Date   

Re: Zinjanthropus afarensis->boisei

alandarwinvanarsdale
 

Land is rising and falling over time same as sea levels. If you find marine deposits you know the ocean was there at that time and place. Predicting when Islands were connected to Mainlands is tricky and not always certain. However geologists doing this do know what they are doing and this is a branch of geology a lot of effort has been put into. ______________________________________________________________________________________________________If there is no deep water between an Island and the Mainland it likely has been connected a number of times and around 100kya or more recently. Flores has not been connected to the Mainland within the last 5 million years and Crete was connected at times. I have read the actual literature on these issues and am able to understand it. ______________________________________________________________________________________________________It has been grossly underestimated a to the ability of Hominids in general to cross bodies of water including in sight of the Mainland Islands. We do not actually need land bridges to explain initial settlements or gene flow after the fact of settlement. This relates to the strong past biases against AAT.

 

Sent from Mail for Windows

 

From: Gareth Morgan
Sent: Monday, April 25, 2022 9:40 AM
To: AAT@groups.io
Subject: Re: [AAT] Zinjanthropus afarensis->boisei

 

Always hard to tell how much is guesswork with these bold statements, especially when they are made in support of a theory about the "chronicle of dispersal" of tiny insects many millions of years ago. Is the sea level evidence presented to support the dispersal theory, or is the apparent distribution of the insects presented as evidence for higher sea levels?

 

If sea levels were high enough to cover Syria and most of Italy ( current altitude ca 500metres) in the middle and late Miocene, why was most of the Sahara (alt. ca. 200 m.)not also flooded? 

 

I reckon you can make any guesses you want to fit any theory and no one can contradict you.

 

G.

From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Monday, April 25, 2022 6:02 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Zinjanthropus afarensis->boisei

 

Thanks Gareth,

 

These maps clearly shows Crete was part of the mainland at least till 12 Ma but completely separate by 8 Ma. It clearly rejoined during the MSC, between 5.9 – 5.3 Ma.
Those who have written about Trachilos claim it was still part of the Greek mainland when those prints were left 6 Ma, but I don’t see how it could have been.

 

(Sorry, I’ve shared these before to the group).  

 

From:

The Scolopendra species (Chilopoda: Scolopendromorpha: Scolopendridae) of Greece (E-Mediterranean): a theoretical approach on the effect of geography and palaeogeography on their distribution

https://www.academia.edu/37505816/The_Scolopendra_species_Chilopoda_Scolopendromorpha_Scolopendridae_of_Greece_E_Mediterranean_a_theoretical_approach_on_the_effect_of_geography_and_palaeogeography_on_their_distribution

 

 

Neogene supradetachment basin development on Crete (Greece) during exhumation of the South Aegean core complex

https://www.researchgate.net/publication/263381698_Neogene_supradetachment_basin_development_on_Crete_Greece_during_exhumation_of_the_South_Aegean_core_complex

 

Hence, three main tectonic phases are recognised: (1) Early to Middle Miocene N–S extension formed during the Cretan detachment, exhumed in the South Aegean core complex. The Cretan detachment remained active until 11–10 Ma, based on the oldest sediments that unconformably overlie the metamorphic rocks. Successions older than 11–10 Ma unconformably overlie only the hanging wall of the Cretan detachment, and do not contain fragments of the footwall rocks; they therefore predate the oldest exposure of the metamorphic rocks of the footwall. The hanging wall rocks and Middle Miocene sediments form isolated blocks on top of the exhumed metamorphic rocks, which are interpreted as extensional klippen. (2) From approximately 10 Ma onward, southward migration of the area that presently covers Crete was accompanied by E–W extension, and the opening of the Sea of Crete to the north. Contemporaneously, large folds with WNW–ESE striking, NNE dipping axial planes developed, possibly in response to sinistral transpression. (3) During the Pliocene, Crete emerged and tilted to the NNW, probably as a result of left-lateral transpression in the Hellenic fore-arc, induced by the collision with the African promontory.

 

Mammal faunas reported by De Bruijn et al. (1971) and De Bruijn & Meulenkamp (1972) led Drooger & Meulen-kamp (1973) to suggest that the connection of Crete to the European mainland was lost in the course of the early Tortonian, as a result of the onset of foundering of the Cretan Basin underlying the Sea of Crete (Fig. 8).We follow this conclusion, as it is in line with the fact that the youngest sediments that provide evidence for a northern sediment source are the deep-marine early Tortonian sediments in the Ierapetra area (Kalamavka, Section 64; Fortuin, 1978; Fortuin & Peters, 1984).

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 25, 2022 2:08 PM
To: AAT@groups.io
Subject: Re: [AAT] Zinjanthropus afarensis->boisei

 

Crete was an island at that time?

 

I've wondered about this. The water between Crete and mainland Greece is about 100 m deep today in the shallowest places.

 

 

Water levels would have been lower during the Messinian and probably other times, but there is also evidence that the whole area has been sliding downwards and to the west.

 

 

These earthquakes (brown pixels)...https://sp.lyellcollection.org/content/291/1/1

 

 

are related to this movement, south westward. 

 

 

 

From the top picture, we can see that the whole Aegean basin would be sliding down into deeper water with every tremor.

 

So I can happily accept that Crete and the sea bed around it would have been higher in the past, which would provide land bridges to the mainland, if not continuous dry land. There have, I believe, been a number of cities discovered on the sea floor in the area that must once have been on dry land.

 

The sea to the south of Crete is 2,000 m deep, so I don't think a land bridge to Africa is feasible.

