intercontinental shelves appear, land bridges, intertidal zones, migration routes

2.0 Ma: Homo appears: taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism
More sophisticated stone tool use, shellfish consumption.

 

[Later Homo]

2.6 Ma – 2.0 Ka: Pleistocene cooling, sea-level decrease, fluctuating temperatures (between glacials).

Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?)

 

[Homo sapiens]

300 Ka – present: Holocene (relatively stable climate, less overall humidity)

More gracile forms (taller, thinner – like waders), rounder crania, shorter femoral necks (adaptation for running). Loss of platycephaly, heavy brow-ridges, elongated crania. Brain capacity reduction, flatter faces, smaller teeth, smaller noses, lighter bones, smaller thoracic capacity,

Suggests H. sapiens was more terrestrial than earlier Homo.

 

Present – future? Anthropocene: Global warming, global climate fluctuations, sea-level rise, mass extinction events…where next?

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 18, 2022 10:57 AM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Homo sapiens is, if anything, more aquatic than Homo erectus.

 

 

"As far back as 17 March 1960, Professor Sir Alister Hardy noted in The New Scientist that modern humans have many features that suggest an aquatic phase in our evolution at some time in the distant past.  

The assumption was that a group of primates became isolated on an island or some other inaccessible waterside environment and survived by becoming adapted to a semi-aquatic lifestyle in the course of that single evolutionary event. Subsequent discoveries have provided data that both support and contradict that hypothesis. 

The present investigation proposes an alternative model whereby, over millions of years, a series of emergencies, in the shape of climate fluctuations, from fertile to desert conditions and coinciding with glacial and interglacial epochs, repeatedly imposed very stringent survival pressures on every group of hominids. From the late Miocene onward, scores of such events dictated the selection criteria for gradual adaptation to an opportunistic aquatic diet in a punctuated series of evolutionary steps. 

These adaptations were cumulative, and the fossil record includes progressively more numerous examples of each new version of pre-human and human with the passage of time, progressively larger deposits of bivalve shells and other edible aquatic food species in shell middens, and more widely distributed locations for the stone tools needed to process them efficiently. 

This interpretation of the available evidence satisfies all the significant objections to Hardy’s theory and leads to the conclusion that, physiologically, we are more aquatic now than we have ever been, and the astonishing current world records for breath holding and free diving would seem to support that view."

 

The idea of a single, brief isolation event producing all (or any) of our aquatic adaptations was never really credible.

G.   

 


From: AAT@groups.io <AAT@groups.io> on behalf of algiskuliukas <algis@...>
Sent: Monday, April 18, 2022 10:07 AM
To: AAT@groups.io <AAT@groups.io>
Subject: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

For those of us who are open minded enough to answer Hardy's question "Was Man More Aquatic in the Past?" with a cautious affirmative, a second question follows "If, so when was that and how much?"

Having thought about this for twenty-five years and studied human evolution (MSc from UCL with distinction and PhD in human bipedal origins from UWA) I have come to the conclusion that the answer to the second question should be "very early modern Homo sapiens ca 200,000 years ago or so"... and... "not much".

Some proponents (e.g. Marc Verhaegen and Stephen Munro) would argue that a better answer would be "Homo erectus (sensu stricto) - i.e. the Asian, rather than African forms" and "that they were predominantly bottom divers."

That's quite a difference.

So, I'd like to discuss this openly to see if I have missed something. 

Let me start the ball rolling...

Marc always cites pacheostosis (heavy bones) of H. erectus as leaving "no other possibility" than bottom diving for this hominin but were their bones really that heavy? If you look at the Nariokotome boy femur, for example, it is remarkably gracile. Where are the papers in the literature that backs up this claim?

Marc also cites their pelvic shape as being platypelloid, with long femoral necks as further evidence but, again, that's not what I see in the literature. Nariokotome boy's pelvis is remarkably narrow actually, android rather than platypelloid. In any case what his platypelloidy got to do with bottom diving? Dugongs/manatees do not share this convergence. Their pelves, appear to be on their way to becoming vestigial like cetacea.

Whether they had heavy bones or not, there is undeniable evidence of significant weight bearing in the bones of Homo erectus. The tibial plate, the oval shaped distal femoral condyles, the robust femoral head, the large acetabulae with superiorly orientated lunate surface. The robust sacral body and large lumbar vertebrae all speak of an upright, walking, terrestrial striding biped - just like us. They seem to have been predominantly striding bipeds, not divers.

Please don't misunderstand me. I am not suggesting that Homo erectus did not swim or dive - just that they didn't do so very much, and specifically, not as much as we modern human did, or still do.

When Homo erectus reached the islands of Java and Flores some 1.8 million years ago, they could have done so without getting their feet wet as the current archipelago of Indonesia has been connected via land bridges from time to time. Of course, I have no doubt they often went swimming and diving in coastal shallows but, if they were as adept as Marc suggests (a predominantly bottom diver, remember) then it is remarkable that the narrow strait of water between Bali and Lombok across the Wallace line, just 20km wide, was never crossed by these diving hominins in 1.8 million years. If they did cross, they would have certainly populated the whole of the Australasian continent as that too was all joined by land at various times since. And yet we so no evidence of any human like species in Australia until 60,000 ago or so.

I must remind that modern humans regularly swim across such stretches of open water. The Perth - Rottnest swim is run every year and has thousands of participants. (https://en.wikipedia.org/wiki/Rottnest_Channel_Swim#:~:text=The%20distance%20is%2019.7%20km,teams%20of%20two%20or%20four.) It is about the same distance as Bali - Lombok via Penida. And of course far greater distances have been crossed than that, such as the Channel between England and France.

Of course, absence of evidence is not evidence of absence but, it seems to me that if we are to remain true to scientific principles we must base our ideas on evidence and here, the evidence is that Homo sapiens is, if anything, more aquatic than Homo erectus.

Algis Kuliukas
Perth
April 2022



[i] Carlson, K., et al.: The pectoral girdle of StW 573 ("Little Foot") and its implications for shoulder evolution in the Hominina. cs 2021 JHE in press. https://doi.org/10.1016/j.jhevol.2021.102983

[ii] Christine M. Harper, Christopher B. Ruff, Adam D. Sylvester, Calcaneal shape variation in humans, nonhuman primates, and early hominins, Journal of Human Evolution, Volume 159, 2021, 103050,

ISSN 0047-2484, https://doi.org/10.1016/j.jhevol.2021.103050. (https://www.sciencedirect.com/science/article/pii/S0047248421001020)

[iii] DeSilva, J, McNutt, E, Benoit, J, Zipfel, B. One small step: A review of Plio-Pleistocene hominin foot evolution. Am J Phys Anthropol. 2019; 168:S67: 63– 140. https://doi.org/10.1002/ajpa.23750

[iv] Rightmire GP. Homo erectus and Middle Pleistocene hominins: brain size, skull form, and species recognition. J Hum Evol. 2013 Sep;65(3):223-52. doi: 10.1016/j.jhevol.2013.04.008. Epub 2013 Jul 10. PMID: 23850294.

[v] Antón, S. C.; Taboada, H. G.; et al. (2016). "Morphological variation in Homo erectus and the origins of developmental plasticity". Philosophical Transactions of the Royal Society B. 371 (1698): 20150236. doi:10.1098/rstb.2015.0236. PMC 4920293. PMID 27298467.

[vi] Alexandra Houssaye, P. Martin Sander, Nicole Klein, Adaptive Patterns in Aquatic Amniote Bone Microanatomy—More Complex than Previously Thought, Integrative and Comparative Biology, Volume 56, Issue 6, December 2016, Pages 1349–1369, https://doi.org/10.1093/icb/icw120


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

Gareth Morgan
 

Great stuff, Francesca. Good points, well put. Will reply in full shortly. Meanwhile, for clarity, do you disagree with the proposition that "Homo erectus (sensu stricto) [was] the most aquatically adapted hominin", and are you saying that Neanderthal was ?

Thanks.

G.


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Wednesday, April 20, 2022 6:26 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?
 

G: How do you determine tree climbing skills? In any case Australopiths were less aquatic than us and apparently are not considered ancestral to us anyway. This is all also predicated on the view that bipedalism is an aquatic adaptation. I don't think that was why it evolved originally.

 

F: “Many of the same features seen in australopithecines in Africa that are often cited as an indication of a species belonging to the human lineage, such as an anteriorly situated foramen magnum, short but broad ilia, relatively small canines, etc., are also found in many of the fossil apes from Europe (Wood & Harrison, 2011). Furthermore, if a taxon displays features both for bipedalism and arboreal climbing, it is traditionally understood to imply that the species is somehow transitional between a more arboreal earlier form and a later more terrestrial form, when it could just as easily have been going the other way. Evidence shows that some late australopithecines, such as Australopithecus sediba from 1.98 Ma, were more arboreal than earlier australopithecines, such as Australopithecus afarensis (Rein, et al., 2017*). The same could be said regarding brain sizes as we quite often see that the later australopithecines had smaller cranial capacities than earlier fossils. For example, from East Africa, the younger Paranthropus aethiopicus (2.7-2.3 Ma) had a cranium (c. 410 cc) falling within the range of the much older A. afarensis (c. 375-550 cc) at 3.9-2.9 Ma; while in South Africa, at 1. 98 Ma, A. sediba’s cranium was 420-450 cc and therefore smaller than A. prometheus’s cranium (500-520 cc) was already at 3.67 Ma. Although we are not claiming a direct line through any of these species, there is no clear trend showing that australopithecines were becoming more Homo-like over time.”

“Researchers compared A. prometheus’s shoulder to apes, hominins and humans and found that Little Foot was adapted to living partially in the trees and partially on the ground. As well as relatively long legs and limited bipedal foot morphology, it had a long, curved clavicle and dorsally positioned scapula with a high ridge to attach heavy muscles, ideal for supporting its weight below branch, more similar to that seen in arboreal apes, such as chimpanzees. They concluded that “the arm of our ancestors at 3.67 Ma was still (my emphasis) being used to bear substantial weight during arboreal movements in trees, for climbing or hanging beneath branches.” [i] The assumption here is that this is a retained feature from a more primitive ancestor, rather than the expression of an earlier adaptation as a result of returning to the trees.”

“In a recent paper, scientists revealed the results of a study in which they compared the heel bones (calcanei) of humans, extant apes and various hominin fossils. They found that earlier Australopithecus species, such as Lucy’s, had a heelbone more similar to humans than apes, better to support their weight on two legs, while later apiths had more ape-like heelbones, suggesting a reversal over time from bipedalism to arborealism.[ii] Other researchers studying hominin foot evolution have suggested that the similarities between A.afarensis’ feet and human feet might imply that they both “descend from a common ancestor with a similarly derived foot” and that “the large calcaneal tuber (heel bone) is obtained in developmentally different ways in A. afarensis and in modern humans.”[iii] In other words, homoplasy.

 

*Adaptation to suspensory locomotion in Australopithecus sediba

https://www.sciencedirect.com/science/article/abs/pii/S0047248416302743

 

(I’m not claiming bipedalism is strictly aquatic, although I do think it emerged out of orthograde apes wading in wetlands in the first instance. And I don’t believe australopithecines are ancestral to us, but ancestral to the African apes, which is the point I’m making here).

 

There is evidence that Pan’s feet were once like ours

 

G: I have been looking long and hard and found nothing. This is quite important. I won't take it on trust. All the evidence (in utero, for instance) that I can find says the opposite.

 

F: Marc has always referenced C. S. Coon for this, but I haven’t been able to find the direct source. However, in another paper I found this (with no reference).

 

“The marked abductability of the chimpanzee hallux is probably a derived condition within the human/African ape clade. Indeed, embryos of chimpanzees have an adducted hallux suggesting that relative adduction could be the LCA primitive condition…”
Meldrum, Jeff & Sarmiento, Esteban. (2018). Comments on possible Miocene hominin footprints. Proceedings of the Geologists' Association. 129. 10.1016/j.pgeola.2018.05.006.

 

Also, Schultz, 1925 noted – although he doesn’t say at what stage this happens in chimpanzees…


“In all primates the great toe is found to branch from the sole, just at the base of the second toe, in very early growth stages. This embryonic position is retained throughout life in man, whereas in all other primates the place of attachment of the great toe shifts proximally, similar to the ontogenetic shifting in the attachment of the thumb to the palm from the base of the index finger to a place nearer the wrist. In the gorilla this shifting of the hallux is least pronounced of any of the apes, whereas it is most extreme in the orang, a greater difference existing in this respect between the latter and gorilla than between gorilla and man (fig. 16). Other propor tions on the foot lead to similar conclusions…”

https://www.jstor.org/stable/pdf/24527371.pdf

 

G: If there have been no reversals, then in what possible sense can we be less aquatic than we used to be?

 

F: There are many ways. Read the paragraph I wrote further down about ‘reduction’ of features (smaller lungs, etc.), and this is only from fossil evidence, which is very limited, and based on comparative anatomy with other species, so we can’t really know what other features we may have fully lost. Maybe we did have webbing between our fingers & toes… (!!)

 

I’m talking about Pan (chimps) not Homo.

 

G: The premise I thought we were discussing was the one about whether early Homo was more or less aquatic than us. Whether chimps reverted or not really doesn't have any bearing.

 

F: Yes, we were, but earlier we were also talking about climate and how it instigated evolutionary changes. I included a small two-line reference to Panins to suggest why the australopithecines may have become more arboreal as the African wetlands dried up.

 

Thick brow ridges are great if you dive, browse and forage underwater... to push water away from the eyes

G: This is simply not true. I've mentioned katabatic flow to you before. When any fluid flows over a ridge it drives forcibly down the other side. Into your eyes in other words if it is a brow ridge.

 

F: I’m not convinced by this but clearly more research is needed. I suppose it is testable. The example you give is based on air, not water, and presumes a straight directional flow over the ridge. I believe the brows on a hominin, face down in water, would divert the flow of water away to the sides of the face. Maybe it’s not so much to do with swimming but even surfacing regularly to breathe. With a flat face and no brows the water would just pour straight down into your gasping mouth. In general, our brows are thought to be useful in diverting sweat from flowing into our eyes, so the same principle is true, but just with more water, more regularly.

 

And how do you get “more aquatic” Asian people? Some are, of course, if you’re thinking of Moken, etc. or Japanese pearl divers, but can we say Asians are more aquatic. We are all still H.sapiens.

 

Neanderthals were more aquatic than Homo sapiens. 

 

G: A bigger brain, I happily concede. However all the known big headed humanoids became extinct -- proto-Innuit, Boskop man, "coneheads", Neanderthals.... The fact that fewer and fewer females appeared over time suggests that heads became too big to pass through the birth canal, killing the mothers in childbirth. We are about on the sustainable limit, partly thanks to Caesarian sections. A reality that anthropologists manage to ignore, preferring to focus on how jolly intelligent they think they are.

 

F: Is that a fact? Do you have a reference? We don’t know why Neanderthals went extinct. Many reasons are proposed.

 

G: Homo erectus had a tiny brain anyway. Are we to conclude then that he was less aquatic than us? Makes sense. We just can't have it both ways.

 

F: Homo erectus’ brain capacity, with an average of 950cc, [iv] ranged from 550cc in some early samples, to 1251 cc,[v] which is close to that found in modern humans. (I personally believe that brain size increase is a result of marine-chain based nutrients + cold water, which explains the size increase as the climate got cooler. Neanderthals with the largest brains, swam in the cold waters of the Atlantic. Only a more aquatic species would do that regularly, don’t you think?).

 

G: Big, heavy bones are really a huge handicap in the water if you think about it. Bad for swimming and floating. Good, on the way down, for diving. Coming up...  good for drowning. Manageable in sea water. Big problem in fresh. Neanderthal was robust because, like Australopithecus robustus, he was designed to live mostly on land and struggled to make a living in the water, not yet having our perfect neutral buoyancy and other modern refinements. Frequently fractured his skull diving in, apparently.

 

F: “In the animal kingdom, good runners tend to be gracile, or lightly built, (e.g., cheetahs, antelopes, horses, greyhounds), and even floating semi-aquatic animals such as ducks have light bones. Conversely, dense, heavy bones tend to be brittle and not suitable for fast or sustained terrestrial locomotion. As noted by Alexandra Houssaye, et al, in their study of amniote bone microanatomy regarding thick cortical bones: “These rather well-known specializations are considered incompatible with a terrestrial locomotion and generally do not occur (or incipiently so) in terrestrial taxa… or even in most semi-aquatic taxa.” In contrast, bone mass increase is found “in almost all highly or exclusively aquatic amniotes foraging below the water surface.[vi]

 

Seems quite clear to me that both erectus and Neanderthals, with their heavier, more robust bones, were better suited to shallow diving and totally incompatible with running. And possibly why women have more fat then men (males may have been deeper divers) and why women gain fat & lose bone density after menopause when they have to be floating around at the surface with the grandkids.

 

G: As you know I consider the most aquatic hominin ever was Strandlooper (Boskop man) -- extinct for only a few hundred years or so. If you look at all the (aquatic) features that distinguish us from earlier ancestors, Strandlooper had them all, but very much more so. We know they were fully dependent on marine resources, because to find even a blade of grass they would have had to cross both the Kalahari and the Namib deserts, the latter having existed for over 50 million years, and you can see their shell middens from many miles away.. 

 

They were more gracile than us. "paper thin ribs" Their brains were a full 30% bigger than ours (forebrains + 50%). No brow ridge at all. Tiny teeth. Very prominent, sharp chin. Different in every way from the rugged Neanderthals. More aquatic....

 

F: I can’t comment on Strandloopers – I haven’t researched them yet. It sounds as though there are a mix of features. If they had gracile bones, they may have been surface swimmers rather than divers.

 

 just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. 

 

G: Precisely, then we obviously have more aquatic adaptations than any previous hominin who hadn't yet developed them. i.e we are the most aquatic (surviving) hominin.

 

F: Not losing a feature doesn’t mean it still serves its original function, especially if it is reduced. I repeat: we have smaller lungs, longer legs, lighter bones & shorter femora (better adapted to terrestrial locomotion than our ancestors), more globular crania, lower eyes, flatter faces (better when standing erect), smaller brains (less swimming in cold water, less seafood consumption, self-domestication-agriculture), we are probably less fat than Neanderthals (although they weren’t direct ancestors, we seem to have inherited our fat genes from them). Also, we cannot say that modern Homo sapiens – as a whole – is predominantly aquatic anymore. We retain some reduced aquatic features and tendencies. The whole point of the “Scars of Evolution” (E. Morgan) is that our scars are the remnants of a more aquatic past. Hardy and Morgan had it right. We were more aquatic in the past, but we can agree to disagree as everyone does here! 😊

 

QED.

 

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Tuesday, April 19, 2022 10:54 PM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

The climate I refer to from Miocene onwards is all supported by scientific research.

 

Yes. It's only the older stuff I decline to offer any opinions on.

 

 

There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel  

 

I have no problem with that.

 

 

 

 Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

 

Smaller, maybe. How do you determine tree climbing skills? In any case Australopiths were less aquatic than us and apparently are not considered ancestral to us anyway. This is all also predicated on the view that bipedalism is an aquatic adaptation. I don't think that was why it evolved originally.