 

G.

 

From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Monday, April 25, 2022 12:28 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Zinjanthropus afarensis->boisei

 

Yes, Madelaine Bohme's book "Ancient Bones" is really good. I read it last year (well, I listened to it on Audible). She is also proposing a possible connection between Graecopithecus as LCA / oldest hominin and Trachilos (original hominins).

But in this book, as elsewhere, she says that Crete was connected to the mainland of Greece when the Trachilos footprints were left there 6.0 Ma. I have found geological evidence (and previously shared here with maps) showing that Crete was an island at that time. I have searched around and find conflicting information. If anyone can find evidence one way or another please let me know. I think it's an important thing to know regarding Trachilos.

Francesca


-----Original Message-----
From: AAT@groups.io <AAT@groups.io> On Behalf Of Marc Verhaegen
Sent: Sunday, April 24, 2022 2:14 PM
To: aat@groups.io
Subject: [AAT] Zinjanthropus afarensis->boisei

I'm reading Madelaine Boehme "Wie wir Menschen werden" (in Dutch transl.), very interesting: dryopiths, Trachilos, Graecopith.etc.
It reminded me that the first generic name given to boisei was Zinjanthropus.
Detailed comparisons (e.g. my Hum.Evol.papers) suggest E & S.African apiths evolved in parellel from Pliocene "gracile" to Pleistocene
"robust":
I suggested  Praeanthropus afarensis->boisei, fossil subgenus belonging to Gorilla  //  Australopithecus africanus->robustus, fossil subgenus of Pan, but the name Zinjanthropus is older & more specific, and should here be preferred to Praeanthropus?









 


Re: Nasopharyngeal morphology contributes to understanding the “muddle in the middle” of the Pleistocene hominin fossil record

alandarwinvanarsdale
 

The muddle in the middle is a muddle in the same sense as the fantasy taxa modern humans and AMHs (Wolpoff noted these are fantasy taxa). Naming taxa with the assumption of the usually false linear evolution model is axiomatic, leads to these types of problems. ________________________________________________________________________________________________________All “taxa” of Homo are unified by the spread of particular traits, not a result of linear evolution with “replacement” or “essential replacement”. AMHs is unified only by the spread, through introgression, to all extant humans of the greatly enlarged Broca area. Modern humans only by a relatively small mid face, a usually but not always vertical forehead, a usually but not always relatively well rounded cranium, usually but not always relatively gracile hands, and the last premolar relative to the first molar small (in the last trait archaic pygmies also have this trait). ___________________________________________________________________________________________________The “muddle in the middle” is the spread of genes (by introgressions) related to modern sized human brains. If they want to throw away skeletons in the closet of OoA then they will need to throw everything out, as none of it complies to standards in modern biology. Not like society will accept a full revision at this time, so we are left with working with what we have, a system which is deeply broken but can be revised until usable. If they do not like 19th century grade typology that does not mean they can just pick and choose which revisions to make in order to name yet more “new species”. Rules need to be consistent, it is no revision at all, just more of the same comedy.

 

Sent from Mail for Windows

 

From: Stephen Munro
Sent: Monday, April 25, 2022 5:10 PM
To: AAT@groups.io
Subject: [AAT] Nasopharyngeal morphology contributes to understanding the “muddle in the middle” of the Pleistocene hominin fossil record

 

The late archeologist Glynn Isaac first applied the term “muddle in the middle” to a poorly understood period in the Middle Pleistocene human fossil record. This study uses the nasopharyngeal boundar...

anatomypubs.onlinelibrary.wiley.com

 

The late archeologist Glynn Isaac first applied the term “muddle in the middle” to a poorly understood period in the Middle Pleistocene human fossil record. This study uses the nasopharyngeal boundaries as a source of traits that may inform this unclear period of human evolution. The nasopharynx lies at the nexus of several vital physiological systems, yet relatively little is known about its importance in human evolution. We analyzed a geographically diverse contemporary Homo sapiens growth series (n = 180 adults, 237 nonadults), Homo neanderthalensis (La Chapelle aux Saints 1, La Ferrassie 1, Forbes Quarry 1, Monte Circeo 1, and Saccopastore 1), mid-Pleistocene Homo (Atapuerca 5, Kabwe 1, Petralona 1, and Steinheim 1), and two Homo erectus sensu lato (KNM-ER 3733 and Sangiran 17). Methods include traditional (Analysis 1) and 3D geometric morphometric analysis (Analysis 2). Herectus exhibited tall, narrow nasopharyngeal shape, a robust, ancestral morphology. Kabwe 1 and Petralona 1 plotted among H. sapiens in Analysis 2, exhibiting relatively shorter and vertical cartilaginous Eustachian tubes and vertical medial pterygoid plates. Atapuerca 5 and Steinheim 1 exhibited horizontal vomeral orientation similar to H. neanderthalensis, indicating greater relative soft palate length and anteroposterior nasopharynx expansion. They may exhibit synapomorphies with H. neanderthalensis, supporting the accretionary hypothesis. Species-level differences were found among H. sapiens and H. neanderthalensis, including relatively longer dilator tubae muscles and extreme facial airorhynchy among Neanderthals. Furthermore, H. neanderthalensis were autapomorphic in exhibiting horizontal pterygoid plate orientation similar to human infants, suggesting that they may have had inferiorly low placement of the torus tubarius and Eustachian tube orifice on the lateral nasopharyngeal wall in life. This study supports use of osseous nasopharyngeal boundaries both for morphological characters and understanding evolution of otitis media susceptibility in living humans.