 

There is evidence that Pan’s feet were once like ours

 

I have been looking long and hard and found nothing. This is quite important. I won't take it on trust. All the evidence (in utero, for instance) that I can find says the opposite.

 

 

 

I think you misunderstood me… there was only one reversal

 

Great. If there have been no reversals, then in what possible sense can we be less aquatic than we used to be?

 

 

I’m talking about Pan (chimps) not Homo.

 

The premise I thought we were discussing was the one about whether early Homo was more or less aquatic than us. Whether chimps reverted or not really doesn't have any bearing.

 

 

 

Thick brow ridges are great if you dive, browse and forage underwater... to push water away from the eyes

 

This is simply not true. I've mentioned katabatic flow to you before. When any fluid flows over a ridge it drives forcibly down the other side. Into your eyes in other words if it is a brow ridge. Here's a diagram of a "Chinook wind" to illustrate what happens.

 

 

"A 40- to 50-mph wind over the ridges and passes may reach speeds of 80 to 100 mph by the time the air reaches the foothills (on the other side)".



It therefore follows that losing the brow ridge makes for better underwater vision. The more aquatic Asian people have less of a brow ridge than westerners and modern Man has a more "streamlined" face than any previous ancestor. i.e. more aquatic.







Neanderthals were more aquatic than Homo sapiens. 

 

A bigger brain, I happily concede. However all the known big headed humanoids became extinct -- proto-Innuit, Boskop man, "coneheads", Neanderthals.... The fact that fewer and fewer females appeared over time suggests that heads became too big to pass through the birth canal, killing the mothers in childbirth. We are about on the sustainable limit, partly thanks to Caesarian sections. A reality that anthropologists manage to ignore, preferring to focus on how jolly intelligent they think they are.

 

Homo erectus had a tiny brain anyway. Are we to conclude then that he was less aquatic than us? Makes sense. We just can't have it both ways.

 

Big, heavy bones are really a huge handicap in the water if you think about it. Bad for swimming and floating. Good, on the way down, for diving. Coming up...  good for drowning. Manageable in sea water. Big problem in fresh. Neanderthal was robust because, like Australopithecus robustus, he was designed to live mostly on land and struggled to make a living in the water, not yet having our perfect neutral buoyancy and other modern refinements. Frequently fractured his skull diving in, apparently.

 

 

As you know I consider the most aquatic hominin ever was Strandlooper (Boskop man) -- extinct for only a few hundred years or so. If you look at all the (aquatic) features that distinguish us from earlier ancestors, Strandlooper had them all, but very much more so. We know they were fully dependent on marine resources, because to find even a blade of grass they would have had to cross both the Kalahari and the Namib deserts, the latter having existed for over 50 million years, and you can see their shell middens from many miles away.. 

 

They were more gracile than us. "paper thin ribs" Their brains were a full 30% bigger than ours (forebrains + 50%). No brow ridge at all. Tiny teeth. Very prominent, sharp chin. Different in every way from the rugged Neanderthals. More aquatic....

 

 

 just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. 

 

 

Precisely, then we obviously have more aquatic adaptations than any previous hominin who hadn't yet developed them. i.e we are the most aquatic (surviving) hominin.

 

QED.

 

G.

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 7:02 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Thanks, Gareth

Thanks, Francesca.

 

Would it be possible to reveal the source of this text

 

That would be me.  Email, subject "Second draft" about where when and how we became aquatic.

Ok, thanks. I’ll have another look for it.

 

 many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

Agreed. But they didn't spring up, fully formed overnight. They gradually improved, gradually increased in number and range of functions.

Agreed, that’s what I’ve been writing about.

 

I'm not making any guesses about what happened before the Miocene --  what the climate was like in some particular region, tectonic events, sea levels, vegetation, predators or the particular 'cause' of any specific change in physiology. For one thing I'm sure that none of these conditions remained unchanged for millions of years at any point, so too much of it is guesswork based on insufficient evidence. Almost anything could have happened somewhere at some point.

The climate I refer to from Miocene onwards is all supported by scientific research.

 

reversal from upright bipedalism towards arborealism

 

Not aware of any evidence for this "reversal". Not to say it couldn't or didn't happen, but if I ever knew of any evidence, I've forgotten.

There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel, from an already upright common ancestor, after splitting from a common ancestor. First they walked on 4 legs, then they walked on 2, then they walked on their knuckles.

Many of the australopithecines seem to become more arboreal over time, not less. Eg. Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

 

My only comments would be that, once we learned to throw, we were never able to brachiate again because of the change in orientation of our pectoral muscle.. Once we became bipedal, the loss of the divergent hallux meant we could never grasp a branch with our feet again. Not sure what kind of arborealism this would leave us. 

Humans didn’t become arboreal again, only Pan did. The point I’m trying to make is that the LCA was probably already a biped. After we split, the Pan line remained bipedal (wading, wetland foraging) for a while, but later, they returned to the forests, started climbing trees and walking on their knuckles when on the ground. There is evidence that Pan’s feet were once like ours (adducted halluces) but later their big toe moved round to the side and they could grasp branches again. (Pan foetus in utero).

 

 I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

We need to look at the other features that you consider reversals to see if any of them are aquatic features that we have lost since early Homo....

I think you misunderstood me… there was only one reversal I mentioned and that was in chimps…

 

You mention...

 

6 Ma: human-like foot morphology (loss of arborealism). -- Arborealism is definitely not aquatic.

That’s my point. We lost arboreal features because we became more aquatic. Or, because we became more aquatic, we lost arboreal climbing abilities.

 

5-2 Ma: Gradual reversal from upright bipedalism. -- Don't think I believe this (Open to persuasion. See above.) but anyway bipedalism is either not essentially aquatic, in which case it's irrelevant or it is, in which case we have become more aquatic (more upright), not less, since early Homo.

Yes, again, I think you’ve misunderstood me. Here I’m talking about Pan (chimps) not Homo. Reverse adaptations in evolution are more common even than first time adaptations. It happens all the time. It’s a result of gene expression. Once the gene exists, it can be switched on or off, according to need. That’s why snakes evolved legs, then lost them again. So did whales, etc. Chimp and human ancestors lost their fur, then chimps grew theirs again, but we didn’t. Early elephants lost their fur but woolly mammoths grew it back as they moved north. Some people are sometimes born with a tail, or webbing between their toes, because those genes still exist, even if silenced at the moment.

 

I think Homo is closer to the LCA in morphology than chimps. We haven’t changed as much as they have over the past 5-6 million years, and this is seen in their Y-chromosome. And most of those changes in chimps probably happened in the last million years or so, after they diverged from bonobos. Bonobos are more like us than chimps are (see picture attached).

 

2.0 Ma: Homo appears:  taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism, more sophisticated stone tool use, shellfish consumption. -- Other than the thick brow ridges (survival benefit not obvious to me) these all seem to be increases in aquatic adaptation.

Thick brow ridges are great if you dive, browse and forage underwater. Like a hooded nose, they act together to push water away from the eyes and nostrils as you move forward.
And yes, this is meant to demonstrate increases in aquatic adaptation. My point is, early Homo at 2 Ma was far more aquatic morphologically than H. sapiens is now.

 

300 ka to present: Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?) -- Again these seem to be evidence of a more aquatic lifestyle, not less.

Yes, Neanderthals were more aquatic than Homo sapiens. Again, that’s my point.

 

Which aquatic features do you think we have lost, then? What makes you think we are less well adapted to warm, cold, shallow, deep, clean, muddy, fresh or salt water than any of the less derived hominins? Your entire timeline seems perfectly to support my observation that aquatic adaptations have been a gradual, punctuated, cumulative process that has continued till today.

We haven’t fully lost any of those earlier adaptations (that we know of) but each is less pronounced. We have smaller thoraxes and reduced lung capacity compared to early Homo, as we don’t dive as much. We have lighter bones because we walk/run more, swim and dive less. We can’t see well underwater unless this skill is practised from childhood. We have less pronounced brow ridges for the same reason. We have rounder crania as we spend more time standing upright, whereas the more elongated crania of early Homo is better supported in a swimming, floating or diving position. We can swim and dive pretty well, for an ape, but not as well as erectus probably did. They may have been able to swim vast distances and dive to much deeper levels. They could probably hold their breath much longer than we can, or close to what professional / record holding divers can do now.

 

As your mum once wrote, just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. We would only lose it if keeping it was detrimental to our survival. We haven’t regrown our fur because we discovered clothes and central heating as an alternative means of keeping warm (and still get to go to the beach!) If we hadn’t, only the most hairy of us would survive in a colder climate to pass on our genes, so over time, our children would get hairier and hairier. We didn’t revert to quadrupedalism because by the time we became fully terrestrial again, our legs were much longer in relation to our arms and so the proportions were all wrong. Plus, we didn’t need to. By then we were quite comfortable moving around on 2 legs and using our forelimbs for other purposes. It’s served us quite well.

 

F.

G.

 

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 12:19 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Hi Gareth,

 

Would it be possible to reveal the source of this text, please? I’d like to read it.

 

I agree that climate has influenced anthropoid evolution at many stages and in different ways, although I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

If we look at the evidence, many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

[1st aquatic stage: Hominoidea]

30-25 Ma Climate: very hot, humid, subtropical forests; tectonic upheaval and rifting causing vast areas of East Africa to become flooded, creating forested islands in vast East African lakes.

25-20 Ma: orthograde body plan and modifications towards bipedal posture, suspensory adaptations of the wrist, hand, shoulders and arms, larger, wider thorax, loss of tail, etc.
20 – 14 Ma: gradual increase in size from small-bodied primates to large chimp sized apes

Some time between 25 Ma and 16 Ma: partial loss of pelage (great apes relative to macaques)

Overall increase in eccrine gland distribution (between OWMs and apes)

Probable reduction in olfactory ability

PNS

c. 18- 16 Ma Hylobatidae diverge

 

16-14 Ma: Climate: temperature decrease, reduced humidity & loss of biodiversity in Africa; increasing biodiversity, humid sub-tropical forests & vast bodies of water in Eurasia, land bridges between the two continents. Disappearance of most apes from Africa. Appearance of many ape species in Eurasia.

15 Ma: loss of uricase mutation and the ability to store sugars as fat

 

[Hominidae]

15-13 Ma: the ability to fashion stone tools

c. 15-14 Ma: Pongo diverges

14 Ma: plantigrade locomotion (quadrupedal)

12-11 Ma: loss of prognathism, robust jaws, postural bipedalism (wading)

11-9 Ma: Vallesian crisis causes the extinction of many apes (loss of forests, loss of edible fruits, spreading grasslands, seasonal food availability).

10-7 Ma: bipedal hominids roam the river valleys & great lakes of southern Europe & the Tethys-Med coasts.
Smaller, more thickly enamelled dentition – change of diet.

 

[Homininae]

10-6 Ma: terrestrial bipedalism develops

c. 10-8 Ma: gorilla divergence

7 Ma: human-like P4 dental root morphology

6 Ma: human-like foot morphology (loss of arborealism)

 

6-5 Ma: Pan / Homo diverge

5.9 – 5.3 Ma: Mediterranean Salinity Crisis: great unidirectional migrations of fauna away from the southern Med, towards Africa.

5.3 Ma: Zanclean Megaflood cuts off land bridge between Eurasia and Africa.

Pliocene: 5.3 – 2.6 Ma. Sea-levels rise by up to 30 m. Hyper aridity in the Arabian Peninsula prevents migration of fauna eastwards.

During much of this period, the Arabian Peninsula is effectively cut off from the rest of the world.

 

4-3 Ma (PTERV1 virus throughout Africa, affects all African apes, but not Homo or Orangutans)

 

[Panini / Australopithecines]

Climate: Loss of forests and wetlands, increase of savannah and mosaic environments

5-2 Ma: Gradual reversal from upright bipedalism towards arborealism, and eventually, knucklewalking (also in Gorilla – homoplasy).

 

[Early Homo]

2.6 – 2.0 Ma: Pleistocene cooling, sea-level decrease, vast intercontinental shelves appear, land bridges, intertidal zones, migration routes

2.0 Ma: Homo appears: taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism
More sophisticated stone tool use, shellfish consumption.

 

[Later Homo]

2.6 Ma – 2.0 Ka: Pleistocene cooling, sea-level decrease, fluctuating temperatures (between glacials).

Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?)

 

[Homo sapiens]

300 Ka – present: Holocene (relatively stable climate, less overall humidity)

More gracile forms (taller, thinner – like waders), rounder crania, shorter femoral necks (adaptation for running). Loss of platycephaly, heavy brow-ridges, elongated crania. Brain capacity reduction, flatter faces, smaller teeth, smaller noses, lighter bones, smaller thoracic capacity,

Suggests H. sapiens was more terrestrial than earlier Homo.

 

Present – future? Anthropocene: Global warming, global climate fluctuations, sea-level rise, mass extinction events…where next?

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 18, 2022 10:57 AM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Homo sapiens is, if anything, more aquatic than Homo erectus.

 

 

"As far back as 17 March 1960, Professor Sir Alister Hardy noted in The New Scientist that modern humans have many features that suggest an aquatic phase in our evolution at some time in the distant past.  

The assumption was that a group of primates became isolated on an island or some other inaccessible waterside environment and survived by becoming adapted to a semi-aquatic lifestyle in the course of that single evolutionary event. Subsequent discoveries have provided data that both support and contradict that hypothesis. 

The present investigation proposes an alternative model whereby, over millions of years, a series of emergencies, in the shape of climate fluctuations, from fertile to desert conditions and coinciding with glacial and interglacial epochs, repeatedly imposed very stringent survival pressures on every group of hominids. From the late Miocene onward, scores of such events dictated the selection criteria for gradual adaptation to an opportunistic aquatic diet in a punctuated series of evolutionary steps. 

These adaptations were cumulative, and the fossil record includes progressively more numerous examples of each new version of pre-human and human with the passage of time, progressively larger deposits of bivalve shells and other edible aquatic food species in shell middens, and more widely distributed locations for the stone tools needed to process them efficiently. 

This interpretation of the available evidence satisfies all the significant objections to Hardy’s theory and leads to the conclusion that, physiologically, we are more aquatic now than we have ever been, and the astonishing current world records for breath holding and free diving would seem to support that view."

 

The idea of a single, brief isolation event producing all (or any) of our aquatic adaptations was never really credible.

G.   

 


From: AAT@groups.io <AAT@groups.io> on behalf of algiskuliukas <algis@...>
Sent: Monday, April 18, 2022 10:07 AM
To: AAT@groups.io <AAT@groups.io>
Subject: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

For those of us who are open minded enough to answer Hardy's question "Was Man More Aquatic in the Past?" with a cautious affirmative, a second question follows "If, so when was that and how much?"

Having thought about this for twenty-five years and studied human evolution (MSc from UCL with distinction and PhD in human bipedal origins from UWA) I have come to the conclusion that the answer to the second question should be "very early modern Homo sapiens ca 200,000 years ago or so"... and... "not much".

Some proponents (e.g. Marc Verhaegen and Stephen Munro) would argue that a better answer would be "Homo erectus (sensu stricto) - i.e. the Asian, rather than African forms" and "that they were predominantly bottom divers."

That's quite a difference.

So, I'd like to discuss this openly to see if I have missed something. 

Let me start the ball rolling...

Marc always cites pacheostosis (heavy bones) of H. erectus as leaving "no other possibility" than bottom diving for this hominin but were their bones really that heavy? If you look at the Nariokotome boy femur, for example, it is remarkably gracile. Where are the papers in the literature that backs up this claim?

Marc also cites their pelvic shape as being platypelloid, with long femoral necks as further evidence but, again, that's not what I see in the literature. Nariokotome boy's pelvis is remarkably narrow actually, android rather than platypelloid. In any case what his platypelloidy got to do with bottom diving? Dugongs/manatees do not share this convergence. Their pelves, appear to be on their way to becoming vestigial like cetacea.

Whether they had heavy bones or not, there is undeniable evidence of significant weight bearing in the bones of Homo erectus. The tibial plate, the oval shaped distal femoral condyles, the robust femoral head, the large acetabulae with superiorly orientated lunate surface. The robust sacral body and large lumbar vertebrae all speak of an upright, walking, terrestrial striding biped - just like us. They seem to have been predominantly striding bipeds, not divers.

Please don't misunderstand me. I am not suggesting that Homo erectus did not swim or dive - just that they didn't do so very much, and specifically, not as much as we modern human did, or still do.

When Homo erectus reached the islands of Java and Flores some 1.8 million years ago, they could have done so without getting their feet wet as the current archipelago of Indonesia has been connected via land bridges from time to time. Of course, I have no doubt they often went swimming and diving in coastal shallows but, if they were as adept as Marc suggests (a predominantly bottom diver, remember) then it is remarkable that the narrow strait of water between Bali and Lombok across the Wallace line, just 20km wide, was never crossed by these diving hominins in 1.8 million years. If they did cross, they would have certainly populated the whole of the Australasian continent as that too was all joined by land at various times since. And yet we so no evidence of any human like species in Australia until 60,000 ago or so.

I must remind that modern humans regularly swim across such stretches of open water. The Perth - Rottnest swim is run every year and has thousands of participants. (https://en.wikipedia.org/wiki/Rottnest_Channel_Swim#:~:text=The%20distance%20is%2019.7%20km,teams%20of%20two%20or%20four.) It is about the same distance as Bali - Lombok via Penida. And of course far greater distances have been crossed than that, such as the Channel between England and France.

Of course, absence of evidence is not evidence of absence but, it seems to me that if we are to remain true to scientific principles we must base our ideas on evidence and here, the evidence is that Homo sapiens is, if anything, more aquatic than Homo erectus.

Algis Kuliukas
Perth
April 2022



[i] Carlson, K., et al.: The pectoral girdle of StW 573 ("Little Foot") and its implications for shoulder evolution in the Hominina. cs 2021 JHE in press. https://doi.org/10.1016/j.jhevol.2021.102983

[ii] Christine M. Harper, Christopher B. Ruff, Adam D. Sylvester, Calcaneal shape variation in humans, nonhuman primates, and early hominins, Journal of Human Evolution, Volume 159, 2021, 103050,

ISSN 0047-2484, https://doi.org/10.1016/j.jhevol.2021.103050. (https://www.sciencedirect.com/science/article/pii/S0047248421001020)

[iii] DeSilva, J, McNutt, E, Benoit, J, Zipfel, B. One small step: A review of Plio-Pleistocene hominin foot evolution. Am J Phys Anthropol. 2019; 168:S67: 63– 140. https://doi.org/10.1002/ajpa.23750

[iv] Rightmire GP. Homo erectus and Middle Pleistocene hominins: brain size, skull form, and species recognition. J Hum Evol. 2013 Sep;65(3):223-52. doi: 10.1016/j.jhevol.2013.04.008. Epub 2013 Jul 10. PMID: 23850294.

[v] Antón, S. C.; Taboada, H. G.; et al. (2016). "Morphological variation in Homo erectus and the origins of developmental plasticity". Philosophical Transactions of the Royal Society B. 371 (1698): 20150236. doi:10.1098/rstb.2015.0236. PMC 4920293. PMID 27298467.

[vi] Alexandra Houssaye, P. Martin Sander, Nicole Klein, Adaptive Patterns in Aquatic Amniote Bone Microanatomy—More Complex than Previously Thought, Integrative and Comparative Biology, Volume 56, Issue 6, December 2016, Pages 1349–1369, https://doi.org/10.1093/icb/icw120


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

fceska_gr
 

G: How do you determine tree climbing skills? In any case Australopiths were less aquatic than us and apparently are not considered ancestral to us anyway. This is all also predicated on the view that bipedalism is an aquatic adaptation. I don't think that was why it evolved originally.

 

F: “Many of the same features seen in australopithecines in Africa that are often cited as an indication of a species belonging to the human lineage, such as an anteriorly situated foramen magnum, short but broad ilia, relatively small canines, etc., are also found in many of the fossil apes from Europe (Wood & Harrison, 2011). Furthermore, if a taxon displays features both for bipedalism and arboreal climbing, it is traditionally understood to imply that the species is somehow transitional between a more arboreal earlier form and a later more terrestrial form, when it could just as easily have been going the other way. Evidence shows that some late australopithecines, such as Australopithecus sediba from 1.98 Ma, were more arboreal than earlier australopithecines, such as Australopithecus afarensis (Rein, et al., 2017*). The same could be said regarding brain sizes as we quite often see that the later australopithecines had smaller cranial capacities than earlier fossils. For example, from East Africa, the younger Paranthropus aethiopicus (2.7-2.3 Ma) had a cranium (c. 410 cc) falling within the range of the much older A. afarensis (c. 375-550 cc) at 3.9-2.9 Ma; while in South Africa, at 1. 98 Ma, A. sediba’s cranium was 420-450 cc and therefore smaller than A. prometheus’s cranium (500-520 cc) was already at 3.67 Ma. Although we are not claiming a direct line through any of these species, there is no clear trend showing that australopithecines were becoming more Homo-like over time.”

“Researchers compared A. prometheus’s shoulder to apes, hominins and humans and found that Little Foot was adapted to living partially in the trees and partially on the ground. As well as relatively long legs and limited bipedal foot morphology, it had a long, curved clavicle and dorsally positioned scapula with a high ridge to attach heavy muscles, ideal for supporting its weight below branch, more similar to that seen in arboreal apes, such as chimpanzees. They concluded that “the arm of our ancestors at 3.67 Ma was still (my emphasis) being used to bear substantial weight during arboreal movements in trees, for climbing or hanging beneath branches.” [i] The assumption here is that this is a retained feature from a more primitive ancestor, rather than the expression of an earlier adaptation as a result of returning to the trees.”

“In a recent paper, scientists revealed the results of a study in which they compared the heel bones (calcanei) of humans, extant apes and various hominin fossils. They found that earlier Australopithecus species, such as Lucy’s, had a heelbone more similar to humans than apes, better to support their weight on two legs, while later apiths had more ape-like heelbones, suggesting a reversal over time from bipedalism to arborealism.[ii] Other researchers studying hominin foot evolution have suggested that the similarities between A.afarensis’ feet and human feet might imply that they both “descend from a common ancestor with a similarly derived foot” and that “the large calcaneal tuber (heel bone) is obtained in developmentally different ways in A. afarensis and in modern humans.”[iii] In other words, homoplasy.

 

*Adaptation to suspensory locomotion in Australopithecus sediba

https://www.sciencedirect.com/science/article/abs/pii/S0047248416302743

 

(I’m not claiming bipedalism is strictly aquatic, although I do think it emerged out of orthograde apes wading in wetlands in the first instance. And I don’t believe australopithecines are ancestral to us, but ancestral to the African apes, which is the point I’m making here).

 

There is evidence that Pan’s feet were once like ours

 

G: I have been looking long and hard and found nothing. This is quite important. I won't take it on trust. All the evidence (in utero, for instance) that I can find says the opposite.

 

F: Marc has always referenced C. S. Coon for this, but I haven’t been able to find the direct source. However, in another paper I found this (with no reference).

 

“The marked abductability of the chimpanzee hallux is probably a derived condition within the human/African ape clade. Indeed, embryos of chimpanzees have an adducted hallux suggesting that relative adduction could be the LCA primitive condition…”
Meldrum, Jeff & Sarmiento, Esteban. (2018). Comments on possible Miocene hominin footprints. Proceedings of the Geologists' Association. 129. 10.1016/j.pgeola.2018.05.006.

 

Also, Schultz, 1925 noted – although he doesn’t say at what stage this happens in chimpanzees…


“In all primates the great toe is found to branch from the sole, just at the base of the second toe, in very early growth stages. This embryonic position is retained throughout life in man, whereas in all other primates the place of attachment of the great toe shifts proximally, similar to the ontogenetic shifting in the attachment of the thumb to the palm from the base of the index finger to a place nearer the wrist. In the gorilla this shifting of the hallux is least pronounced of any of the apes, whereas it is most extreme in the orang, a greater difference existing in this respect between the latter and gorilla than between gorilla and man (fig. 16). Other propor tions on the foot lead to similar conclusions…”

https://www.jstor.org/stable/pdf/24527371.pdf

 

G: If there have been no reversals, then in what possible sense can we be less aquatic than we used to be?

 

F: There are many ways. Read the paragraph I wrote further down about ‘reduction’ of features (smaller lungs, etc.), and this is only from fossil evidence, which is very limited, and based on comparative anatomy with other species, so we can’t really know what other features we may have fully lost. Maybe we did have webbing between our fingers & toes… (!!)

 

I’m talking about Pan (chimps) not Homo.

 

G: The premise I thought we were discussing was the one about whether early Homo was more or less aquatic than us. Whether chimps reverted or not really doesn't have any bearing.

 

F: Yes, we were, but earlier we were also talking about climate and how it instigated evolutionary changes. I included a small two-line reference to Panins to suggest why the australopithecines may have become more arboreal as the African wetlands dried up.

 

Thick brow ridges are great if you dive, browse and forage underwater... to push water away from the eyes

G: This is simply not true. I've mentioned katabatic flow to you before. When any fluid flows over a ridge it drives forcibly down the other side. Into your eyes in other words if it is a brow ridge.

 

F: I’m not convinced by this but clearly more research is needed. I suppose it is testable. The example you give is based on air, not water, and presumes a straight directional flow over the ridge. I believe the brows on a hominin, face down in water, would divert the flow of water away to the sides of the face. Maybe it’s not so much to do with swimming but even surfacing regularly to breathe. With a flat face and no brows the water would just pour straight down into your gasping mouth. In general, our brows are thought to be useful in diverting sweat from flowing into our eyes, so the same principle is true, but just with more water, more regularly.

 

And how do you get “more aquatic” Asian people? Some are, of course, if you’re thinking of Moken, etc. or Japanese pearl divers, but can we say Asians are more aquatic. We are all still H.sapiens.

 

Neanderthals were more aquatic than Homo sapiens. 

 

G: A bigger brain, I happily concede. However all the known big headed humanoids became extinct -- proto-Innuit, Boskop man, "coneheads", Neanderthals.... The fact that fewer and fewer females appeared over time suggests that heads became too big to pass through the birth canal, killing the mothers in childbirth. We are about on the sustainable limit, partly thanks to Caesarian sections. A reality that anthropologists manage to ignore, preferring to focus on how jolly intelligent they think they are.

 

F: Is that a fact? Do you have a reference? We don’t know why Neanderthals went extinct. Many reasons are proposed.

 

G: Homo erectus had a tiny brain anyway. Are we to conclude then that he was less aquatic than us? Makes sense. We just can't have it both ways.

 

F: Homo erectus’ brain capacity, with an average of 950cc, [iv] ranged from 550cc in some early samples, to 1251 cc,[v] which is close to that found in modern humans. (I personally believe that brain size increase is a result of marine-chain based nutrients + cold water, which explains the size increase as the climate got cooler. Neanderthals with the largest brains, swam in the cold waters of the Atlantic. Only a more aquatic species would do that regularly, don’t you think?).

 

G: Big, heavy bones are really a huge handicap in the water if you think about it. Bad for swimming and floating. Good, on the way down, for diving. Coming up...  good for drowning. Manageable in sea water. Big problem in fresh. Neanderthal was robust because, like Australopithecus robustus, he was designed to live mostly on land and struggled to make a living in the water, not yet having our perfect neutral buoyancy and other modern refinements. Frequently fractured his skull diving in, apparently.

 

F: “In the animal kingdom, good runners tend to be gracile, or lightly built, (e.g., cheetahs, antelopes, horses, greyhounds), and even floating semi-aquatic animals such as ducks have light bones. Conversely, dense, heavy bones tend to be brittle and not suitable for fast or sustained terrestrial locomotion. As noted by Alexandra Houssaye, et al, in their study of amniote bone microanatomy regarding thick cortical bones: “These rather well-known specializations are considered incompatible with a terrestrial locomotion and generally do not occur (or incipiently so) in terrestrial taxa… or even in most semi-aquatic taxa.” In contrast, bone mass increase is found “in almost all highly or exclusively aquatic amniotes foraging below the water surface.[vi]

 

Seems quite clear to me that both erectus and Neanderthals, with their heavier, more robust bones, were better suited to shallow diving and totally incompatible with running. And possibly why women have more fat then men (males may have been deeper divers) and why women gain fat & lose bone density after menopause when they have to be floating around at the surface with the grandkids.

 

G: As you know I consider the most aquatic hominin ever was Strandlooper (Boskop man) -- extinct for only a few hundred years or so. If you look at all the (aquatic) features that distinguish us from earlier ancestors, Strandlooper had them all, but very much more so. We know they were fully dependent on marine resources, because to find even a blade of grass they would have had to cross both the Kalahari and the Namib deserts, the latter having existed for over 50 million years, and you can see their shell middens from many miles away.. 

 

They were more gracile than us. "paper thin ribs" Their brains were a full 30% bigger than ours (forebrains + 50%). No brow ridge at all. Tiny teeth. Very prominent, sharp chin. Different in every way from the rugged Neanderthals. More aquatic....

 

F: I can’t comment on Strandloopers – I haven’t researched them yet. It sounds as though there are a mix of features. If they had gracile bones, they may have been surface swimmers rather than divers.

 

 just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. 

 

G: Precisely, then we obviously have more aquatic adaptations than any previous hominin who hadn't yet developed them. i.e we are the most aquatic (surviving) hominin.

 

F: Not losing a feature doesn’t mean it still serves its original function, especially if it is reduced. I repeat: we have smaller lungs, longer legs, lighter bones & shorter femora (better adapted to terrestrial locomotion than our ancestors), more globular crania, lower eyes, flatter faces (better when standing erect), smaller brains (less swimming in cold water, less seafood consumption, self-domestication-agriculture), we are probably less fat than Neanderthals (although they weren’t direct ancestors, we seem to have inherited our fat genes from them). Also, we cannot say that modern Homo sapiens – as a whole – is predominantly aquatic anymore. We retain some reduced aquatic features and tendencies. The whole point of the “Scars of Evolution” (E. Morgan) is that our scars are the remnants of a more aquatic past. Hardy and Morgan had it right. We were more aquatic in the past, but we can agree to disagree as everyone does here! 😊

 

QED.

 

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Tuesday, April 19, 2022 10:54 PM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

The climate I refer to from Miocene onwards is all supported by scientific research.

 

Yes. It's only the older stuff I decline to offer any opinions on.

 

 

There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel  

 

I have no problem with that.

 

 

 

 Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

 

Smaller, maybe. How do you determine tree climbing skills? In any case Australopiths were less aquatic than us and apparently are not considered ancestral to us anyway. This is all also predicated on the view that bipedalism is an aquatic adaptation. I don't think that was why it evolved originally.

 

There is evidence that Pan’s feet were once like ours

 

I have been looking long and hard and found nothing. This is quite important. I won't take it on trust. All the evidence (in utero, for instance) that I can find says the opposite.

 

 

 

I think you misunderstood me… there was only one reversal

 

Great. If there have been no reversals, then in what possible sense can we be less aquatic than we used to be?

 

 

I’m talking about Pan (chimps) not Homo.

 

The premise I thought we were discussing was the one about whether early Homo was more or less aquatic than us. Whether chimps reverted or not really doesn't have any bearing.

 

 

 

Thick brow ridges are great if you dive, browse and forage underwater... to push water away from the eyes

 

This is simply not true. I've mentioned katabatic flow to you before. When any fluid flows over a ridge it drives forcibly down the other side. Into your eyes in other words if it is a brow ridge. Here's a diagram of a "Chinook wind" to illustrate what happens.

 

 

"A 40- to 50-mph wind over the ridges and passes may reach speeds of 80 to 100 mph by the time the air reaches the foothills (on the other side)".



It therefore follows that losing the brow ridge makes for better underwater vision. The more aquatic Asian people have less of a brow ridge than westerners and modern Man has a more "streamlined" face than any previous ancestor. i.e. more aquatic.







Neanderthals were more aquatic than Homo sapiens. 

 

A bigger brain, I happily concede. However all the known big headed humanoids became extinct -- proto-Innuit, Boskop man, "coneheads", Neanderthals.... The fact that fewer and fewer females appeared over time suggests that heads became too big to pass through the birth canal, killing the mothers in childbirth. We are about on the sustainable limit, partly thanks to Caesarian sections. A reality that anthropologists manage to ignore, preferring to focus on how jolly intelligent they think they are.

 

Homo erectus had a tiny brain anyway. Are we to conclude then that he was less aquatic than us? Makes sense. We just can't have it both ways.

 

Big, heavy bones are really a huge handicap in the water if you think about it. Bad for swimming and floating. Good, on the way down, for diving. Coming up...  good for drowning. Manageable in sea water. Big problem in fresh. Neanderthal was robust because, like Australopithecus robustus, he was designed to live mostly on land and struggled to make a living in the water, not yet having our perfect neutral buoyancy and other modern refinements. Frequently fractured his skull diving in, apparently.

 

 

As you know I consider the most aquatic hominin ever was Strandlooper (Boskop man) -- extinct for only a few hundred years or so. If you look at all the (aquatic) features that distinguish us from earlier ancestors, Strandlooper had them all, but very much more so. We know they were fully dependent on marine resources, because to find even a blade of grass they would have had to cross both the Kalahari and the Namib deserts, the latter having existed for over 50 million years, and you can see their shell middens from many miles away.. 

 

They were more gracile than us. "paper thin ribs" Their brains were a full 30% bigger than ours (forebrains + 50%). No brow ridge at all. Tiny teeth. Very prominent, sharp chin. Different in every way from the rugged Neanderthals. More aquatic....

 

 

 just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. 

 

 

Precisely, then we obviously have more aquatic adaptations than any previous hominin who hadn't yet developed them. i.e we are the most aquatic (surviving) hominin.

 

QED.

 

G.

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 7:02 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Thanks, Gareth

Thanks, Francesca.

 

Would it be possible to reveal the source of this text

 

That would be me.  Email, subject "Second draft" about where when and how we became aquatic.

Ok, thanks. I’ll have another look for it.

 

 many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

Agreed. But they didn't spring up, fully formed overnight. They gradually improved, gradually increased in number and range of functions.

Agreed, that’s what I’ve been writing about.

 

I'm not making any guesses about what happened before the Miocene --  what the climate was like in some particular region, tectonic events, sea levels, vegetation, predators or the particular 'cause' of any specific change in physiology. For one thing I'm sure that none of these conditions remained unchanged for millions of years at any point, so too much of it is guesswork based on insufficient evidence. Almost anything could have happened somewhere at some point.

The climate I refer to from Miocene onwards is all supported by scientific research.

 

reversal from upright bipedalism towards arborealism

 

Not aware of any evidence for this "reversal". Not to say it couldn't or didn't happen, but if I ever knew of any evidence, I've forgotten.

There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel, from an already upright common ancestor, after splitting from a common ancestor. First they walked on 4 legs, then they walked on 2, then they walked on their knuckles.

Many of the australopithecines seem to become more arboreal over time, not less. Eg. Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

 

My only comments would be that, once we learned to throw, we were never able to brachiate again because of the change in orientation of our pectoral muscle.. Once we became bipedal, the loss of the divergent hallux meant we could never grasp a branch with our feet again. Not sure what kind of arborealism this would leave us. 

Humans didn’t become arboreal again, only Pan did. The point I’m trying to make is that the LCA was probably already a biped. After we split, the Pan line remained bipedal (wading, wetland foraging) for a while, but later, they returned to the forests, started climbing trees and walking on their knuckles when on the ground. There is evidence that Pan’s feet were once like ours (adducted halluces) but later their big toe moved round to the side and they could grasp branches again. (Pan foetus in utero).

 

 I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

We need to look at the other features that you consider reversals to see if any of them are aquatic features that we have lost since early Homo....

I think you misunderstood me… there was only one reversal I mentioned and that was in chimps…

 

You mention...

 

6 Ma: human-like foot morphology (loss of arborealism). -- Arborealism is definitely not aquatic.

That’s my point. We lost arboreal features because we became more aquatic. Or, because we became more aquatic, we lost arboreal climbing abilities.

 

5-2 Ma: Gradual reversal from upright bipedalism. -- Don't think I believe this (Open to persuasion. See above.) but anyway bipedalism is either not essentially aquatic, in which case it's irrelevant or it is, in which case we have become more aquatic (more upright), not less, since early Homo.

Yes, again, I think you’ve misunderstood me. Here I’m talking about Pan (chimps) not Homo. Reverse adaptations in evolution are more common even than first time adaptations. It happens all the time. It’s a result of gene expression. Once the gene exists, it can be switched on or off, according to need. That’s why snakes evolved legs, then lost them again. So did whales, etc. Chimp and human ancestors lost their fur, then chimps grew theirs again, but we didn’t. Early elephants lost their fur but woolly mammoths grew it back as they moved north. Some people are sometimes born with a tail, or webbing between their toes, because those genes still exist, even if silenced at the moment.

 

I think Homo is closer to the LCA in morphology than chimps. We haven’t changed as much as they have over the past 5-6 million years, and this is seen in their Y-chromosome. And most of those changes in chimps probably happened in the last million years or so, after they diverged from bonobos. Bonobos are more like us than chimps are (see picture attached).

 

2.0 Ma: Homo appears:  taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism, more sophisticated stone tool use, shellfish consumption. -- Other than the thick brow ridges (survival benefit not obvious to me) these all seem to be increases in aquatic adaptation.

Thick brow ridges are great if you dive, browse and forage underwater. Like a hooded nose, they act together to push water away from the eyes and nostrils as you move forward.
And yes, this is meant to demonstrate increases in aquatic adaptation. My point is, early Homo at 2 Ma was far more aquatic morphologically than H. sapiens is now.

 

300 ka to present: Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?) -- Again these seem to be evidence of a more aquatic lifestyle, not less.

Yes, Neanderthals were more aquatic than Homo sapiens. Again, that’s my point.

 

Which aquatic features do you think we have lost, then? What makes you think we are less well adapted to warm, cold, shallow, deep, clean, muddy, fresh or salt water than any of the less derived hominins? Your entire timeline seems perfectly to support my observation that aquatic adaptations have been a gradual, punctuated, cumulative process that has continued till today.