 


Nasopharyngeal morphology contributes to understanding the “muddle in the middle” of the Pleistocene hominin fossil record

Stephen Munro
 

The late archeologist Glynn Isaac first applied the term “muddle in the middle” to a poorly understood period in the Middle Pleistocene human fossil record. This study uses the nasopharyngeal boundar...
anatomypubs.onlinelibrary.wiley.com

The late archeologist Glynn Isaac first applied the term “muddle in the middle” to a poorly understood period in the Middle Pleistocene human fossil record. This study uses the nasopharyngeal boundaries as a source of traits that may inform this unclear period of human evolution. The nasopharynx lies at the nexus of several vital physiological systems, yet relatively little is known about its importance in human evolution. We analyzed a geographically diverse contemporary Homo sapiens growth series (n = 180 adults, 237 nonadults), Homo neanderthalensis (La Chapelle aux Saints 1, La Ferrassie 1, Forbes Quarry 1, Monte Circeo 1, and Saccopastore 1), mid-Pleistocene Homo (Atapuerca 5, Kabwe 1, Petralona 1, and Steinheim 1), and two Homo erectus sensu lato (KNM-ER 3733 and Sangiran 17). Methods include traditional (Analysis 1) and 3D geometric morphometric analysis (Analysis 2). H. erectus exhibited tall, narrow nasopharyngeal shape, a robust, ancestral morphology. Kabwe 1 and Petralona 1 plotted among H. sapiens in Analysis 2, exhibiting relatively shorter and vertical cartilaginous Eustachian tubes and vertical medial pterygoid plates. Atapuerca 5 and Steinheim 1 exhibited horizontal vomeral orientation similar to H. neanderthalensis, indicating greater relative soft palate length and anteroposterior nasopharynx expansion. They may exhibit synapomorphies with H. neanderthalensis, supporting the accretionary hypothesis. Species-level differences were found among H. sapiens and H. neanderthalensis, including relatively longer dilator tubae muscles and extreme facial airorhynchy among Neanderthals. Furthermore, H. neanderthalensis were autapomorphic in exhibiting horizontal pterygoid plate orientation similar to human infants, suggesting that they may have had inferiorly low placement of the torus tubarius and Eustachian tube orifice on the lateral nasopharyngeal wall in life. This study supports use of osseous nasopharyngeal boundaries both for morphological characters and understanding evolution of otitis media susceptibility in living humans.


Re: Zinjanthropus afarensis->boisei

Gareth Morgan
 

Always hard to tell how much is guesswork with these bold statements, especially when they are made in support of a theory about the "chronicle of dispersal" of tiny insects many millions of years ago. Is the sea level evidence presented to support the dispersal theory, or is the apparent distribution of the insects presented as evidence for higher sea levels?

If sea levels were high enough to cover Syria and most of Italy ( current altitude ca 500metres) in the middle and late Miocene, why was most of the Sahara (alt. ca. 200 m.)not also flooded? 

I reckon you can make any guesses you want to fit any theory and no one can contradict you.

G.


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Monday, April 25, 2022 6:02 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Zinjanthropus afarensis->boisei
 

Thanks Gareth,

 

These maps clearly shows Crete was part of the mainland at least till 12 Ma but completely separate by 8 Ma. It clearly rejoined during the MSC, between 5.9 – 5.3 Ma.
Those who have written about Trachilos claim it was still part of the Greek mainland when those prints were left 6 Ma, but I don’t see how it could have been.

 

(Sorry, I’ve shared these before to the group).  

 

From:

The Scolopendra species (Chilopoda: Scolopendromorpha: Scolopendridae) of Greece (E-Mediterranean): a theoretical approach on the effect of geography and palaeogeography on their distribution

https://www.academia.edu/37505816/The_Scolopendra_species_Chilopoda_Scolopendromorpha_Scolopendridae_of_Greece_E_Mediterranean_a_theoretical_approach_on_the_effect_of_geography_and_palaeogeography_on_their_distribution

 

 

Neogene supradetachment basin development on Crete (Greece) during exhumation of the South Aegean core complex

https://www.researchgate.net/publication/263381698_Neogene_supradetachment_basin_development_on_Crete_Greece_during_exhumation_of_the_South_Aegean_core_complex

 

Hence, three main tectonic phases are recognised: (1) Early to Middle Miocene N–S extension formed during the Cretan detachment, exhumed in the South Aegean core complex. The Cretan detachment remained active until 11–10 Ma, based on the oldest sediments that unconformably overlie the metamorphic rocks. Successions older than 11–10 Ma unconformably overlie only the hanging wall of the Cretan detachment, and do not contain fragments of the footwall rocks; they therefore predate the oldest exposure of the metamorphic rocks of the footwall. The hanging wall rocks and Middle Miocene sediments form isolated blocks on top of the exhumed metamorphic rocks, which are interpreted as extensional klippen. (2) From approximately 10 Ma onward, southward migration of the area that presently covers Crete was accompanied by E–W extension, and the opening of the Sea of Crete to the north. Contemporaneously, large folds with WNW–ESE striking, NNE dipping axial planes developed, possibly in response to sinistral transpression. (3) During the Pliocene, Crete emerged and tilted to the NNW, probably as a result of left-lateral transpression in the Hellenic fore-arc, induced by the collision with the African promontory.