We haven’t fully lost any of those earlier adaptations (that we know of) but each is less pronounced. We have smaller thoraxes and reduced lung capacity compared to early Homo, as we don’t dive as much. We have lighter bones because we walk/run more, swim and dive less. We can’t see well underwater unless this skill is practised from childhood. We have less pronounced brow ridges for the same reason. We have rounder crania as we spend more time standing upright, whereas the more elongated crania of early Homo is better supported in a swimming, floating or diving position. We can swim and dive pretty well, for an ape, but not as well as erectus probably did. They may have been able to swim vast distances and dive to much deeper levels. They could probably hold their breath much longer than we can, or close to what professional / record holding divers can do now.

 

As your mum once wrote, just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. We would only lose it if keeping it was detrimental to our survival. We haven’t regrown our fur because we discovered clothes and central heating as an alternative means of keeping warm (and still get to go to the beach!) If we hadn’t, only the most hairy of us would survive in a colder climate to pass on our genes, so over time, our children would get hairier and hairier. We didn’t revert to quadrupedalism because by the time we became fully terrestrial again, our legs were much longer in relation to our arms and so the proportions were all wrong. Plus, we didn’t need to. By then we were quite comfortable moving around on 2 legs and using our forelimbs for other purposes. It’s served us quite well.

 

F.

G.

 

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 12:19 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Hi Gareth,

 

Would it be possible to reveal the source of this text, please? I’d like to read it.

 

I agree that climate has influenced anthropoid evolution at many stages and in different ways, although I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

If we look at the evidence, many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

[1st aquatic stage: Hominoidea]

30-25 Ma Climate: very hot, humid, subtropical forests; tectonic upheaval and rifting causing vast areas of East Africa to become flooded, creating forested islands in vast East African lakes.

25-20 Ma: orthograde body plan and modifications towards bipedal posture, suspensory adaptations of the wrist, hand, shoulders and arms, larger, wider thorax, loss of tail, etc.
20 – 14 Ma: gradual increase in size from small-bodied primates to large chimp sized apes

Some time between 25 Ma and 16 Ma: partial loss of pelage (great apes relative to macaques)

Overall increase in eccrine gland distribution (between OWMs and apes)

Probable reduction in olfactory ability

PNS

c. 18- 16 Ma Hylobatidae diverge

 

16-14 Ma: Climate: temperature decrease, reduced humidity & loss of biodiversity in Africa; increasing biodiversity, humid sub-tropical forests & vast bodies of water in Eurasia, land bridges between the two continents. Disappearance of most apes from Africa. Appearance of many ape species in Eurasia.

15 Ma: loss of uricase mutation and the ability to store sugars as fat

 

[Hominidae]

15-13 Ma: the ability to fashion stone tools

c. 15-14 Ma: Pongo diverges

14 Ma: plantigrade locomotion (quadrupedal)

12-11 Ma: loss of prognathism, robust jaws, postural bipedalism (wading)

11-9 Ma: Vallesian crisis causes the extinction of many apes (loss of forests, loss of edible fruits, spreading grasslands, seasonal food availability).

10-7 Ma: bipedal hominids roam the river valleys & great lakes of southern Europe & the Tethys-Med coasts.
Smaller, more thickly enamelled dentition – change of diet.

 

[Homininae]

10-6 Ma: terrestrial bipedalism develops

c. 10-8 Ma: gorilla divergence

7 Ma: human-like P4 dental root morphology

6 Ma: human-like foot morphology (loss of arborealism)

 

6-5 Ma: Pan / Homo diverge

5.9 – 5.3 Ma: Mediterranean Salinity Crisis: great unidirectional migrations of fauna away from the southern Med, towards Africa.

5.3 Ma: Zanclean Megaflood cuts off land bridge between Eurasia and Africa.

Pliocene: 5.3 – 2.6 Ma. Sea-levels rise by up to 30 m. Hyper aridity in the Arabian Peninsula prevents migration of fauna eastwards.

During much of this period, the Arabian Peninsula is effectively cut off from the rest of the world.

 

4-3 Ma (PTERV1 virus throughout Africa, affects all African apes, but not Homo or Orangutans)

 

[Panini / Australopithecines]

Climate: Loss of forests and wetlands, increase of savannah and mosaic environments

5-2 Ma: Gradual reversal from upright bipedalism towards arborealism, and eventually, knucklewalking (also in Gorilla – homoplasy).

 

[Early Homo]

2.6 – 2.0 Ma: Pleistocene cooling, sea-level decrease, vast intercontinental shelves appear, land bridges, intertidal zones, migration routes

2.0 Ma: Homo appears: taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism
More sophisticated stone tool use, shellfish consumption.

 

[Later Homo]

2.6 Ma – 2.0 Ka: Pleistocene cooling, sea-level decrease, fluctuating temperatures (between glacials).

Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?)

 

[Homo sapiens]

300 Ka – present: Holocene (relatively stable climate, less overall humidity)

More gracile forms (taller, thinner – like waders), rounder crania, shorter femoral necks (adaptation for running). Loss of platycephaly, heavy brow-ridges, elongated crania. Brain capacity reduction, flatter faces, smaller teeth, smaller noses, lighter bones, smaller thoracic capacity,

Suggests H. sapiens was more terrestrial than earlier Homo.

 

Present – future? Anthropocene: Global warming, global climate fluctuations, sea-level rise, mass extinction events…where next?

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 18, 2022 10:57 AM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Homo sapiens is, if anything, more aquatic than Homo erectus.

 

 

"As far back as 17 March 1960, Professor Sir Alister Hardy noted in The New Scientist that modern humans have many features that suggest an aquatic phase in our evolution at some time in the distant past.  

The assumption was that a group of primates became isolated on an island or some other inaccessible waterside environment and survived by becoming adapted to a semi-aquatic lifestyle in the course of that single evolutionary event. Subsequent discoveries have provided data that both support and contradict that hypothesis. 

The present investigation proposes an alternative model whereby, over millions of years, a series of emergencies, in the shape of climate fluctuations, from fertile to desert conditions and coinciding with glacial and interglacial epochs, repeatedly imposed very stringent survival pressures on every group of hominids. From the late Miocene onward, scores of such events dictated the selection criteria for gradual adaptation to an opportunistic aquatic diet in a punctuated series of evolutionary steps. 

These adaptations were cumulative, and the fossil record includes progressively more numerous examples of each new version of pre-human and human with the passage of time, progressively larger deposits of bivalve shells and other edible aquatic food species in shell middens, and more widely distributed locations for the stone tools needed to process them efficiently. 

This interpretation of the available evidence satisfies all the significant objections to Hardy’s theory and leads to the conclusion that, physiologically, we are more aquatic now than we have ever been, and the astonishing current world records for breath holding and free diving would seem to support that view."

 

The idea of a single, brief isolation event producing all (or any) of our aquatic adaptations was never really credible.

G.   

 


From: AAT@groups.io <AAT@groups.io> on behalf of algiskuliukas <algis@...>
Sent: Monday, April 18, 2022 10:07 AM
To: AAT@groups.io <AAT@groups.io>
Subject: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

For those of us who are open minded enough to answer Hardy's question "Was Man More Aquatic in the Past?" with a cautious affirmative, a second question follows "If, so when was that and how much?"

Having thought about this for twenty-five years and studied human evolution (MSc from UCL with distinction and PhD in human bipedal origins from UWA) I have come to the conclusion that the answer to the second question should be "very early modern Homo sapiens ca 200,000 years ago or so"... and... "not much".

Some proponents (e.g. Marc Verhaegen and Stephen Munro) would argue that a better answer would be "Homo erectus (sensu stricto) - i.e. the Asian, rather than African forms" and "that they were predominantly bottom divers."

That's quite a difference.

So, I'd like to discuss this openly to see if I have missed something. 

Let me start the ball rolling...

Marc always cites pacheostosis (heavy bones) of H. erectus as leaving "no other possibility" than bottom diving for this hominin but were their bones really that heavy? If you look at the Nariokotome boy femur, for example, it is remarkably gracile. Where are the papers in the literature that backs up this claim?

Marc also cites their pelvic shape as being platypelloid, with long femoral necks as further evidence but, again, that's not what I see in the literature. Nariokotome boy's pelvis is remarkably narrow actually, android rather than platypelloid. In any case what his platypelloidy got to do with bottom diving? Dugongs/manatees do not share this convergence. Their pelves, appear to be on their way to becoming vestigial like cetacea.

Whether they had heavy bones or not, there is undeniable evidence of significant weight bearing in the bones of Homo erectus. The tibial plate, the oval shaped distal femoral condyles, the robust femoral head, the large acetabulae with superiorly orientated lunate surface. The robust sacral body and large lumbar vertebrae all speak of an upright, walking, terrestrial striding biped - just like us. They seem to have been predominantly striding bipeds, not divers.

Please don't misunderstand me. I am not suggesting that Homo erectus did not swim or dive - just that they didn't do so very much, and specifically, not as much as we modern human did, or still do.

When Homo erectus reached the islands of Java and Flores some 1.8 million years ago, they could have done so without getting their feet wet as the current archipelago of Indonesia has been connected via land bridges from time to time. Of course, I have no doubt they often went swimming and diving in coastal shallows but, if they were as adept as Marc suggests (a predominantly bottom diver, remember) then it is remarkable that the narrow strait of water between Bali and Lombok across the Wallace line, just 20km wide, was never crossed by these diving hominins in 1.8 million years. If they did cross, they would have certainly populated the whole of the Australasian continent as that too was all joined by land at various times since. And yet we so no evidence of any human like species in Australia until 60,000 ago or so.

I must remind that modern humans regularly swim across such stretches of open water. The Perth - Rottnest swim is run every year and has thousands of participants. (https://en.wikipedia.org/wiki/Rottnest_Channel_Swim#:~:text=The%20distance%20is%2019.7%20km,teams%20of%20two%20or%20four.) It is about the same distance as Bali - Lombok via Penida. And of course far greater distances have been crossed than that, such as the Channel between England and France.

Of course, absence of evidence is not evidence of absence but, it seems to me that if we are to remain true to scientific principles we must base our ideas on evidence and here, the evidence is that Homo sapiens is, if anything, more aquatic than Homo erectus.

Algis Kuliukas
Perth
April 2022



[i] Carlson, K., et al.: The pectoral girdle of StW 573 ("Little Foot") and its implications for shoulder evolution in the Hominina. cs 2021 JHE in press. https://doi.org/10.1016/j.jhevol.2021.102983

[ii] Christine M. Harper, Christopher B. Ruff, Adam D. Sylvester, Calcaneal shape variation in humans, nonhuman primates, and early hominins, Journal of Human Evolution, Volume 159, 2021, 103050,

ISSN 0047-2484, https://doi.org/10.1016/j.jhevol.2021.103050. (https://www.sciencedirect.com/science/article/pii/S0047248421001020)

[iii] DeSilva, J, McNutt, E, Benoit, J, Zipfel, B. One small step: A review of Plio-Pleistocene hominin foot evolution. Am J Phys Anthropol. 2019; 168:S67: 63– 140. https://doi.org/10.1002/ajpa.23750

[iv] Rightmire GP. Homo erectus and Middle Pleistocene hominins: brain size, skull form, and species recognition. J Hum Evol. 2013 Sep;65(3):223-52. doi: 10.1016/j.jhevol.2013.04.008. Epub 2013 Jul 10. PMID: 23850294.

[v] Antón, S. C.; Taboada, H. G.; et al. (2016). "Morphological variation in Homo erectus and the origins of developmental plasticity". Philosophical Transactions of the Royal Society B. 371 (1698): 20150236. doi:10.1098/rstb.2015.0236. PMC 4920293. PMID 27298467.

[vi] Alexandra Houssaye, P. Martin Sander, Nicole Klein, Adaptive Patterns in Aquatic Amniote Bone Microanatomy—More Complex than Previously Thought, Integrative and Comparative Biology, Volume 56, Issue 6, December 2016, Pages 1349–1369, https://doi.org/10.1093/icb/icw120


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Bernie,
  See link and pdf to an excellent paper from 2018, it evaluated the hip and leg function of homo, great apes, Hylobates and a few fossils.  Basically agrees with your thinking, our hips are crazy different.  A radical bipedal solution appears out of nowhere. 

Hip extensor mechanics and the evolution of walking and climbing capabilities in humans, apes, and fossil hominins


“Human bipedalism relies on a suite of hind limb adaptations, including a laterally oriented iliac blade and hip abductor complex, adducted hallux, and stiff midfoot (13), but few of these features have been linked empirically and in vivo to locomotor economy (i.e., the distance traveled per unit energy consumed). One derived feature tentatively tied to humans’ remarkable walking economy is a shorter and more dorsally projecting ischium, which permits hip extensor muscle torque production at full extension of the hip (180° hip angle between the trunk and leg) (491416) (Fig. 1). The resulting straight-legged gait…”


-Jack


On Apr 20, 2022, at 4:00 AM, Bernard Harper <bernieharper@...> wrote:



Hi Everyone,

    I was looking for a mention of the earliest appearance together of three features that seem to be consistently "human": Tiny canines, flattened face and a human-like pelvis. Yet nobody has spoken of them either individually or collectively. Once our gait and our gape massively diverge from the ape, we are not an ape. So a date and explanation for their earliest divergence seems vital for this discussion to have clarity IMO.

Bernie Harper

www.bernieharper.co.uk


 


--
Welcome to the Aquatic Ape Theory Discussion Group


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

fceska_gr
 

Hi Bernie,

 

The earliest human like teeth:

Graecopithecus, 7.2 Ma. These researchers believe El Greco may have been the first hominin.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0177127

 

and https://www.researchgate.net/publication/325452337_Response_to_Benoit_and_Thackeray_2017_'A_cladistic_analysis_of_Graecopithecus'

 

Post-cranial remains don’t exist for Graecopithecus, but researchers believe it was a bipedal swamp/wetland/savannah mosaic dweller (Read Madelaine Bohme’s book: Ancient Bones).

 

However, I believe El Greco was not the first hominin, but (close to) the LCA of chimps and humans. Being bipedal should not be taken as the defining trait of humanity. Probably most of the late Miocene – Pliocene bipeds were not more closely related to us.

 

See also:  

Possible hominin footprints from the late Miocene (c. 5.7 Ma) of Crete?

https://www.sciencedirect.com/science/article/pii/S001678781730113X

 

Best wishes,

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Bernard Harper
Sent: Wednesday, April 20, 2022 12:01 PM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Hi Everyone,

    I was looking for a mention of the earliest appearance together of three features that seem to be consistently "human": Tiny canines, flattened face and a human-like pelvis. Yet nobody has spoken of them either individually or collectively. Once our gait and our gape massively diverge from the ape, we are not an ape. So a date and explanation for their earliest divergence seems vital for this discussion to have clarity IMO.

Bernie Harper

www.bernieharper.co.uk


 


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

Marc Verhaegen
 

Hi Bernie,
- A very flat face (chin, less protruding midface & smaller nose <Hn, high forehead >Hn) = H.sapiens AFAIK = vertical wading-walking, +-not diving any more (post-aquatic).
- Rel.small, more incisor-like canines might be already early-hominoid. Australopiths had even smaller canines.
- Low pelvis (but more flaring in australopiths than in Homo) is probably early-hominoid: apes evolved in parallel higher ilia?

_______

Hi Everyone, I was looking for a mention of the earliest appearance together of 3 features that seem to be consistently "human": Tiny canines, flattened face and a human-like pelvis. Yet nobody has spoken of them either individually or collectively. Once our gait and our gape massively diverge from the ape, we are not an ape. So a date and explanation for their earliest divergence seems vital for this discussion to have clarity IMO.
Bernie Harper
www.bernieharper.co.uk


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

Gareth Morgan
 

Thanks, Berrie 

three features that seem to be consistently "human": Tiny canines, flattened face and a human-like pelvis.

Some might cite other " consistently human" features -- e.g. subcutaneaous fat, large brain, bipedalism, multi-pyramidal kidneys, prolific eccrine glands, menopause, adducted hallux, vernix, rotated pectoral muscles, loss of estrus, naked skin, etc etc, depending on their special interests....

As to "tiny canines, flattened face and a human-like pelvis", The first is the only one that could be distantly related to an aquatic liifestyle.*** The other two are directly related to bipedalism, which seems to have evolved long before any true aquatic adaptations,, so hardly relevant to a discussion on when we were most aquatic...


G.

From: AAT@groups.io <AAT@groups.io> on behalf of Bernard Harper <bernieharper@...>
Sent: Wednesday, April 20, 2022 12:00 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?
 

Hi Everyone,

    I was looking for a mention of the earliest appearance together of three features that seem to be consistently "human": Tiny canines, flattened face and a human-like pelvis. Yet nobody has spoken of them either individually or collectively. Once our gait and our gape massively diverge from the ape, we are not an ape. So a date and explanation for their earliest divergence seems vital for this discussion to have clarity IMO.

Bernie Harper

www.bernieharper.co.uk


 


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

Bernard Harper
 

Hi Everyone,

    I was looking for a mention of the earliest appearance together of three features that seem to be consistently "human": Tiny canines, flattened face and a human-like pelvis. Yet nobody has spoken of them either individually or collectively. Once our gait and our gape massively diverge from the ape, we are not an ape. So a date and explanation for their earliest divergence seems vital for this discussion to have clarity IMO.

Bernie Harper

www.bernieharper.co.uk


 


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

Gareth Morgan
 

The climate I refer to from Miocene onwards is all supported by scientific research.

Yes. It's only the older stuff I decline to offer any opinions on.


There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel  

I have no problem with that.



 Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

Smaller, maybe. How do you determine tree climbing skills? In any case Australopiths were less aquatic than us and apparently are not considered ancestral to us anyway. This is all also predicated on the view that bipedalism is an aquatic adaptation. I don't think that was why it evolved originally.


There is evidence that Pan’s feet were once like ours

I have been looking long and hard and found nothing. This is quite important. I won't take it on trust. All the evidence (in utero, for instance) that I can find says the opposite.



I think you misunderstood me… there was only one reversal

Great. If there have been no reversals, then in what possible sense can we be less aquatic than we used to be?


I’m talking about Pan (chimps) not Homo.

The premise I thought we were discussing was the one about whether early Homo was more or less aquatic than us. Whether chimps reverted or not really doesn't have any bearing.



Thick brow ridges are great if you dive, browse and forage underwater... to push water away from the eyes

This is simply not true. I've mentioned katabatic flow to you before. When any fluid flows over a ridge it drives forcibly down the other side. Into your eyes in other words if it is a brow ridge. Here's a diagram of a "Chinook wind" to illustrate what happens.



"A 40- to 50-mph wind over the ridges and passes may reach speeds of 80 to 100 mph by the time the air reaches the foothills (on the other side)".

It therefore follows that losing the brow ridge makes for better underwater vision. The more aquatic Asian people have less of a brow ridge than westerners and modern Man has a more "streamlined" face than any previous ancestor. i.e. more aquatic.



Neanderthals were more aquatic than Homo sapiens. 

A bigger brain, I happily concede. However all the known big headed humanoids became extinct -- proto-Innuit, Boskop man, "coneheads", Neanderthals.... The fact that fewer and fewer females appeared over time suggests that heads became too big to pass through the birth canal, killing the mothers in childbirth. We are about on the sustainable limit, partly thanks to Caesarian sections. A reality that anthropologists manage to ignore, preferring to focus on how jolly intelligent they think they are.

Homo erectus had a tiny brain anyway. Are we to conclude then that he was less aquatic than us? Makes sense. We just can't have it both ways.

Big, heavy bones are really a huge handicap in the water if you think about it. Bad for swimming and floating. Good, on the way down, for diving. Coming up...  good for drowning. Manageable in sea water. Big problem in fresh. Neanderthal was robust because, like Australopithecus robustus, he was designed to live mostly on land and struggled to make a living in the water, not yet having our perfect neutral buoyancy and other modern refinements. Frequently fractured his skull diving in, apparently.


As you know I consider the most aquatic hominin ever was Strandlooper (Boskop man) -- extinct for only a few hundred years or so. If you look at all the (aquatic) features that distinguish us from earlier ancestors, Strandlooper had them all, but very much more so. We know they were fully dependent on marine resources, because to find even a blade of grass they would have had to cross both the Kalahari and the Namib deserts, the latter having existed for over 50 million years, and you can see their shell middens from many miles away.. 

They were more gracile than us. "paper thin ribs" Their brains were a full 30% bigger than ours (forebrains + 50%). No brow ridge at all. Tiny teeth. Very prominent, sharp chin. Different in every way from the rugged Neanderthals. More aquatic....


 just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. 


Precisely, then we obviously have more aquatic adaptations than any previous hominin who hadn't yet developed them. i.e we are the most aquatic (surviving) hominin.

QED.

G.


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 7:02 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?
 

Thanks, Gareth

Thanks, Francesca.

 

Would it be possible to reveal the source of this text

 

That would be me.  Email, subject "Second draft" about where when and how we became aquatic.

Ok, thanks. I’ll have another look for it.

 

 many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

Agreed. But they didn't spring up, fully formed overnight. They gradually improved, gradually increased in number and range of functions.

Agreed, that’s what I’ve been writing about.

 

I'm not making any guesses about what happened before the Miocene --  what the climate was like in some particular region, tectonic events, sea levels, vegetation, predators or the particular 'cause' of any specific change in physiology. For one thing I'm sure that none of these conditions remained unchanged for millions of years at any point, so too much of it is guesswork based on insufficient evidence. Almost anything could have happened somewhere at some point.

The climate I refer to from Miocene onwards is all supported by scientific research.

 

reversal from upright bipedalism towards arborealism

 

Not aware of any evidence for this "reversal". Not to say it couldn't or didn't happen, but if I ever knew of any evidence, I've forgotten.

There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel, from an already upright common ancestor, after splitting from a common ancestor. First they walked on 4 legs, then they walked on 2, then they walked on their knuckles.

Many of the australopithecines seem to become more arboreal over time, not less. Eg. Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

 

My only comments would be that, once we learned to throw, we were never able to brachiate again because of the change in orientation of our pectoral muscle.. Once we became bipedal, the loss of the divergent hallux meant we could never grasp a branch with our feet again. Not sure what kind of arborealism this would leave us. 

Humans didn’t become arboreal again, only Pan did. The point I’m trying to make is that the LCA was probably already a biped. After we split, the Pan line remained bipedal (wading, wetland foraging) for a while, but later, they returned to the forests, started climbing trees and walking on their knuckles when on the ground. There is evidence that Pan’s feet were once like ours (adducted halluces) but later their big toe moved round to the side and they could grasp branches again. (Pan foetus in utero).

 

 I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

We need to look at the other features that you consider reversals to see if any of them are aquatic features that we have lost since early Homo....

I think you misunderstood me… there was only one reversal I mentioned and that was in chimps…

 

You mention...

 

6 Ma: human-like foot morphology (loss of arborealism). -- Arborealism is definitely not aquatic.

That’s my point. We lost arboreal features because we became more aquatic. Or, because we became more aquatic, we lost arboreal climbing abilities.

 

5-2 Ma: Gradual reversal from upright bipedalism. -- Don't think I believe this (Open to persuasion. See above.) but anyway bipedalism is either not essentially aquatic, in which case it's irrelevant or it is, in which case we have become more aquatic (more upright), not less, since early Homo.

Yes, again, I think you’ve misunderstood me. Here I’m talking about Pan (chimps) not Homo. Reverse adaptations in evolution are more common even than first time adaptations. It happens all the time. It’s a result of gene expression. Once the gene exists, it can be switched on or off, according to need. That’s why snakes evolved legs, then lost them again. So did whales, etc. Chimp and human ancestors lost their fur, then chimps grew theirs again, but we didn’t. Early elephants lost their fur but woolly mammoths grew it back as they moved north. Some people are sometimes born with a tail, or webbing between their toes, because those genes still exist, even if silenced at the moment.

 

I think Homo is closer to the LCA in morphology than chimps. We haven’t changed as much as they have over the past 5-6 million years, and this is seen in their Y-chromosome. And most of those changes in chimps probably happened in the last million years or so, after they diverged from bonobos. Bonobos are more like us than chimps are (see picture attached).

 

2.0 Ma: Homo appears:  taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism, more sophisticated stone tool use, shellfish consumption. -- Other than the thick brow ridges (survival benefit not obvious to me) these all seem to be increases in aquatic adaptation.

Thick brow ridges are great if you dive, browse and forage underwater. Like a hooded nose, they act together to push water away from the eyes and nostrils as you move forward.
And yes, this is meant to demonstrate increases in aquatic adaptation. My point is, early Homo at 2 Ma was far more aquatic morphologically than H. sapiens is now.

 

300 ka to present: Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?) -- Again these seem to be evidence of a more aquatic lifestyle, not less.

Yes, Neanderthals were more aquatic than Homo sapiens. Again, that’s my point.

 

Which aquatic features do you think we have lost, then? What makes you think we are less well adapted to warm, cold, shallow, deep, clean, muddy, fresh or salt water than any of the less derived hominins? Your entire timeline seems perfectly to support my observation that aquatic adaptations have been a gradual, punctuated, cumulative process that has continued till today.

We haven’t fully lost any of those earlier adaptations (that we know of) but each is less pronounced. We have smaller thoraxes and reduced lung capacity compared to early Homo, as we don’t dive as much. We have lighter bones because we walk/run more, swim and dive less. We can’t see well underwater unless this skill is practised from childhood. We have less pronounced brow ridges for the same reason. We have rounder crania as we spend more time standing upright, whereas the more elongated crania of early Homo is better supported in a swimming, floating or diving position. We can swim and dive pretty well, for an ape, but not as well as erectus probably did. They may have been able to swim vast distances and dive to much deeper levels. They could probably hold their breath much longer than we can, or close to what professional / record holding divers can do now.

 

As your mum once wrote, just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. We would only lose it if keeping it was detrimental to our survival. We haven’t regrown our fur because we discovered clothes and central heating as an alternative means of keeping warm (and still get to go to the beach!) If we hadn’t, only the most hairy of us would survive in a colder climate to pass on our genes, so over time, our children would get hairier and hairier. We didn’t revert to quadrupedalism because by the time we became fully terrestrial again, our legs were much longer in relation to our arms and so the proportions were all wrong. Plus, we didn’t need to. By then we were quite comfortable moving around on 2 legs and using our forelimbs for other purposes. It’s served us quite well.

 

F.

G.

 

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 12:19 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Hi Gareth,

 

Would it be possible to reveal the source of this text, please? I’d like to read it.

 

I agree that climate has influenced anthropoid evolution at many stages and in different ways, although I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

If we look at the evidence, many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

[1st aquatic stage: Hominoidea]

30-25 Ma Climate: very hot, humid, subtropical forests; tectonic upheaval and rifting causing vast areas of East Africa to become flooded, creating forested islands in vast East African lakes.

25-20 Ma: orthograde body plan and modifications towards bipedal posture, suspensory adaptations of the wrist, hand, shoulders and arms, larger, wider thorax, loss of tail, etc.
20 – 14 Ma: gradual increase in size from small-bodied primates to large chimp sized apes

Some time between 25 Ma and 16 Ma: partial loss of pelage (great apes relative to macaques)

Overall increase in eccrine gland distribution (between OWMs and apes)

Probable reduction in olfactory ability

PNS

c. 18- 16 Ma Hylobatidae diverge

 

16-14 Ma: Climate: temperature decrease, reduced humidity & loss of biodiversity in Africa; increasing biodiversity, humid sub-tropical forests & vast bodies of water in Eurasia, land bridges between the two continents. Disappearance of most apes from Africa. Appearance of many ape species in Eurasia.

15 Ma: loss of uricase mutation and the ability to store sugars as fat

 

[Hominidae]

15-13 Ma: the ability to fashion stone tools

c. 15-14 Ma: Pongo diverges

14 Ma: plantigrade locomotion (quadrupedal)

12-11 Ma: loss of prognathism, robust jaws, postural bipedalism (wading)

11-9 Ma: Vallesian crisis causes the extinction of many apes (loss of forests, loss of edible fruits, spreading grasslands, seasonal food availability).

10-7 Ma: bipedal hominids roam the river valleys & great lakes of southern Europe & the Tethys-Med coasts.
Smaller, more thickly enamelled dentition – change of diet.

 

[Homininae]

10-6 Ma: terrestrial bipedalism develops

c. 10-8 Ma: gorilla divergence

7 Ma: human-like P4 dental root morphology

6 Ma: human-like foot morphology (loss of arborealism)

 

6-5 Ma: Pan / Homo diverge

5.9 – 5.3 Ma: Mediterranean Salinity Crisis: great unidirectional migrations of fauna away from the southern Med, towards Africa.

5.3 Ma: Zanclean Megaflood cuts off land bridge between Eurasia and Africa.

Pliocene: 5.3 – 2.6 Ma. Sea-levels rise by up to 30 m. Hyper aridity in the Arabian Peninsula prevents migration of fauna eastwards.

During much of this period, the Arabian Peninsula is effectively cut off from the rest of the world.

 

4-3 Ma (PTERV1 virus throughout Africa, affects all African apes, but not Homo or Orangutans)

 

[Panini / Australopithecines]

Climate: Loss of forests and wetlands, increase of savannah and mosaic environments

5-2 Ma: Gradual reversal from upright bipedalism towards arborealism, and eventually, knucklewalking (also in Gorilla – homoplasy).

 

[Early Homo]

2.6 – 2.0 Ma: Pleistocene cooling, sea-level decrease, vast intercontinental shelves appear, land bridges, intertidal zones, migration routes

2.0 Ma: Homo appears: taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism
More sophisticated stone tool use, shellfish consumption.

 

[Later Homo]

2.6 Ma – 2.0 Ka: Pleistocene cooling, sea-level decrease, fluctuating temperatures (between glacials).

Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?)

 

[Homo sapiens]

300 Ka – present: Holocene (relatively stable climate, less overall humidity)

More gracile forms (taller, thinner – like waders), rounder crania, shorter femoral necks (adaptation for running). Loss of platycephaly, heavy brow-ridges, elongated crania. Brain capacity reduction, flatter faces, smaller teeth, smaller noses, lighter bones, smaller thoracic capacity,

Suggests H. sapiens was more terrestrial than earlier Homo.

 

Present – future? Anthropocene: Global warming, global climate fluctuations, sea-level rise, mass extinction events…where next?

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 18, 2022 10:57 AM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Homo sapiens is, if anything, more aquatic than Homo erectus.

 

 

"As far back as 17 March 1960, Professor Sir Alister Hardy noted in The New Scientist that modern humans have many features that suggest an aquatic phase in our evolution at some time in the distant past.  

The assumption was that a group of primates became isolated on an island or some other inaccessible waterside environment and survived by becoming adapted to a semi-aquatic lifestyle in the course of that single evolutionary event. Subsequent discoveries have provided data that both support and contradict that hypothesis. 

The present investigation proposes an alternative model whereby, over millions of years, a series of emergencies, in the shape of climate fluctuations, from fertile to desert conditions and coinciding with glacial and interglacial epochs, repeatedly imposed very stringent survival pressures on every group of hominids. From the late Miocene onward, scores of such events dictated the selection criteria for gradual adaptation to an opportunistic aquatic diet in a punctuated series of evolutionary steps. 

These adaptations were cumulative, and the fossil record includes progressively more numerous examples of each new version of pre-human and human with the passage of time, progressively larger deposits of bivalve shells and other edible aquatic food species in shell middens, and more widely distributed locations for the stone tools needed to process them efficiently. 

This interpretation of the available evidence satisfies all the significant objections to Hardy’s theory and leads to the conclusion that, physiologically, we are more aquatic now than we have ever been, and the astonishing current world records for breath holding and free diving would seem to support that view."

 

The idea of a single, brief isolation event producing all (or any) of our aquatic adaptations was never really credible.

G.   

 


From: AAT@groups.io <AAT@groups.io> on behalf of algiskuliukas <algis@...>
Sent: Monday, April 18, 2022 10:07 AM
To: AAT@groups.io <AAT@groups.io>
Subject: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

For those of us who are open minded enough to answer Hardy's question "Was Man More Aquatic in the Past?" with a cautious affirmative, a second question follows "If, so when was that and how much?"

Having thought about this for twenty-five years and studied human evolution (MSc from UCL with distinction and PhD in human bipedal origins from UWA) I have come to the conclusion that the answer to the second question should be "very early modern Homo sapiens ca 200,000 years ago or so"... and... "not much".

Some proponents (e.g. Marc Verhaegen and Stephen Munro) would argue that a better answer would be "Homo erectus (sensu stricto) - i.e. the Asian, rather than African forms" and "that they were predominantly bottom divers."

That's quite a difference.

So, I'd like to discuss this openly to see if I have missed something. 

Let me start the ball rolling...

Marc always cites pacheostosis (heavy bones) of H. erectus as leaving "no other possibility" than bottom diving for this hominin but were their bones really that heavy? If you look at the Nariokotome boy femur, for example, it is remarkably gracile. Where are the papers in the literature that backs up this claim?

Marc also cites their pelvic shape as being platypelloid, with long femoral necks as further evidence but, again, that's not what I see in the literature. Nariokotome boy's pelvis is remarkably narrow actually, android rather than platypelloid. In any case what his platypelloidy got to do with bottom diving? Dugongs/manatees do not share this convergence. Their pelves, appear to be on their way to becoming vestigial like cetacea.

Whether they had heavy bones or not, there is undeniable evidence of significant weight bearing in the bones of Homo erectus. The tibial plate, the oval shaped distal femoral condyles, the robust femoral head, the large acetabulae with superiorly orientated lunate surface. The robust sacral body and large lumbar vertebrae all speak of an upright, walking, terrestrial striding biped - just like us. They seem to have been predominantly striding bipeds, not divers.

Please don't misunderstand me. I am not suggesting that Homo erectus did not swim or dive - just that they didn't do so very much, and specifically, not as much as we modern human did, or still do.

When Homo erectus reached the islands of Java and Flores some 1.8 million years ago, they could have done so without getting their feet wet as the current archipelago of Indonesia has been connected via land bridges from time to time. Of course, I have no doubt they often went swimming and diving in coastal shallows but, if they were as adept as Marc suggests (a predominantly bottom diver, remember) then it is remarkable that the narrow strait of water between Bali and Lombok across the Wallace line, just 20km wide, was never crossed by these diving hominins in 1.8 million years. If they did cross, they would have certainly populated the whole of the Australasian continent as that too was all joined by land at various times since. And yet we so no evidence of any human like species in Australia until 60,000 ago or so.

I must remind that modern humans regularly swim across such stretches of open water. The Perth - Rottnest swim is run every year and has thousands of participants. (https://en.wikipedia.org/wiki/Rottnest_Channel_Swim#:~:text=The%20distance%20is%2019.7%20km,teams%20of%20two%20or%20four.) It is about the same distance as Bali - Lombok via Penida. And of course far greater distances have been crossed than that, such as the Channel between England and France.

Of course, absence of evidence is not evidence of absence but, it seems to me that if we are to remain true to scientific principles we must base our ideas on evidence and here, the evidence is that Homo sapiens is, if anything, more aquatic than Homo erectus.

Algis Kuliukas
Perth
April 2022


Hn in Iberia: ephemeral channels & their associated palustrine & lacustrine zones

Marc Verhaegen
 

Los Aljezares archaeological site (Alicante, Spain) and the MIS 6/5 open-air settlement in the Iberian Peninsula
Aleix Eixea cs 2022 doi org/10.1002/jqs.3424

The record of open-air mid-Palaeolithic sites in Iberia (Med.basin) is scarce, hampering the interpretation of the landscape use strategies developed by Hn in this area.
Here we present Los Aljezares, a new mid-Palaeolithic site found in Pleistocene fluvio-lacustrine deposits in the sedimentary basin of the Vinalopó River.
A U/Th age (132 ± 10 ka) from associated carbonate deposits allows us to attribute the site to the uppermost part of the mid- to late-Pleistocene (MIS 6/5).
To date, a total of 2 levels of human occupation have been identified, in which the density of lithic remains is low compared with cave & rock shelter sites in the region.
The first results of technology & use-wear, raw material procurement & geological data indicate a settlement in Los Aljezares along a territory characterised by ephemeral channels & their associated palustrine & lacustrine zones.
This palaeo-environment provided biotic & abiotic resources in a transit area between inland & coastal locations.


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

Gareth Morgan
 

Thank you A van A.

An interesting new finding for you here about pygmies -- https://www.nationalgeographic.com/culture/article/150728-african-pygmies-height-science-health-nutrition   They are born the same size as French babies and do have a growth spurt around puberty after all.


 the first origins of modern humans who I agree were the osteologically and dentally most marine adapted Hominids known.

This statement seems to be based on their having "relatively very large molars" ( Surely molars have been shrinking before and since. Clams are not tough)  and front teeth "adapted to eating tough marine vegetation. "  I have eaten many kinds of seaweed. None of them are tough. I would therefore like to know what other aquatic adaptations you think we have lost in the last couple of hundred thousand years that make us less aquatic than H. erectus.

Thanks.

G.



From: AAT@groups.io <AAT@groups.io> on behalf of alandarwinvanarsdale <alandarwinvanarsdale@...>
Sent: Tuesday, April 19, 2022 5:56 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?
 