 

Mammal faunas reported by De Bruijn et al. (1971) and De Bruijn & Meulenkamp (1972) led Drooger & Meulen-kamp (1973) to suggest that the connection of Crete to the European mainland was lost in the course of the early Tortonian, as a result of the onset of foundering of the Cretan Basin underlying the Sea of Crete (Fig. 8).We follow this conclusion, as it is in line with the fact that the youngest sediments that provide evidence for a northern sediment source are the deep-marine early Tortonian sediments in the Ierapetra area (Kalamavka, Section 64; Fortuin, 1978; Fortuin & Peters, 1984).

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 25, 2022 2:08 PM
To: AAT@groups.io
Subject: Re: [AAT] Zinjanthropus afarensis->boisei

 

Crete was an island at that time?

 

I've wondered about this. The water between Crete and mainland Greece is about 100 m deep today in the shallowest places.

 

 

Water levels would have been lower during the Messinian and probably other times, but there is also evidence that the whole area has been sliding downwards and to the west.

 

 

These earthquakes (brown pixels)...https://sp.lyellcollection.org/content/291/1/1

 

 

are related to this movement, south westward. 

 

 

 

From the top picture, we can see that the whole Aegean basin would be sliding down into deeper water with every tremor.

 

So I can happily accept that Crete and the sea bed around it would have been higher in the past, which would provide land bridges to the mainland, if not continuous dry land. There have, I believe, been a number of cities discovered on the sea floor in the area that must once have been on dry land.

 

The sea to the south of Crete is 2,000 m deep, so I don't think a land bridge to Africa is feasible.

 

G.

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Monday, April 25, 2022 12:28 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Zinjanthropus afarensis->boisei

 

Yes, Madelaine Bohme's book "Ancient Bones" is really good. I read it last year (well, I listened to it on Audible). She is also proposing a possible connection between Graecopithecus as LCA / oldest hominin and Trachilos (original hominins).

But in this book, as elsewhere, she says that Crete was connected to the mainland of Greece when the Trachilos footprints were left there 6.0 Ma. I have found geological evidence (and previously shared here with maps) showing that Crete was an island at that time. I have searched around and find conflicting information. If anyone can find evidence one way or another please let me know. I think it's an important thing to know regarding Trachilos.

Francesca


-----Original Message-----
From: AAT@groups.io <AAT@groups.io> On Behalf Of Marc Verhaegen
Sent: Sunday, April 24, 2022 2:14 PM
To: aat@groups.io
Subject: [AAT] Zinjanthropus afarensis->boisei

I'm reading Madelaine Boehme "Wie wir Menschen werden" (in Dutch transl.), very interesting: dryopiths, Trachilos, Graecopith.etc.
It reminded me that the first generic name given to boisei was Zinjanthropus.
Detailed comparisons (e.g. my Hum.Evol.papers) suggest E & S.African apiths evolved in parellel from Pliocene "gracile" to Pleistocene
"robust":
I suggested  Praeanthropus afarensis->boisei, fossil subgenus belonging to Gorilla  //  Australopithecus africanus->robustus, fossil subgenus of Pan, but the name Zinjanthropus is older & more specific, and should here be preferred to Praeanthropus?











Re: Zinjanthropus afarensis->boisei

fceska_gr
 

Thanks Gareth,

 

These maps clearly shows Crete was part of the mainland at least till 12 Ma but completely separate by 8 Ma. It clearly rejoined during the MSC, between 5.9 – 5.3 Ma.
Those who have written about Trachilos claim it was still part of the Greek mainland when those prints were left 6 Ma, but I don’t see how it could have been.

 

(Sorry, I’ve shared these before to the group).  

 

From:

The Scolopendra species (Chilopoda: Scolopendromorpha: Scolopendridae) of Greece (E-Mediterranean): a theoretical approach on the effect of geography and palaeogeography on their distribution

https://www.academia.edu/37505816/The_Scolopendra_species_Chilopoda_Scolopendromorpha_Scolopendridae_of_Greece_E_Mediterranean_a_theoretical_approach_on_the_effect_of_geography_and_palaeogeography_on_their_distribution

 

 

Neogene supradetachment basin development on Crete (Greece) during exhumation of the South Aegean core complex

https://www.researchgate.net/publication/263381698_Neogene_supradetachment_basin_development_on_Crete_Greece_during_exhumation_of_the_South_Aegean_core_complex

 

Hence, three main tectonic phases are recognised: (1) Early to Middle Miocene N–S extension formed during the Cretan detachment, exhumed in the South Aegean core complex. The Cretan detachment remained active until 11–10 Ma, based on the oldest sediments that unconformably overlie the metamorphic rocks. Successions older than 11–10 Ma unconformably overlie only the hanging wall of the Cretan detachment, and do not contain fragments of the footwall rocks; they therefore predate the oldest exposure of the metamorphic rocks of the footwall. The hanging wall rocks and Middle Miocene sediments form isolated blocks on top of the exhumed metamorphic rocks, which are interpreted as extensional klippen. (2) From approximately 10 Ma onward, southward migration of the area that presently covers Crete was accompanied by E–W extension, and the opening of the Sea of Crete to the north. Contemporaneously, large folds with WNW–ESE striking, NNE dipping axial planes developed, possibly in response to sinistral transpression. (3) During the Pliocene, Crete emerged and tilted to the NNW, probably as a result of left-lateral transpression in the Hellenic fore-arc, induced by the collision with the African promontory.

 

Mammal faunas reported by De Bruijn et al. (1971) and De Bruijn & Meulenkamp (1972) led Drooger & Meulen-kamp (1973) to suggest that the connection of Crete to the European mainland was lost in the course of the early Tortonian, as a result of the onset of foundering of the Cretan Basin underlying the Sea of Crete (Fig. 8).We follow this conclusion, as it is in line with the fact that the youngest sediments that provide evidence for a northern sediment source are the deep-marine early Tortonian sediments in the Ierapetra area (Kalamavka, Section 64; Fortuin, 1978; Fortuin & Peters, 1984).

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Monday, April 25, 2022 2:08 PM
To: AAT@groups.io
Subject: Re: [AAT] Zinjanthropus afarensis->boisei

 

Crete was an island at that time?

 

I've wondered about this. The water between Crete and mainland Greece is about 100 m deep today in the shallowest places.

 

 

Water levels would have been lower during the Messinian and probably other times, but there is also evidence that the whole area has been sliding downwards and to the west.

 

 

These earthquakes (brown pixels)...https://sp.lyellcollection.org/content/291/1/1

 

 

are related to this movement, south westward. 

 

 

 

From the top picture, we can see that the whole Aegean basin would be sliding down into deeper water with every tremor.

 

So I can happily accept that Crete and the sea bed around it would have been higher in the past, which would provide land bridges to the mainland, if not continuous dry land. There have, I believe, been a number of cities discovered on the sea floor in the area that must once have been on dry land.

 

The sea to the south of Crete is 2,000 m deep, so I don't think a land bridge to Africa is feasible.

 

G.

 


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Monday, April 25, 2022 12:28 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Zinjanthropus afarensis->boisei

 

Yes, Madelaine Bohme's book "Ancient Bones" is really good. I read it last year (well, I listened to it on Audible). She is also proposing a possible connection between Graecopithecus as LCA / oldest hominin and Trachilos (original hominins).

But in this book, as elsewhere, she says that Crete was connected to the mainland of Greece when the Trachilos footprints were left there 6.0 Ma. I have found geological evidence (and previously shared here with maps) showing that Crete was an island at that time. I have searched around and find conflicting information. If anyone can find evidence one way or another please let me know. I think it's an important thing to know regarding Trachilos.

Francesca


-----Original Message-----
From: AAT@groups.io <AAT@groups.io> On Behalf Of Marc Verhaegen
Sent: Sunday, April 24, 2022 2:14 PM
To: aat@groups.io
Subject: [AAT] Zinjanthropus afarensis->boisei

I'm reading Madelaine Boehme "Wie wir Menschen werden" (in Dutch transl.), very interesting: dryopiths, Trachilos, Graecopith.etc.
It reminded me that the first generic name given to boisei was Zinjanthropus.
Detailed comparisons (e.g. my Hum.Evol.papers) suggest E & S.African apiths evolved in parellel from Pliocene "gracile" to Pleistocene
"robust":
I suggested  Praeanthropus afarensis->boisei, fossil subgenus belonging to Gorilla  //  Australopithecus africanus->robustus, fossil subgenus of Pan, but the name Zinjanthropus is older & more specific, and should here be preferred to Praeanthropus?











Re: Lucy fell from a tree?

Marc Verhaegen
 


Thanks, Francesca. Whatever: tree or flood = aquarboreal: in any case not running after antelopes... :-)




------ Origineel bericht ------
Van: f-ceska@...
Aan: AAT@groups.io
Verzonden: maandag 25 april 2022 11:42
Onderwerp: Re: [AAT] Lucy fell from a tree?

According to Wikipedia, she may have died in a mudslide or flash flood:

In 2016, palaeoanthropologist John Kappelman argued that the fracturing exhibited by Lucy was consistent with a proximal humerus fracture, which is most often caused by falling in humans. He then concluded she died from falling out of a tree, and that A. afarensis slept in trees or climbed trees to escape predators. However, similar fracturing is exhibited in many other creatures in the area, including the bones of antelope, elephants, giraffes and rhinos, and may well simply be taphonomic bias (fracturing was caused by fossilisation).[66] Lucy may also have been killed in an animal attack or a mudslide.[67]

The 13 AL 333 individuals are thought to have been deposited at about the same time as one another, bear little evidence of carnivore activity, and were buried on a 7 m (23 ft) stretch of a hill. In 1981, anthropologists James Louis Aronson and Taieb suggested they were killed in a flash flood. British archaeologist Paul Pettitt considered natural causes unlikely and, in 2013, speculated that these individuals were purposefully hidden in tall grass by other hominins (funerary caching).[68] This behaviour has been documented in modern primates, and may be done so that the recently deceased do not attract predators to living grounds.[69]

F.

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Sunday, April 24, 2022 7:11 PM
To: AAT@groups.io
Subject: Re: [AAT] Lucy fell from a tree?

This is quite an old story, from 2016. A "just-so" story according to many. Certainly not anything approaching conclusive.

“The suggestion that she fell out of a tree is largely a “just-so story” that is neither verifiable nor falsifiable, and therefore unprovable.”



“If paleontologists were to apply the same logic and assertion to the many mammals whose fossilised bones have been distorted by geological forces, we would have everything from gazelles to hippos, rhinos, and elephants climbing and falling from high trees,”



The cracks on Lucy’s bones are similar to the damage seen on other early human and ancient mammal fossils throughout Africa and the rest of the world.



“Such defects created by natural geological forces of sediment pressure and mineral growth are very common in fossil assemblages. They often confuse clinicians and amateurs who imagine them to have happened around the time of death.”