Flores has been separated from Mainland Asia by deep water channels for at least 5 million years. There is no evidence Homo erectus ever reached Flores except one femur from Mata Menge of an individual who stood about 5 feet tall (LB1 stood about 3 feet tall). The Mata Menge Homo floresiensis fragments at about 700kya are about 20% smaller than LB1 (they were about 3 feet tall or less). ________________________________________________________________________________________________Since the Argue et al 2017 paper all evidence of humans on Flores has been attributed to Homo floresiensis by most authors. The reverse Island gigantism hypothesis for Homo “isolated: on Islands was poorly thought out from start to finish. Omnivores such as Homo are predicted by the Island Gigantism – dwarfism hypothesis to get larger, not smaller, just as the fossil record suggests when seen over time for humans on Islands. ________________________________________________________________________________________________I agree early modern humans were the osteologically most aquatically adapted Hominids known with the exception of the archaic human fragments from the Congo who did not live very long ago for archaic humans and show very high levels of aquatic adaptations. ___________________________________________________________________________________________________Grimaldi, the Qazfeh skulls and Sardinia 1 show high levels of marine adaptations. Very deep palates to push the tongue into the roof of the mouth during under water foraging. Relatively very high alveolar and mandibular prognathy. High domed heads well adapted to diving and triangular shaped nasal openings to more easily close the nose while diving by closing the nostrils and pushing the upper lip up onto the nostrils. __________________________________________________________________________________________________Juvenile teeth of Grimaldi show very unusual wear which can be from eating tough marine plants or holding fine line in between the teeth (such as for fishing). All early modern human fossils known, the Levant, Apidima 1, Sardinia 1 except Herto are within an easy walk of the ocean at the time they lived. ___________________________________________________________________________________________During very difficult environment times, as often was the case in the Middle Pleistocene when modern humans first appeared (Jebel Irhoud a “mosaic modern human” actually more closely related to neanderthals than extant humans was also within an easy walk of the Atlantic), aquatic environments would have supported a large percentage of the few humans alive when the continents were cold deserts for the most part. _______________________________________________________________________________________________Archaic pygmies appear to have inhabited arboreal and desert (xeric) environments in the Middle Pleistocene, and mixed with Homo heidelbergensis to give modern humans. The first great sea people known were archaic pygmies, as shown by their very wide Island distribution and presence on Madagascar. At Palaua archaic pygmies persisted until a few thousand years ago and were found in beach deposits (Berger et al, back then late archaic pygmies including Homo luzonensis were published as AMHs pygmies). So early modern humans inherited marine adapted traits from more marine branches of Middle Pleistocene archaic pygmies. The Narmada India archaic pygmies appear to have been arboreal (Middle Pleistocene continental archaic pygmies). ______________________________________________________________________________________________________The very high morphological diversity of archaic pygmies (as high or higher than all fossil Homo from Africa), and the deep divergence of the Andanamese Asiatic pygmy clade which extends into SE Asia, along with Andanamese having South Asian dental morphology, African cranial morphology, and no detected Denisovan genes unlike their close kin in Sahul and the Philippines, puts to rest the ROoA fantasy along with a large body of other evidence. One would need to go back about one million years for the last time more than half of Eurasian ancestry was in Africa, and more than half of Sub-Saharan ancestry today is Afro-Eurasian as evidenced both by the fossil record and genetics. Pygmies being monophyletic, as evidenced by many things including complex heart related genes, and reaching Africa from Asia not the other way around, puts ROoA to rest for once and for all for the well informed. ____________________________________________________________________________________________________Few would have predicted 25 years ago AAT would outlive ROoA! The strong archaic ghost elements in Africa are too old to support ROoA. They instead support Afro-Eurasian gene flow mostly replacing Original African populations in the last 5-230 thousand years with considerable continuity in Africa. With Eurasians being largely but not essentially replaced by gene flow from Africa at about 1 million years ago. Amended ROoA “essential replacement” is not in any way evidenced, not by fossils lithics or genes, no more so than complete replacement ROoA was. ___________________________________________________________________________________________________The fossil record does not support an East Asian origin of modern humans just as it does not support an East African origin. Herto shows continuity with East African archaics, and considerable gene flow to become modern human from Eurasia including the Sahulian aspect which is of SE European Homo heidelbergensis clade to Narmada to late Sundan Homo erectus origins. Because modern humans originated by a blending process, not the usually false linear evolution model, any place the fossil record is decent (such as Sunda China or East Africa), it is easy to fantasize that was the origin of modern humans. The fossil record strongly suggests, based upon fossil teeth, fully modern humans first began around or in SE Asia at about 120kya and spread to North Africa by gene flow at about 100kya and into Sub-Sahara quickly from North Africa. _________________________________________________________________________________________________As pointed out by Wolpoff, both AMHs and modern humans are fantasy taxa to begin with. They are chrono taxa. Nor does any trait define all extant human populations as AMHs except the greatly enlarged Broca area, irrespective of statements and publication by Stringer demonstrating considerable ignorance of archaic traits in extant human populations. Such as the plesiomorphic condition in pygmies, as seen in many of their populations today, being a lack of any ossified chin. Or Tasmanians (who are not much bigger than pygmies) having the archaic condition of front to back craniums. ___________________________________________________________________________________________________”AAT” for early modern humans can be seen as a sort of blending process which also involved minor bottle backing to give the first modern humans as beach dwelling hybrids of Homo heidelbergensis and archaic pygmies about 330kya some place(s) in the region of NW Africa, Asia Minor, SE Europe, South Asia over to Sunda and possibly the Philippines and even Sahul. Not China, Sub-Sahara, Europe outside of SE Europe, or the Continental interiors for the first origins of modern humans who I agree were the osteologically and dentally most marine adapted Hominids known. I interpret their relatively very large molars and anterior dentitions as being adapted to eating tough marine vegetation. In a similar fashion to the robust dentitions of paranthropines being adapted to eating tough terrestrial vegetation during periods of drought. With a trend since early modern humans of reduction in molar size and reduction of the relative size of the anterior to the posterior dentitions (Frayer 1978 for Europe, and other authors for Africa, Asia does not always follow this rule).

 

Sent from Mail for Windows

 

From: algiskuliukas
Sent: Monday, April 18, 2022 1:07 AM
To: AAT@groups.io
Subject: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

For those of us who are open minded enough to answer Hardy's question "Was Man More Aquatic in the Past?" with a cautious affirmative, a second question follows "If, so when was that and how much?"

Having thought about this for twenty-five years and studied human evolution (MSc from UCL with distinction and PhD in human bipedal origins from UWA) I have come to the conclusion that the answer to the second question should be "very early modern Homo sapiens ca 200,000 years ago or so"... and... "not much".

Some proponents (e.g. Marc Verhaegen and Stephen Munro) would argue that a better answer would be "Homo erectus (sensu stricto) - i.e. the Asian, rather than African forms" and "that they were predominantly bottom divers."

That's quite a difference.

So, I'd like to discuss this openly to see if I have missed something. 

Let me start the ball rolling...

Marc always cites pacheostosis (heavy bones) of H. erectus as leaving "no other possibility" than bottom diving for this hominin but were their bones really that heavy? If you look at the Nariokotome boy femur, for example, it is remarkably gracile. Where are the papers in the literature that backs up this claim?

Marc also cites their pelvic shape as being platypelloid, with long femoral necks as further evidence but, again, that's not what I see in the literature. Nariokotome boy's pelvis is remarkably narrow actually, android rather than platypelloid. In any case what his platypelloidy got to do with bottom diving? Dugongs/manatees do not share this convergence. Their pelves, appear to be on their way to becoming vestigial like cetacea.

Whether they had heavy bones or not, there is undeniable evidence of significant weight bearing in the bones of Homo erectus. The tibial plate, the oval shaped distal femoral condyles, the robust femoral head, the large acetabulae with superiorly orientated lunate surface. The robust sacral body and large lumbar vertebrae all speak of an upright, walking, terrestrial striding biped - just like us. They seem to have been predominantly striding bipeds, not divers.

Please don't misunderstand me. I am not suggesting that Homo erectus did not swim or dive - just that they didn't do so very much, and specifically, not as much as we modern human did, or still do.

When Homo erectus reached the islands of Java and Flores some 1.8 million years ago, they could have done so without getting their feet wet as the current archipelago of Indonesia has been connected via land bridges from time to time. Of course, I have no doubt they often went swimming and diving in coastal shallows but, if they were as adept as Marc suggests (a predominantly bottom diver, remember) then it is remarkable that the narrow strait of water between Bali and Lombok across the Wallace line, just 20km wide, was never crossed by these diving hominins in 1.8 million years. If they did cross, they would have certainly populated the whole of the Australasian continent as that too was all joined by land at various times since. And yet we so no evidence of any human like species in Australia until 60,000 ago or so.

I must remind that modern humans regularly swim across such stretches of open water. The Perth - Rottnest swim is run every year and has thousands of participants. (https://en.wikipedia.org/wiki/Rottnest_Channel_Swim#:~:text=The%20distance%20is%2019.7%20km,teams%20of%20two%20or%20four.) It is about the same distance as Bali - Lombok via Penida. And of course far greater distances have been crossed than that, such as the Channel between England and France.

Of course, absence of evidence is not evidence of absence but, it seems to me that if we are to remain true to scientific principles we must base our ideas on evidence and here, the evidence is that Homo sapiens is, if anything, more aquatic than Homo erectus.

Algis Kuliukas
Perth
April 2022

 


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

fceska_gr
 

Thanks, Gareth

Thanks, Francesca.

 

Would it be possible to reveal the source of this text

 

That would be me.  Email, subject "Second draft" about where when and how we became aquatic.

Ok, thanks. I’ll have another look for it.

 

 many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

Agreed. But they didn't spring up, fully formed overnight. They gradually improved, gradually increased in number and range of functions.

Agreed, that’s what I’ve been writing about.

 

I'm not making any guesses about what happened before the Miocene --  what the climate was like in some particular region, tectonic events, sea levels, vegetation, predators or the particular 'cause' of any specific change in physiology. For one thing I'm sure that none of these conditions remained unchanged for millions of years at any point, so too much of it is guesswork based on insufficient evidence. Almost anything could have happened somewhere at some point.

The climate I refer to from Miocene onwards is all supported by scientific research.

 

reversal from upright bipedalism towards arborealism

 

Not aware of any evidence for this "reversal". Not to say it couldn't or didn't happen, but if I ever knew of any evidence, I've forgotten.

There are quite a few scientists who now support that knuckle-walking developed in Pan and Gorilla in parallel, from an already upright common ancestor, after splitting from a common ancestor. First they walked on 4 legs, then they walked on 2, then they walked on their knuckles.

Many of the australopithecines seem to become more arboreal over time, not less. Eg. Australopithecus sediba, a very late surviving hominin, was clearly smaller and more arboreal than Lucy was 3.4 Ma.

 

My only comments would be that, once we learned to throw, we were never able to brachiate again because of the change in orientation of our pectoral muscle.. Once we became bipedal, the loss of the divergent hallux meant we could never grasp a branch with our feet again. Not sure what kind of arborealism this would leave us. 

Humans didn’t become arboreal again, only Pan did. The point I’m trying to make is that the LCA was probably already a biped. After we split, the Pan line remained bipedal (wading, wetland foraging) for a while, but later, they returned to the forests, started climbing trees and walking on their knuckles when on the ground. There is evidence that Pan’s feet were once like ours (adducted halluces) but later their big toe moved round to the side and they could grasp branches again. (Pan foetus in utero).

 

 I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

We need to look at the other features that you consider reversals to see if any of them are aquatic features that we have lost since early Homo....

I think you misunderstood me… there was only one reversal I mentioned and that was in chimps…

 

You mention...

 

6 Ma: human-like foot morphology (loss of arborealism). -- Arborealism is definitely not aquatic.

That’s my point. We lost arboreal features because we became more aquatic. Or, because we became more aquatic, we lost arboreal climbing abilities.

 

5-2 Ma: Gradual reversal from upright bipedalism. -- Don't think I believe this (Open to persuasion. See above.) but anyway bipedalism is either not essentially aquatic, in which case it's irrelevant or it is, in which case we have become more aquatic (more upright), not less, since early Homo.

Yes, again, I think you’ve misunderstood me. Here I’m talking about Pan (chimps) not Homo. Reverse adaptations in evolution are more common even than first time adaptations. It happens all the time. It’s a result of gene expression. Once the gene exists, it can be switched on or off, according to need. That’s why snakes evolved legs, then lost them again. So did whales, etc. Chimp and human ancestors lost their fur, then chimps grew theirs again, but we didn’t. Early elephants lost their fur but woolly mammoths grew it back as they moved north. Some people are sometimes born with a tail, or webbing between their toes, because those genes still exist, even if silenced at the moment.

 

I think Homo is closer to the LCA in morphology than chimps. We haven’t changed as much as they have over the past 5-6 million years, and this is seen in their Y-chromosome. And most of those changes in chimps probably happened in the last million years or so, after they diverged from bonobos. Bonobos are more like us than chimps are (see picture attached).

 

2.0 Ma: Homo appears:  taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism, more sophisticated stone tool use, shellfish consumption. -- Other than the thick brow ridges (survival benefit not obvious to me) these all seem to be increases in aquatic adaptation.

Thick brow ridges are great if you dive, browse and forage underwater. Like a hooded nose, they act together to push water away from the eyes and nostrils as you move forward.
And yes, this is meant to demonstrate increases in aquatic adaptation. My point is, early Homo at 2 Ma was far more aquatic morphologically than H. sapiens is now.

 

300 ka to present: Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?) -- Again these seem to be evidence of a more aquatic lifestyle, not less.

Yes, Neanderthals were more aquatic than Homo sapiens. Again, that’s my point.

 

Which aquatic features do you think we have lost, then? What makes you think we are less well adapted to warm, cold, shallow, deep, clean, muddy, fresh or salt water than any of the less derived hominins? Your entire timeline seems perfectly to support my observation that aquatic adaptations have been a gradual, punctuated, cumulative process that has continued till today.

We haven’t fully lost any of those earlier adaptations (that we know of) but each is less pronounced. We have smaller thoraxes and reduced lung capacity compared to early Homo, as we don’t dive as much. We have lighter bones because we walk/run more, swim and dive less. We can’t see well underwater unless this skill is practised from childhood. We have less pronounced brow ridges for the same reason. We have rounder crania as we spend more time standing upright, whereas the more elongated crania of early Homo is better supported in a swimming, floating or diving position. We can swim and dive pretty well, for an ape, but not as well as erectus probably did. They may have been able to swim vast distances and dive to much deeper levels. They could probably hold their breath much longer than we can, or close to what professional / record holding divers can do now.

 

As your mum once wrote, just because we evolved a certain feature, it doesn’t mean we will lose it once we stop needing it. We would only lose it if keeping it was detrimental to our survival. We haven’t regrown our fur because we discovered clothes and central heating as an alternative means of keeping warm (and still get to go to the beach!) If we hadn’t, only the most hairy of us would survive in a colder climate to pass on our genes, so over time, our children would get hairier and hairier. We didn’t revert to quadrupedalism because by the time we became fully terrestrial again, our legs were much longer in relation to our arms and so the proportions were all wrong. Plus, we didn’t need to. By then we were quite comfortable moving around on 2 legs and using our forelimbs for other purposes. It’s served us quite well.

 

F.

G.

 

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 12:19 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Hi Gareth,

 

Would it be possible to reveal the source of this text, please? I’d like to read it.

 

I agree that climate has influenced anthropoid evolution at many stages and in different ways, although I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

If we look at the evidence, many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

[1st aquatic stage: Hominoidea]

30-25 Ma Climate: very hot, humid, subtropical forests; tectonic upheaval and rifting causing vast areas of East Africa to become flooded, creating forested islands in vast East African lakes.

25-20 Ma: orthograde body plan and modifications towards bipedal posture, suspensory adaptations of the wrist, hand, shoulders and arms, larger, wider thorax, loss of tail, etc.
20 – 14 Ma: gradual increase in size from small-bodied primates to large chimp sized apes

Some time between 25 Ma and 16 Ma: partial loss of pelage (great apes relative to macaques)

Overall increase in eccrine gland distribution (between OWMs and apes)

Probable reduction in olfactory ability

PNS

c. 18- 16 Ma Hylobatidae diverge

 

16-14 Ma: Climate: temperature decrease, reduced humidity & loss of biodiversity in Africa; increasing biodiversity, humid sub-tropical forests & vast bodies of water in Eurasia, land bridges between the two continents. Disappearance of most apes from Africa. Appearance of many ape species in Eurasia.

15 Ma: loss of uricase mutation and the ability to store sugars as fat

 

[Hominidae]

15-13 Ma: the ability to fashion stone tools

c. 15-14 Ma: Pongo diverges

14 Ma: plantigrade locomotion (quadrupedal)

12-11 Ma: loss of prognathism, robust jaws, postural bipedalism (wading)

11-9 Ma: Vallesian crisis causes the extinction of many apes (loss of forests, loss of edible fruits, spreading grasslands, seasonal food availability).

10-7 Ma: bipedal hominids roam the river valleys & great lakes of southern Europe & the Tethys-Med coasts.
Smaller, more thickly enamelled dentition – change of diet.

 

[Homininae]

10-6 Ma: terrestrial bipedalism develops

c. 10-8 Ma: gorilla divergence

7 Ma: human-like P4 dental root morphology

6 Ma: human-like foot morphology (loss of arborealism)

 

6-5 Ma: Pan / Homo diverge

5.9 – 5.3 Ma: Mediterranean Salinity Crisis: great unidirectional migrations of fauna away from the southern Med, towards Africa.

5.3 Ma: Zanclean Megaflood cuts off land bridge between Eurasia and Africa.

Pliocene: 5.3 – 2.6 Ma. Sea-levels rise by up to 30 m. Hyper aridity in the Arabian Peninsula prevents migration of fauna eastwards.

During much of this period, the Arabian Peninsula is effectively cut off from the rest of the world.

 

4-3 Ma (PTERV1 virus throughout Africa, affects all African apes, but not Homo or Orangutans)

 

[Panini / Australopithecines]

Climate: Loss of forests and wetlands, increase of savannah and mosaic environments

5-2 Ma: Gradual reversal from upright bipedalism towards arborealism, and eventually, knucklewalking (also in Gorilla – homoplasy).

 

[Early Homo]

2.6 – 2.0 Ma: Pleistocene cooling, sea-level decrease, vast intercontinental shelves appear, land bridges, intertidal zones, migration routes

2.0 Ma: Homo appears: taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism
More sophisticated stone tool use, shellfish consumption.

 

[Later Homo]

2.6 Ma – 2.0 Ka: Pleistocene cooling, sea-level decrease, fluctuating temperatures (between glacials).

Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?)

 

[Homo sapiens]

300 Ka – present: Holocene (relatively stable climate, less overall humidity)

More gracile forms (taller, thinner – like waders), rounder crania, shorter femoral necks (adaptation for running). Loss of platycephaly, heavy brow-ridges, elongated crania. Brain capacity reduction, flatter faces, smaller teeth, smaller noses, lighter bones, smaller thoracic capacity,

Suggests H. sapiens was more terrestrial than earlier Homo.

 

Present – future? Anthropocene: Global warming, global climate fluctuations, sea-level rise, mass extinction events…where next?

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 18, 2022 10:57 AM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Homo sapiens is, if anything, more aquatic than Homo erectus.

 

 

"As far back as 17 March 1960, Professor Sir Alister Hardy noted in The New Scientist that modern humans have many features that suggest an aquatic phase in our evolution at some time in the distant past.  

The assumption was that a group of primates became isolated on an island or some other inaccessible waterside environment and survived by becoming adapted to a semi-aquatic lifestyle in the course of that single evolutionary event. Subsequent discoveries have provided data that both support and contradict that hypothesis. 

The present investigation proposes an alternative model whereby, over millions of years, a series of emergencies, in the shape of climate fluctuations, from fertile to desert conditions and coinciding with glacial and interglacial epochs, repeatedly imposed very stringent survival pressures on every group of hominids. From the late Miocene onward, scores of such events dictated the selection criteria for gradual adaptation to an opportunistic aquatic diet in a punctuated series of evolutionary steps. 