“Every single element of the Lucy fossil has cracks. The authors cherry pick the ones that they imagine to be evidence of a fall from a tree, leaving the others unexplained and unexamined.”





G.




From: AAT@groups.io <AAT@groups.io> on behalf of Jack D.Barnes <needininfo@...>
Sent: Sunday, April 24, 2022 4:38 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Lucy fell from a tree?

Marc,
Great news in my opinion, another nail in the coffin, Lucy was not an ancestor. She has been one of the underpinnings for the flawed OOA (Savannah) theory. Chimps leaving West African jungles and began running around and turned into archaic humans.

Lucy was a tree-climber not a runner not a swimmer.

Greenstick fractures… why did it take a half a century to make this deduction.

-Jack


> On Apr 24, 2022, at 6:53 AM, Marc Verhaegen <m_verhaegen@...> wrote:
>
> Perimortem fractures in Lucy suggest mortality from fall out of tall tree
> John Kappelman cs 2016 Nature 537:503-7
>
> The Pliocene fossil ‘Lucy’ Au.afarensis was discovered in the Afar region (Ethiopia 1974),
> it is among the oldest & most complete fossil hominin skeletons discovered.
>
> Here we propose (close study of her skeleton):
> her cause of death was a vertical deceleration event, or impact following a fall from considerable height:
> it produced compressive & hinge (greenstick) fractures in multiple skeletal elements.
>
> Impacts that are so severe as to cause concomitant fractures usu. also damage internal organs.
> Together, these injuries are hypothesized to have caused her death.
>
> Lucy has been at the centre of a vigorous debate about the role, if any, of arboreal locomotion in early human evolution.
> It is therefore ironic that her death can be attributed to injuries resulting from a fall, probably out of a tall tree:
> it offers unusual evidence for arborealism in this species.
>
> https://www.nature.com/articles/nature19332#article-comments
>
>
>
>
>


--
Welcome to the Aquatic Ape Theory Discussion Group








Re: Zinjanthropus afarensis->boisei

Gareth Morgan
 

Crete was an island at that time?

I've wondered about this. The water between Crete and mainland Greece is about 100 m deep today in the shallowest places.



Water levels would have been lower during the Messinian and probably other times, but there is also evidence that the whole area has been sliding downwards and to the west.


These earthquakes (brown pixels)...https://sp.lyellcollection.org/content/291/1/1


are related to this movement, south westward. 




From the top picture, we can see that the whole Aegean basin would be sliding down into deeper water with every tremor.

So I can happily accept that Crete and the sea bed around it would have been higher in the past, which would provide land bridges to the mainland, if not continuous dry land. There have, I believe, been a number of cities discovered on the sea floor in the area that must once have been on dry land.

The sea to the south of Crete is 2,000 m deep, so I don't think a land bridge to Africa is feasible.

G.


From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Monday, April 25, 2022 12:28 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Zinjanthropus afarensis->boisei
 
Yes, Madelaine Bohme's book "Ancient Bones" is really good. I read it last year (well, I listened to it on Audible). She is also proposing a possible connection between Graecopithecus as LCA / oldest hominin and Trachilos (original hominins).

But in this book, as elsewhere, she says that Crete was connected to the mainland of Greece when the Trachilos footprints were left there 6.0 Ma. I have found geological evidence (and previously shared here with maps) showing that Crete was an island at that time. I have searched around and find conflicting information. If anyone can find evidence one way or another please let me know. I think it's an important thing to know regarding Trachilos.

Francesca


-----Original Message-----
From: AAT@groups.io <AAT@groups.io> On Behalf Of Marc Verhaegen
Sent: Sunday, April 24, 2022 2:14 PM
To: aat@groups.io
Subject: [AAT] Zinjanthropus afarensis->boisei

I'm reading Madelaine Boehme "Wie wir Menschen werden" (in Dutch transl.), very interesting: dryopiths, Trachilos, Graecopith.etc.
It reminded me that the first generic name given to boisei was Zinjanthropus.
Detailed comparisons (e.g. my Hum.Evol.papers) suggest E & S.African apiths evolved in parellel from Pliocene "gracile" to Pleistocene
"robust":
I suggested  Praeanthropus afarensis->boisei, fossil subgenus belonging to Gorilla  //  Australopithecus africanus->robustus, fossil subgenus of Pan, but the name Zinjanthropus is older & more specific, and should here be preferred to Praeanthropus?












Re: Lucy fell from a tree?

fceska_gr
 

According to Wikipedia, she may have died in a mudslide or flash flood:

 

In 2016, palaeoanthropologist John Kappelman argued that the fracturing exhibited by Lucy was consistent with a proximal humerus fracture, which is most often caused by falling in humans. He then concluded she died from falling out of a tree, and that A. afarensis slept in trees or climbed trees to escape predators. However, similar fracturing is exhibited in many other creatures in the area, including the bones of antelopeelephantsgiraffes and rhinos, and may well simply be taphonomic bias (fracturing was caused by fossilisation).[66] Lucy may also have been killed in an animal attack or a mudslide.[67]

The 13 AL 333 individuals are thought to have been deposited at about the same time as one another, bear little evidence of carnivore activity, and were buried on a 7 m (23 ft) stretch of a hill. In 1981, anthropologists James Louis Aronson and Taieb suggested they were killed in a flash flood. British archaeologist Paul Pettitt considered natural causes unlikely and, in 2013, speculated that these individuals were purposefully hidden in tall grass by other hominins (funerary caching).[68] This behaviour has been documented in modern primates, and may be done so that the recently deceased do not attract predators to living grounds.[69]

 

F.

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Sunday, April 24, 2022 7:11 PM
To: AAT@groups.io
Subject: Re: [AAT] Lucy fell from a tree?

 

This is quite an old story, from 2016. A "just-so" story according to many. Certainly not anything approaching conclusive.

 

 

“The suggestion that she fell out of a tree is largely a “just-so story” that is neither verifiable nor falsifiable, and therefore unprovable.”



“If paleontologists were to apply the same logic and assertion to the many mammals whose fossilised bones have been distorted by geological forces, we would have everything from gazelles to hippos, rhinos, and elephants climbing and falling from high trees,”



 The cracks on Lucy’s bones are similar to the damage seen on other early human and ancient mammal fossils throughout Africa and the rest of the world.



“Such defects created by natural geological forces of sediment pressure and mineral growth are very common in fossil assemblages. They often confuse clinicians and amateurs who imagine them to have happened around the time of death.”



 “Every single element of the Lucy fossil has cracks. The authors cherry pick the ones that they imagine to be evidence of a fall from a tree, leaving the others unexplained and unexamined.”





G.




From: AAT@groups.io <AAT@groups.io> on behalf of Jack D.Barnes <needininfo@...>
Sent: Sunday, April 24, 2022 4:38 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Lucy fell from a tree?

 

Marc,
Great news in my opinion, another nail in the coffin, Lucy was not an ancestor.  She has been one of the underpinnings for the flawed OOA (Savannah) theory.   Chimps leaving West African jungles and began running around and turned into archaic humans. 

Lucy was a tree-climber not a runner not a swimmer.

Greenstick fractures… why did it take a half a century to make this deduction. 

-Jack


> On Apr 24, 2022, at 6:53 AM, Marc Verhaegen <m_verhaegen@...> wrote:
>
> Perimortem fractures in Lucy suggest mortality from fall out of tall tree
> John Kappelman cs 2016 Nature 537:503-7
>
> The Pliocene fossil ‘Lucy’ Au.afarensis  was discovered in the Afar region (Ethiopia 1974),
> it is among the oldest & most complete fossil hominin skeletons discovered.
>
> Here we  propose (close study of her skeleton):
> her cause of death was a vertical deceleration event, or impact following a fall from considerable height:
> it produced compressive & hinge (greenstick) fractures  in multiple skeletal elements.
>
> Impacts that are so severe as to cause concomitant fractures  usu. also damage internal organs.
> Together, these injuries are hypothesized to have caused her death.
>
> Lucy  has been at the centre of a vigorous debate about the role, if any, of arboreal locomotion in early human evolution.
> It is therefore ironic  that her death can be attributed to injuries resulting from a fall,  probably out of a tall tree:
> it offers unusual evidence for arborealism in this species.
>
> https://www.nature.com/articles/nature19332#article-comments
>
>
>
>
>


--
Welcome to the Aquatic Ape Theory Discussion Group





Re: Zinjanthropus afarensis->boisei

fceska_gr
 

Yes, Madelaine Bohme's book "Ancient Bones" is really good. I read it last year (well, I listened to it on Audible). She is also proposing a possible connection between Graecopithecus as LCA / oldest hominin and Trachilos (original hominins).

But in this book, as elsewhere, she says that Crete was connected to the mainland of Greece when the Trachilos footprints were left there 6.0 Ma. I have found geological evidence (and previously shared here with maps) showing that Crete was an island at that time. I have searched around and find conflicting information. If anyone can find evidence one way or another please let me know. I think it's an important thing to know regarding Trachilos.

Francesca

-----Original Message-----
From: AAT@groups.io <AAT@groups.io> On Behalf Of Marc Verhaegen
Sent: Sunday, April 24, 2022 2:14 PM
To: aat@groups.io
Subject: [AAT] Zinjanthropus afarensis->boisei

I'm reading Madelaine Boehme "Wie wir Menschen werden" (in Dutch transl.), very interesting: dryopiths, Trachilos, Graecopith.etc.
It reminded me that the first generic name given to boisei was Zinjanthropus.
Detailed comparisons (e.g. my Hum.Evol.papers) suggest E & S.African apiths evolved in parellel from Pliocene "gracile" to Pleistocene
"robust":
I suggested Praeanthropus afarensis->boisei, fossil subgenus belonging to Gorilla // Australopithecus africanus->robustus, fossil subgenus of Pan, but the name Zinjanthropus is older & more specific, and should here be preferred to Praeanthropus?


uricase loss

Marc Verhaegen
 

volutionary history and metabolic insights of ancient mammalian uricases
James T Kratzer cs 2014 PNAS 111:3763-8 doi org/10.1073/pnas.1320393111

We have a pseudo-gene for uricase that prevents a functional enzyme from being produced.
Our inability to convert highly insoluble UA into a more soluble molecule makes us vulnerable to disease.
How & why did apes lose this functional enzyme?
Did the progressive loss of uricase activity allow our ancestors to readily accumulate fat via the metabolism of fructose from fruits?
This adaptation may have provided our ancestors with an advantage when the energy-rich rain-forests of Europe & Asia were displaced by temperate forests end-Oligocene.