These adaptations were cumulative, and the fossil record includes progressively more numerous examples of each new version of pre-human and human with the passage of time, progressively larger deposits of bivalve shells and other edible aquatic food species in shell middens, and more widely distributed locations for the stone tools needed to process them efficiently. 

This interpretation of the available evidence satisfies all the significant objections to Hardy’s theory and leads to the conclusion that, physiologically, we are more aquatic now than we have ever been, and the astonishing current world records for breath holding and free diving would seem to support that view."

 

The idea of a single, brief isolation event producing all (or any) of our aquatic adaptations was never really credible.

G.   

 


From: AAT@groups.io <AAT@groups.io> on behalf of algiskuliukas <algis@...>
Sent: Monday, April 18, 2022 10:07 AM
To: AAT@groups.io <AAT@groups.io>
Subject: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

For those of us who are open minded enough to answer Hardy's question "Was Man More Aquatic in the Past?" with a cautious affirmative, a second question follows "If, so when was that and how much?"

Having thought about this for twenty-five years and studied human evolution (MSc from UCL with distinction and PhD in human bipedal origins from UWA) I have come to the conclusion that the answer to the second question should be "very early modern Homo sapiens ca 200,000 years ago or so"... and... "not much".

Some proponents (e.g. Marc Verhaegen and Stephen Munro) would argue that a better answer would be "Homo erectus (sensu stricto) - i.e. the Asian, rather than African forms" and "that they were predominantly bottom divers."

That's quite a difference.

So, I'd like to discuss this openly to see if I have missed something. 

Let me start the ball rolling...

Marc always cites pacheostosis (heavy bones) of H. erectus as leaving "no other possibility" than bottom diving for this hominin but were their bones really that heavy? If you look at the Nariokotome boy femur, for example, it is remarkably gracile. Where are the papers in the literature that backs up this claim?

Marc also cites their pelvic shape as being platypelloid, with long femoral necks as further evidence but, again, that's not what I see in the literature. Nariokotome boy's pelvis is remarkably narrow actually, android rather than platypelloid. In any case what his platypelloidy got to do with bottom diving? Dugongs/manatees do not share this convergence. Their pelves, appear to be on their way to becoming vestigial like cetacea.

Whether they had heavy bones or not, there is undeniable evidence of significant weight bearing in the bones of Homo erectus. The tibial plate, the oval shaped distal femoral condyles, the robust femoral head, the large acetabulae with superiorly orientated lunate surface. The robust sacral body and large lumbar vertebrae all speak of an upright, walking, terrestrial striding biped - just like us. They seem to have been predominantly striding bipeds, not divers.

Please don't misunderstand me. I am not suggesting that Homo erectus did not swim or dive - just that they didn't do so very much, and specifically, not as much as we modern human did, or still do.

When Homo erectus reached the islands of Java and Flores some 1.8 million years ago, they could have done so without getting their feet wet as the current archipelago of Indonesia has been connected via land bridges from time to time. Of course, I have no doubt they often went swimming and diving in coastal shallows but, if they were as adept as Marc suggests (a predominantly bottom diver, remember) then it is remarkable that the narrow strait of water between Bali and Lombok across the Wallace line, just 20km wide, was never crossed by these diving hominins in 1.8 million years. If they did cross, they would have certainly populated the whole of the Australasian continent as that too was all joined by land at various times since. And yet we so no evidence of any human like species in Australia until 60,000 ago or so.

I must remind that modern humans regularly swim across such stretches of open water. The Perth - Rottnest swim is run every year and has thousands of participants. (https://en.wikipedia.org/wiki/Rottnest_Channel_Swim#:~:text=The%20distance%20is%2019.7%20km,teams%20of%20two%20or%20four.) It is about the same distance as Bali - Lombok via Penida. And of course far greater distances have been crossed than that, such as the Channel between England and France.

Of course, absence of evidence is not evidence of absence but, it seems to me that if we are to remain true to scientific principles we must base our ideas on evidence and here, the evidence is that Homo sapiens is, if anything, more aquatic than Homo erectus.

Algis Kuliukas
Perth
April 2022


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

alandarwinvanarsdale
 

Flores has been separated from Mainland Asia by deep water channels for at least 5 million years. There is no evidence Homo erectus ever reached Flores except one femur from Mata Menge of an individual who stood about 5 feet tall (LB1 stood about 3 feet tall). The Mata Menge Homo floresiensis fragments at about 700kya are about 20% smaller than LB1 (they were about 3 feet tall or less). ________________________________________________________________________________________________Since the Argue et al 2017 paper all evidence of humans on Flores has been attributed to Homo floresiensis by most authors. The reverse Island gigantism hypothesis for Homo “isolated: on Islands was poorly thought out from start to finish. Omnivores such as Homo are predicted by the Island Gigantism – dwarfism hypothesis to get larger, not smaller, just as the fossil record suggests when seen over time for humans on Islands. ________________________________________________________________________________________________I agree early modern humans were the osteologically most aquatically adapted Hominids known with the exception of the archaic human fragments from the Congo who did not live very long ago for archaic humans and show very high levels of aquatic adaptations. ___________________________________________________________________________________________________Grimaldi, the Qazfeh skulls and Sardinia 1 show high levels of marine adaptations. Very deep palates to push the tongue into the roof of the mouth during under water foraging. Relatively very high alveolar and mandibular prognathy. High domed heads well adapted to diving and triangular shaped nasal openings to more easily close the nose while diving by closing the nostrils and pushing the upper lip up onto the nostrils. __________________________________________________________________________________________________Juvenile teeth of Grimaldi show very unusual wear which can be from eating tough marine plants or holding fine line in between the teeth (such as for fishing). All early modern human fossils known, the Levant, Apidima 1, Sardinia 1 except Herto are within an easy walk of the ocean at the time they lived. ___________________________________________________________________________________________During very difficult environment times, as often was the case in the Middle Pleistocene when modern humans first appeared (Jebel Irhoud a “mosaic modern human” actually more closely related to neanderthals than extant humans was also within an easy walk of the Atlantic), aquatic environments would have supported a large percentage of the few humans alive when the continents were cold deserts for the most part. _______________________________________________________________________________________________Archaic pygmies appear to have inhabited arboreal and desert (xeric) environments in the Middle Pleistocene, and mixed with Homo heidelbergensis to give modern humans. The first great sea people known were archaic pygmies, as shown by their very wide Island distribution and presence on Madagascar. At Palaua archaic pygmies persisted until a few thousand years ago and were found in beach deposits (Berger et al, back then late archaic pygmies including Homo luzonensis were published as AMHs pygmies). So early modern humans inherited marine adapted traits from more marine branches of Middle Pleistocene archaic pygmies. The Narmada India archaic pygmies appear to have been arboreal (Middle Pleistocene continental archaic pygmies). ______________________________________________________________________________________________________The very high morphological diversity of archaic pygmies (as high or higher than all fossil Homo from Africa), and the deep divergence of the Andanamese Asiatic pygmy clade which extends into SE Asia, along with Andanamese having South Asian dental morphology, African cranial morphology, and no detected Denisovan genes unlike their close kin in Sahul and the Philippines, puts to rest the ROoA fantasy along with a large body of other evidence. One would need to go back about one million years for the last time more than half of Eurasian ancestry was in Africa, and more than half of Sub-Saharan ancestry today is Afro-Eurasian as evidenced both by the fossil record and genetics. Pygmies being monophyletic, as evidenced by many things including complex heart related genes, and reaching Africa from Asia not the other way around, puts ROoA to rest for once and for all for the well informed. ____________________________________________________________________________________________________Few would have predicted 25 years ago AAT would outlive ROoA! The strong archaic ghost elements in Africa are too old to support ROoA. They instead support Afro-Eurasian gene flow mostly replacing Original African populations in the last 5-230 thousand years with considerable continuity in Africa. With Eurasians being largely but not essentially replaced by gene flow from Africa at about 1 million years ago. Amended ROoA “essential replacement” is not in any way evidenced, not by fossils lithics or genes, no more so than complete replacement ROoA was. ___________________________________________________________________________________________________The fossil record does not support an East Asian origin of modern humans just as it does not support an East African origin. Herto shows continuity with East African archaics, and considerable gene flow to become modern human from Eurasia including the Sahulian aspect which is of SE European Homo heidelbergensis clade to Narmada to late Sundan Homo erectus origins. Because modern humans originated by a blending process, not the usually false linear evolution model, any place the fossil record is decent (such as Sunda China or East Africa), it is easy to fantasize that was the origin of modern humans. The fossil record strongly suggests, based upon fossil teeth, fully modern humans first began around or in SE Asia at about 120kya and spread to North Africa by gene flow at about 100kya and into Sub-Sahara quickly from North Africa. _________________________________________________________________________________________________As pointed out by Wolpoff, both AMHs and modern humans are fantasy taxa to begin with. They are chrono taxa. Nor does any trait define all extant human populations as AMHs except the greatly enlarged Broca area, irrespective of statements and publication by Stringer demonstrating considerable ignorance of archaic traits in extant human populations. Such as the plesiomorphic condition in pygmies, as seen in many of their populations today, being a lack of any ossified chin. Or Tasmanians (who are not much bigger than pygmies) having the archaic condition of front to back craniums. ___________________________________________________________________________________________________”AAT” for early modern humans can be seen as a sort of blending process which also involved minor bottle backing to give the first modern humans as beach dwelling hybrids of Homo heidelbergensis and archaic pygmies about 330kya some place(s) in the region of NW Africa, Asia Minor, SE Europe, South Asia over to Sunda and possibly the Philippines and even Sahul. Not China, Sub-Sahara, Europe outside of SE Europe, or the Continental interiors for the first origins of modern humans who I agree were the osteologically and dentally most marine adapted Hominids known. I interpret their relatively very large molars and anterior dentitions as being adapted to eating tough marine vegetation. In a similar fashion to the robust dentitions of paranthropines being adapted to eating tough terrestrial vegetation during periods of drought. With a trend since early modern humans of reduction in molar size and reduction of the relative size of the anterior to the posterior dentitions (Frayer 1978 for Europe, and other authors for Africa, Asia does not always follow this rule).

 

Sent from Mail for Windows

 

From: algiskuliukas
Sent: Monday, April 18, 2022 1:07 AM
To: AAT@groups.io
Subject: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

For those of us who are open minded enough to answer Hardy's question "Was Man More Aquatic in the Past?" with a cautious affirmative, a second question follows "If, so when was that and how much?"

Having thought about this for twenty-five years and studied human evolution (MSc from UCL with distinction and PhD in human bipedal origins from UWA) I have come to the conclusion that the answer to the second question should be "very early modern Homo sapiens ca 200,000 years ago or so"... and... "not much".

Some proponents (e.g. Marc Verhaegen and Stephen Munro) would argue that a better answer would be "Homo erectus (sensu stricto) - i.e. the Asian, rather than African forms" and "that they were predominantly bottom divers."

That's quite a difference.

So, I'd like to discuss this openly to see if I have missed something. 

Let me start the ball rolling...

Marc always cites pacheostosis (heavy bones) of H. erectus as leaving "no other possibility" than bottom diving for this hominin but were their bones really that heavy? If you look at the Nariokotome boy femur, for example, it is remarkably gracile. Where are the papers in the literature that backs up this claim?

Marc also cites their pelvic shape as being platypelloid, with long femoral necks as further evidence but, again, that's not what I see in the literature. Nariokotome boy's pelvis is remarkably narrow actually, android rather than platypelloid. In any case what his platypelloidy got to do with bottom diving? Dugongs/manatees do not share this convergence. Their pelves, appear to be on their way to becoming vestigial like cetacea.

Whether they had heavy bones or not, there is undeniable evidence of significant weight bearing in the bones of Homo erectus. The tibial plate, the oval shaped distal femoral condyles, the robust femoral head, the large acetabulae with superiorly orientated lunate surface. The robust sacral body and large lumbar vertebrae all speak of an upright, walking, terrestrial striding biped - just like us. They seem to have been predominantly striding bipeds, not divers.

Please don't misunderstand me. I am not suggesting that Homo erectus did not swim or dive - just that they didn't do so very much, and specifically, not as much as we modern human did, or still do.

When Homo erectus reached the islands of Java and Flores some 1.8 million years ago, they could have done so without getting their feet wet as the current archipelago of Indonesia has been connected via land bridges from time to time. Of course, I have no doubt they often went swimming and diving in coastal shallows but, if they were as adept as Marc suggests (a predominantly bottom diver, remember) then it is remarkable that the narrow strait of water between Bali and Lombok across the Wallace line, just 20km wide, was never crossed by these diving hominins in 1.8 million years. If they did cross, they would have certainly populated the whole of the Australasian continent as that too was all joined by land at various times since. And yet we so no evidence of any human like species in Australia until 60,000 ago or so.

I must remind that modern humans regularly swim across such stretches of open water. The Perth - Rottnest swim is run every year and has thousands of participants. (https://en.wikipedia.org/wiki/Rottnest_Channel_Swim#:~:text=The%20distance%20is%2019.7%20km,teams%20of%20two%20or%20four.) It is about the same distance as Bali - Lombok via Penida. And of course far greater distances have been crossed than that, such as the Channel between England and France.

Of course, absence of evidence is not evidence of absence but, it seems to me that if we are to remain true to scientific principles we must base our ideas on evidence and here, the evidence is that Homo sapiens is, if anything, more aquatic than Homo erectus.

Algis Kuliukas
Perth
April 2022

 


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

Gareth Morgan
 

Thanks, Francesca.


Would it be possible to reveal the source of this text

That would be me.  Email, subject "Second draft" about where when and how we became aquatic.


 many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

Agreed. But they didn't spring up, fully formed overnight. They gradually improved, gradually increased in number and range of functions.



I'm not making any guesses about what happened before the Miocene --  what the climate was like in some particular region, tectonic events, sea levels, vegetation, predators or the particular 'cause' of any specific change in physiology. For one thing I'm sure that none of these conditions remained unchanged for millions of years at any point, so too much of it is guesswork based on insufficient evidence. Almost anything could have happened somewhere at some point.


reversal from upright bipedalism towards arborealism

Not aware of any evidence for this "reversal". Not to say it couldn't or didn't happen, but if I ever knew of any evidence, I've forgotten.

My only comments would be that, once we learned to throw, we were never able to brachiate again because of the change in orientation of our pectoral muscle.. Once we became bipedal, the loss of the divergent hallux meant we could never grasp a branch with our feet again. Not sure what kind of arborealism this would leave us. 



 I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

We need to look at the other features that you consider reversals to see if any of them are aquatic features that we have lost since early Homo....


You mention...

6 Ma: human-like foot morphology (loss of arborealism). -- Arborealism is definitely not aquatic.

5-2 Ma: Gradual reversal from upright bipedalism. -- Don't think I believe this (Open to persuasion. See above.) but anyway bipedalism is either not essentially aquatic, in which case it's irrelevant or it is, in which case we have become more aquatic (more upright), not less, since early Homo.

2.0 Ma: Homo appears:  taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism, more sophisticated stone tool use, shellfish consumption. -- Other than the thick brow ridges (survival benefit not obvious to me) these all seem to be increases in aquatic adaptation.

300 ka to present: Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?) -- Again these seem to be evidence of a more aquatic lifestyle, not less.


Which aquatic features do you think we have lost, then? What makes you think we are less well adapted to warm, cold, shallow, deep, clean, muddy, fresh or salt water than any of the less derived hominins? Your entire timeline seems perfectly to support my observation that aquatic adaptations have been a gradual, punctuated, cumulative process that has continued till today.


G.

 






From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Tuesday, April 19, 2022 12:19 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?
 

Hi Gareth,

 

Would it be possible to reveal the source of this text, please? I’d like to read it.

 

I agree that climate has influenced anthropoid evolution at many stages and in different ways, although I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

If we look at the evidence, many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

[1st aquatic stage: Hominoidea]

30-25 Ma Climate: very hot, humid, subtropical forests; tectonic upheaval and rifting causing vast areas of East Africa to become flooded, creating forested islands in vast East African lakes.

25-20 Ma: orthograde body plan and modifications towards bipedal posture, suspensory adaptations of the wrist, hand, shoulders and arms, larger, wider thorax, loss of tail, etc.
20 – 14 Ma: gradual increase in size from small-bodied primates to large chimp sized apes

Some time between 25 Ma and 16 Ma: partial loss of pelage (great apes relative to macaques)

Overall increase in eccrine gland distribution (between OWMs and apes)

Probable reduction in olfactory ability

PNS

c. 18- 16 Ma Hylobatidae diverge

 

16-14 Ma: Climate: temperature decrease, reduced humidity & loss of biodiversity in Africa; increasing biodiversity, humid sub-tropical forests & vast bodies of water in Eurasia, land bridges between the two continents. Disappearance of most apes from Africa. Appearance of many ape species in Eurasia.

15 Ma: loss of uricase mutation and the ability to store sugars as fat

 

[Hominidae]

15-13 Ma: the ability to fashion stone tools

c. 15-14 Ma: Pongo diverges

14 Ma: plantigrade locomotion (quadrupedal)

12-11 Ma: loss of prognathism, robust jaws, postural bipedalism (wading)

11-9 Ma: Vallesian crisis causes the extinction of many apes (loss of forests, loss of edible fruits, spreading grasslands, seasonal food availability).

10-7 Ma: bipedal hominids roam the river valleys & great lakes of southern Europe & the Tethys-Med coasts.
Smaller, more thickly enamelled dentition – change of diet.

 

[Homininae]

10-6 Ma: terrestrial bipedalism develops

c. 10-8 Ma: gorilla divergence

7 Ma: human-like P4 dental root morphology

6 Ma: human-like foot morphology (loss of arborealism)

 

6-5 Ma: Pan / Homo diverge

5.9 – 5.3 Ma: Mediterranean Salinity Crisis: great unidirectional migrations of fauna away from the southern Med, towards Africa.

5.3 Ma: Zanclean Megaflood cuts off land bridge between Eurasia and Africa.

Pliocene: 5.3 – 2.6 Ma. Sea-levels rise by up to 30 m. Hyper aridity in the Arabian Peninsula prevents migration of fauna eastwards.

During much of this period, the Arabian Peninsula is effectively cut off from the rest of the world.

 

4-3 Ma (PTERV1 virus throughout Africa, affects all African apes, but not Homo or Orangutans)

 

[Panini / Australopithecines]

Climate: Loss of forests and wetlands, increase of savannah and mosaic environments

5-2 Ma: Gradual reversal from upright bipedalism towards arborealism, and eventually, knucklewalking (also in Gorilla – homoplasy).

 

[Early Homo]

2.6 – 2.0 Ma: Pleistocene cooling, sea-level decrease, vast intercontinental shelves appear, land bridges, intertidal zones, migration routes

2.0 Ma: Homo appears: taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism
More sophisticated stone tool use, shellfish consumption.

 

[Later Homo]

2.6 Ma – 2.0 Ka: Pleistocene cooling, sea-level decrease, fluctuating temperatures (between glacials).

Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?)

 

[Homo sapiens]

300 Ka – present: Holocene (relatively stable climate, less overall humidity)

More gracile forms (taller, thinner – like waders), rounder crania, shorter femoral necks (adaptation for running). Loss of platycephaly, heavy brow-ridges, elongated crania. Brain capacity reduction, flatter faces, smaller teeth, smaller noses, lighter bones, smaller thoracic capacity,

Suggests H. sapiens was more terrestrial than earlier Homo.

 

Present – future? Anthropocene: Global warming, global climate fluctuations, sea-level rise, mass extinction events…where next?

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 18, 2022 10:57 AM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Homo sapiens is, if anything, more aquatic than Homo erectus.

 

 

"As far back as 17 March 1960, Professor Sir Alister Hardy noted in The New Scientist that modern humans have many features that suggest an aquatic phase in our evolution at some time in the distant past.  

The assumption was that a group of primates became isolated on an island or some other inaccessible waterside environment and survived by becoming adapted to a semi-aquatic lifestyle in the course of that single evolutionary event. Subsequent discoveries have provided data that both support and contradict that hypothesis. 

The present investigation proposes an alternative model whereby, over millions of years, a series of emergencies, in the shape of climate fluctuations, from fertile to desert conditions and coinciding with glacial and interglacial epochs, repeatedly imposed very stringent survival pressures on every group of hominids. From the late Miocene onward, scores of such events dictated the selection criteria for gradual adaptation to an opportunistic aquatic diet in a punctuated series of evolutionary steps. 

These adaptations were cumulative, and the fossil record includes progressively more numerous examples of each new version of pre-human and human with the passage of time, progressively larger deposits of bivalve shells and other edible aquatic food species in shell middens, and more widely distributed locations for the stone tools needed to process them efficiently. 

This interpretation of the available evidence satisfies all the significant objections to Hardy’s theory and leads to the conclusion that, physiologically, we are more aquatic now than we have ever been, and the astonishing current world records for breath holding and free diving would seem to support that view."

 

The idea of a single, brief isolation event producing all (or any) of our aquatic adaptations was never really credible.

G.   

 


From: AAT@groups.io <AAT@groups.io> on behalf of algiskuliukas <algis@...>
Sent: Monday, April 18, 2022 10:07 AM
To: AAT@groups.io <AAT@groups.io>
Subject: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

For those of us who are open minded enough to answer Hardy's question "Was Man More Aquatic in the Past?" with a cautious affirmative, a second question follows "If, so when was that and how much?"

Having thought about this for twenty-five years and studied human evolution (MSc from UCL with distinction and PhD in human bipedal origins from UWA) I have come to the conclusion that the answer to the second question should be "very early modern Homo sapiens ca 200,000 years ago or so"... and... "not much".

Some proponents (e.g. Marc Verhaegen and Stephen Munro) would argue that a better answer would be "Homo erectus (sensu stricto) - i.e. the Asian, rather than African forms" and "that they were predominantly bottom divers."

That's quite a difference.

So, I'd like to discuss this openly to see if I have missed something. 

Let me start the ball rolling...

Marc always cites pacheostosis (heavy bones) of H. erectus as leaving "no other possibility" than bottom diving for this hominin but were their bones really that heavy? If you look at the Nariokotome boy femur, for example, it is remarkably gracile. Where are the papers in the literature that backs up this claim?

Marc also cites their pelvic shape as being platypelloid, with long femoral necks as further evidence but, again, that's not what I see in the literature. Nariokotome boy's pelvis is remarkably narrow actually, android rather than platypelloid. In any case what his platypelloidy got to do with bottom diving? Dugongs/manatees do not share this convergence. Their pelves, appear to be on their way to becoming vestigial like cetacea.

Whether they had heavy bones or not, there is undeniable evidence of significant weight bearing in the bones of Homo erectus. The tibial plate, the oval shaped distal femoral condyles, the robust femoral head, the large acetabulae with superiorly orientated lunate surface. The robust sacral body and large lumbar vertebrae all speak of an upright, walking, terrestrial striding biped - just like us. They seem to have been predominantly striding bipeds, not divers.

Please don't misunderstand me. I am not suggesting that Homo erectus did not swim or dive - just that they didn't do so very much, and specifically, not as much as we modern human did, or still do.

When Homo erectus reached the islands of Java and Flores some 1.8 million years ago, they could have done so without getting their feet wet as the current archipelago of Indonesia has been connected via land bridges from time to time. Of course, I have no doubt they often went swimming and diving in coastal shallows but, if they were as adept as Marc suggests (a predominantly bottom diver, remember) then it is remarkable that the narrow strait of water between Bali and Lombok across the Wallace line, just 20km wide, was never crossed by these diving hominins in 1.8 million years. If they did cross, they would have certainly populated the whole of the Australasian continent as that too was all joined by land at various times since. And yet we so no evidence of any human like species in Australia until 60,000 ago or so.

I must remind that modern humans regularly swim across such stretches of open water. The Perth - Rottnest swim is run every year and has thousands of participants. (https://en.wikipedia.org/wiki/Rottnest_Channel_Swim#:~:text=The%20distance%20is%2019.7%20km,teams%20of%20two%20or%20four.) It is about the same distance as Bali - Lombok via Penida. And of course far greater distances have been crossed than that, such as the Channel between England and France.

Of course, absence of evidence is not evidence of absence but, it seems to me that if we are to remain true to scientific principles we must base our ideas on evidence and here, the evidence is that Homo sapiens is, if anything, more aquatic than Homo erectus.

Algis Kuliukas
Perth
April 2022


Re: Homo erectus (sensu stricto) the most aquatically adapted hominin?

fceska_gr
 

Hi Gareth,

 

Would it be possible to reveal the source of this text, please? I’d like to read it.

 

I agree that climate has influenced anthropoid evolution at many stages and in different ways, although I don’t believe sapiens are the most aquatic. I think early Homo was more aquatic than we are now.

 

If we look at the evidence, many of our “aquatic” adaptations stretch back at least as far as the early Miocene and most of the changes seem to be instigated by climatic changes.  

 

[1st aquatic stage: Hominoidea]

30-25 Ma Climate: very hot, humid, subtropical forests; tectonic upheaval and rifting causing vast areas of East Africa to become flooded, creating forested islands in vast East African lakes.

25-20 Ma: orthograde body plan and modifications towards bipedal posture, suspensory adaptations of the wrist, hand, shoulders and arms, larger, wider thorax, loss of tail, etc.
20 – 14 Ma: gradual increase in size from small-bodied primates to large chimp sized apes

Some time between 25 Ma and 16 Ma: partial loss of pelage (great apes relative to macaques)

Overall increase in eccrine gland distribution (between OWMs and apes)

Probable reduction in olfactory ability

PNS

c. 18- 16 Ma Hylobatidae diverge

 

16-14 Ma: Climate: temperature decrease, reduced humidity & loss of biodiversity in Africa; increasing biodiversity, humid sub-tropical forests & vast bodies of water in Eurasia, land bridges between the two continents. Disappearance of most apes from Africa. Appearance of many ape species in Eurasia.

15 Ma: loss of uricase mutation and the ability to store sugars as fat

 

[Hominidae]

15-13 Ma: the ability to fashion stone tools

c. 15-14 Ma: Pongo diverges

14 Ma: plantigrade locomotion (quadrupedal)

12-11 Ma: loss of prognathism, robust jaws, postural bipedalism (wading)

11-9 Ma: Vallesian crisis causes the extinction of many apes (loss of forests, loss of edible fruits, spreading grasslands, seasonal food availability).

10-7 Ma: bipedal hominids roam the river valleys & great lakes of southern Europe & the Tethys-Med coasts.
Smaller, more thickly enamelled dentition – change of diet.

 

[Homininae]

10-6 Ma: terrestrial bipedalism develops

c. 10-8 Ma: gorilla divergence

7 Ma: human-like P4 dental root morphology

6 Ma: human-like foot morphology (loss of arborealism)

 

6-5 Ma: Pan / Homo diverge

5.9 – 5.3 Ma: Mediterranean Salinity Crisis: great unidirectional migrations of fauna away from the southern Med, towards Africa.

5.3 Ma: Zanclean Megaflood cuts off land bridge between Eurasia and Africa.

Pliocene: 5.3 – 2.6 Ma. Sea-levels rise by up to 30 m. Hyper aridity in the Arabian Peninsula prevents migration of fauna eastwards.

During much of this period, the Arabian Peninsula is effectively cut off from the rest of the world.

 

4-3 Ma (PTERV1 virus throughout Africa, affects all African apes, but not Homo or Orangutans)

 

[Panini / Australopithecines]

Climate: Loss of forests and wetlands, increase of savannah and mosaic environments

5-2 Ma: Gradual reversal from upright bipedalism towards arborealism, and eventually, knucklewalking (also in Gorilla – homoplasy).

 

[Early Homo]

2.6 – 2.0 Ma: Pleistocene cooling, sea-level decrease, vast intercontinental shelves appear, land bridges, intertidal zones, migration routes

2.0 Ma: Homo appears: taller, larger with longer legs, increased thoracic capacity, heavier leg bones, heavier crania, larger brain (significant development of cortex associated with vision and manual dexterity), improved dexterity, platycephaly, hooded nose, thick brow ridges, improved shoulder rotation, no evidence of sexual dimorphism
More sophisticated stone tool use, shellfish consumption.

 

[Later Homo]

2.6 Ma – 2.0 Ka: Pleistocene cooling, sea-level decrease, fluctuating temperatures (between glacials).

Ear exostoses, larger brains, heavy bones, multiple crania fractures, larger eyes (cold-water diving?)

 

[Homo sapiens]

300 Ka – present: Holocene (relatively stable climate, less overall humidity)

More gracile forms (taller, thinner – like waders), rounder crania, shorter femoral necks (adaptation for running). Loss of platycephaly, heavy brow-ridges, elongated crania. Brain capacity reduction, flatter faces, smaller teeth, smaller noses, lighter bones, smaller thoracic capacity,

Suggests H. sapiens was more terrestrial than earlier Homo.

 

Present – future? Anthropocene: Global warming, global climate fluctuations, sea-level rise, mass extinction events…where next?

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 18, 2022 10:57 AM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

Homo sapiens is, if anything, more aquatic than Homo erectus.

 

 

"As far back as 17 March 1960, Professor Sir Alister Hardy noted in The New Scientist that modern humans have many features that suggest an aquatic phase in our evolution at some time in the distant past.  

The assumption was that a group of primates became isolated on an island or some other inaccessible waterside environment and survived by becoming adapted to a semi-aquatic lifestyle in the course of that single evolutionary event. Subsequent discoveries have provided data that both support and contradict that hypothesis. 

The present investigation proposes an alternative model whereby, over millions of years, a series of emergencies, in the shape of climate fluctuations, from fertile to desert conditions and coinciding with glacial and interglacial epochs, repeatedly imposed very stringent survival pressures on every group of hominids. From the late Miocene onward, scores of such events dictated the selection criteria for gradual adaptation to an opportunistic aquatic diet in a punctuated series of evolutionary steps. 

These adaptations were cumulative, and the fossil record includes progressively more numerous examples of each new version of pre-human and human with the passage of time, progressively larger deposits of bivalve shells and other edible aquatic food species in shell middens, and more widely distributed locations for the stone tools needed to process them efficiently. 

This interpretation of the available evidence satisfies all the significant objections to Hardy’s theory and leads to the conclusion that, physiologically, we are more aquatic now than we have ever been, and the astonishing current world records for breath holding and free diving would seem to support that view."

 

The idea of a single, brief isolation event producing all (or any) of our aquatic adaptations was never really credible.

G.   

 


From: AAT@groups.io <AAT@groups.io> on behalf of algiskuliukas <algis@...>
Sent: Monday, April 18, 2022 10:07 AM
To: AAT@groups.io <AAT@groups.io>
Subject: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

For those of us who are open minded enough to answer Hardy's question "Was Man More Aquatic in the Past?" with a cautious affirmative, a second question follows "If, so when was that and how much?"

Having thought about this for twenty-five years and studied human evolution (MSc from UCL with distinction and PhD in human bipedal origins from UWA) I have come to the conclusion that the answer to the second question should be "very early modern Homo sapiens ca 200,000 years ago or so"... and... "not much".

Some proponents (e.g. Marc Verhaegen and Stephen Munro) would argue that a better answer would be "Homo erectus (sensu stricto) - i.e. the Asian, rather than African forms" and "that they were predominantly bottom divers."

That's quite a difference.

So, I'd like to discuss this openly to see if I have missed something. 

Let me start the ball rolling...

Marc always cites pacheostosis (heavy bones) of H. erectus as leaving "no other possibility" than bottom diving for this hominin but were their bones really that heavy? If you look at the Nariokotome boy femur, for example, it is remarkably gracile. Where are the papers in the literature that backs up this claim?

Marc also cites their pelvic shape as being platypelloid, with long femoral necks as further evidence but, again, that's not what I see in the literature. Nariokotome boy's pelvis is remarkably narrow actually, android rather than platypelloid. In any case what his platypelloidy got to do with bottom diving? Dugongs/manatees do not share this convergence. Their pelves, appear to be on their way to becoming vestigial like cetacea.

Whether they had heavy bones or not, there is undeniable evidence of significant weight bearing in the bones of Homo erectus. The tibial plate, the oval shaped distal femoral condyles, the robust femoral head, the large acetabulae with superiorly orientated lunate surface. The robust sacral body and large lumbar vertebrae all speak of an upright, walking, terrestrial striding biped - just like us. They seem to have been predominantly striding bipeds, not divers.

Please don't misunderstand me. I am not suggesting that Homo erectus did not swim or dive - just that they didn't do so very much, and specifically, not as much as we modern human did, or still do.

When Homo erectus reached the islands of Java and Flores some 1.8 million years ago, they could have done so without getting their feet wet as the current archipelago of Indonesia has been connected via land bridges from time to time. Of course, I have no doubt they often went swimming and diving in coastal shallows but, if they were as adept as Marc suggests (a predominantly bottom diver, remember) then it is remarkable that the narrow strait of water between Bali and Lombok across the Wallace line, just 20km wide, was never crossed by these diving hominins in 1.8 million years. If they did cross, they would have certainly populated the whole of the Australasian continent as that too was all joined by land at various times since. And yet we so no evidence of any human like species in Australia until 60,000 ago or so.

I must remind that modern humans regularly swim across such stretches of open water. The Perth - Rottnest swim is run every year and has thousands of participants. (https://en.wikipedia.org/wiki/Rottnest_Channel_Swim#:~:text=The%20distance%20is%2019.7%20km,teams%20of%20two%20or%20four.) It is about the same distance as Bali - Lombok via Penida. And of course far greater distances have been crossed than that, such as the Channel between England and France.

Of course, absence of evidence is not evidence of absence but, it seems to me that if we are to remain true to scientific principles we must base our ideas on evidence and here, the evidence is that Homo sapiens is, if anything, more aquatic than Homo erectus.

Algis Kuliukas
Perth
April 2022


Re: Italian Hn dived for shellfish

alandarwinvanarsdale
 

The most recent Neanderthal lithic tradition in Italy has been reassigned to EEMH based upon human fossils. In many parts of Italy the Mousterian and / or Achuelian never happened with other lithic traditions in their place. Usually there is no fossil evidence associated with lithic traditions in Italy. It is likely at least some of the “neanderthals” who were more actively diving were early modern humans or EEMH not neanderthals.

 

Sent from Mail for Windows

 

From: Marc Verhaegen
Sent: Monday, April 18, 2022 7:45 AM
To: AAT@groups.io
Subject: [AAT] Italian Hn dived for shellfish

 

Neandertals on the beach:

Use of marine resources at Grotta dei Moscerini (Latium, Italy)

Paola Villa  cs 2020  PLoS One  15:e0226690

doi 10.1371/journal.pone.0226690.

 

Excavated in 1949, Grotta dei Moscerini (MIS-5 to early MIS-4) is 1 of 2

Italian Hn sites with a large assemblage of  retouched shells (n=171)

from 21 layers.

The other occurrence is from  the broadly contemporaneous layer L of

Grotta del Cavallo, S-Italy (n=126).

8 other Mousterian sites in Italy & 1in Greece  also have shell tools,

but in a very small number.

The shell tools are  made on valves of the smooth clam Callista chione.

 

The general idea that  the valves of Callista chione were collected by

Hn on the  beach after the death of the mollusk is incomplete.

At Moscerini, 23.9 %  of the spms were gathered directly from the

sea-floor, as live  animals by skin diving Hn.

Archaeological data from sites in  Italy, France & Spain confirm that

shell-fishing & fresh-water fishing was a common Hn activity, as

indicated by anatomical  studies recently published by E.Trinkaus.

Lithic analysis provides data to show the relation between stone tools &

shell tools.

Several  layers contain pumices derived from volcanic eruptions in the

Ischia  Island or the Campi Flegrei (prior to the Campanian Ignimbrite

mega-eruption).

Their rounded edges indicate:

they were transported  by sea-currents to the beach at the base of the

Moscerini sequence.

 

Their presence in the occupation layers above the beach is discussed.

The most plausible hypothesis is that they were collected by  Hn.

Incontrovertible evidence that Hn collected  pumices is provided by a

cave in Liguria.

Use of pumices as abraders is  well documented in the Upper Paleolithic.

We prove:

the exploitation  of submerged aquatic resources & the collection of

pumices common in  the UP were part of Hn behavior well before Hs

arrival in W-Europe.

 

 

 

 

 

 

 


Italian Hn dived for shellfish

Marc Verhaegen
 

Neandertals on the beach:
Use of marine resources at Grotta dei Moscerini (Latium, Italy)
Paola Villa cs 2020 PLoS One 15:e0226690
doi 10.1371/journal.pone.0226690.

Excavated in 1949, Grotta dei Moscerini (MIS-5 to early MIS-4) is 1 of 2 Italian Hn sites with a large assemblage of retouched shells (n=171) from 21 layers.
The other occurrence is from the broadly contemporaneous layer L of Grotta del Cavallo, S-Italy (n=126).
8 other Mousterian sites in Italy & 1in Greece also have shell tools, but in a very small number.
The shell tools are made on valves of the smooth clam Callista chione.

The general idea that the valves of Callista chione were collected by Hn on the beach after the death of the mollusk is incomplete.
At Moscerini, 23.9 % of the spms were gathered directly from the sea-floor, as live animals by skin diving Hn.
Archaeological data from sites in Italy, France & Spain confirm that shell-fishing & fresh-water fishing was a common Hn activity, as indicated by anatomical studies recently published by E.Trinkaus.
Lithic analysis provides data to show the relation between stone tools & shell tools.
Several layers contain pumices derived from volcanic eruptions in the Ischia Island or the Campi Flegrei (prior to the Campanian Ignimbrite mega-eruption).
Their rounded edges indicate:
they were transported by sea-currents to the beach at the base of the Moscerini sequence.

Their presence in the occupation layers above the beach is discussed.
The most plausible hypothesis is that they were collected by Hn.
Incontrovertible evidence that Hn collected pumices is provided by a cave in Liguria.
Use of pumices as abraders is well documented in the Upper Paleolithic.
We prove:
the exploitation of submerged aquatic resources & the collection of pumices common in the UP were part of Hn behavior well before Hs arrival in W-Europe.

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