Uricase (an enzyme involved in purine catabolism) is found in all 3 domains of life.
Curiously, uricase is not functional in some organisms, despite its role in converting highly insoluble UA into 5-OH-iso-urate:
apes, incl.Hs, cannot oxidize UA:
multiple, independent evol.events led to the silencing (pseudo-genization) of the uricase-gene in ancestral apes.
Why would natural selection allow the accumulation of UA, despite the physiological consequences of crystallized mono-sodium urate, acutely causing liver/kidney damage, and chronically causing gout?
We have applied evol.models to understand the history of primate uricases, by resurrecting ancestral mammalian intermediates before the pseudo-genization events of this gene-family.
Resurrected proteins reveal:
ancestral uricases have steadily decreased in activity since the mammal LCA gave rise to descendent primate lineages.
- We could determine the 3D distribution of AA-replacements, as they accumulated during evol.history by crystallizing a mammalian uricase protein.
- Ancient & modern uricases were stably transfected into HepG2 liver-cells, to test:
did uricase pseudo-genization allow ancient frugivorous apes to rapidly convert fructose into fat?
- Pharmacokinetics of an ancient uricase injected in rodents suggest:
our integrated approach provides the foundation for an evol.engineered enzyme capable of treating gout, and preventing tumor lysis syndrome in human patients.

_____

Was uricase pseudo-genization (in Miocene apes?) for bridging the winter?
and/or for making them fatter? more aquarboreal?


Re: Lucy fell from a tree?

Gareth Morgan
 

This is quite an old story, from 2016. A "just-so" story according to many. Certainly not anything approaching conclusive.


“The suggestion that she fell out of a tree is largely a “just-so story” that is neither verifiable nor falsifiable, and therefore unprovable.”

“If paleontologists were to apply the same logic and assertion to the many mammals whose fossilised bones have been distorted by geological forces, we would have everything from gazelles to hippos, rhinos, and elephants climbing and falling from high trees,”

 The cracks on Lucy’s bones are similar to the damage seen on other early human and ancient mammal fossils throughout Africa and the rest of the world.

“Such defects created by natural geological forces of sediment pressure and mineral growth are very common in fossil assemblages. They often confuse clinicians and amateurs who imagine them to have happened around the time of death.”

 “Every single element of the Lucy fossil has cracks. The authors cherry pick the ones that they imagine to be evidence of a fall from a tree, leaving the others unexplained and unexamined.”


G.


From: AAT@groups.io <AAT@groups.io> on behalf of Jack D.Barnes <needininfo@...>
Sent: Sunday, April 24, 2022 4:38 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Lucy fell from a tree?
 
Marc,
Great news in my opinion, another nail in the coffin, Lucy was not an ancestor.  She has been one of the underpinnings for the flawed OOA (Savannah) theory.   Chimps leaving West African jungles and began running around and turned into archaic humans. 

Lucy was a tree-climber not a runner not a swimmer.

Greenstick fractures… why did it take a half a century to make this deduction. 

-Jack


> On Apr 24, 2022, at 6:53 AM, Marc Verhaegen <m_verhaegen@...> wrote:
>
> Perimortem fractures in Lucy suggest mortality from fall out of tall tree
> John Kappelman cs 2016 Nature 537:503-7
>
> The Pliocene fossil ‘Lucy’ Au.afarensis  was discovered in the Afar region (Ethiopia 1974),
> it is among the oldest & most complete fossil hominin skeletons discovered.
>
> Here we  propose (close study of her skeleton):
> her cause of death was a vertical deceleration event, or impact following a fall from considerable height:
> it produced compressive & hinge (greenstick) fractures  in multiple skeletal elements.
>
> Impacts that are so severe as to cause concomitant fractures  usu. also damage internal organs.
> Together, these injuries are hypothesized to have caused her death.
>
> Lucy  has been at the centre of a vigorous debate about the role, if any, of arboreal locomotion in early human evolution.
> It is therefore ironic  that her death can be attributed to injuries resulting from a fall,  probably out of a tall tree:
> it offers unusual evidence for arborealism in this species.
>
> https://www.nature.com/articles/nature19332#article-comments
>
>
>
>
>


--
Welcome to the Aquatic Ape Theory Discussion Group






Re: Lucy fell from a tree?

 

Marc,
Great news in my opinion, another nail in the coffin, Lucy was not an ancestor. She has been one of the underpinnings for the flawed OOA (Savannah) theory. Chimps leaving West African jungles and began running around and turned into archaic humans.

Lucy was a tree-climber not a runner not a swimmer.

Greenstick fractures… why did it take a half a century to make this deduction.

-Jack

On Apr 24, 2022, at 6:53 AM, Marc Verhaegen <m_verhaegen@...> wrote:

Perimortem fractures in Lucy suggest mortality from fall out of tall tree
John Kappelman cs 2016 Nature 537:503-7

The Pliocene fossil ‘Lucy’ Au.afarensis was discovered in the Afar region (Ethiopia 1974),
it is among the oldest & most complete fossil hominin skeletons discovered.

Here we propose (close study of her skeleton):
her cause of death was a vertical deceleration event, or impact following a fall from considerable height:
it produced compressive & hinge (greenstick) fractures in multiple skeletal elements.

Impacts that are so severe as to cause concomitant fractures usu. also damage internal organs.
Together, these injuries are hypothesized to have caused her death.

Lucy has been at the centre of a vigorous debate about the role, if any, of arboreal locomotion in early human evolution.
It is therefore ironic that her death can be attributed to injuries resulting from a fall, probably out of a tall tree:
it offers unusual evidence for arborealism in this species.

https://www.nature.com/articles/nature19332#article-comments




--
Welcome to the Aquatic Ape Theory Discussion Group


Lucy fell from a tree?

Marc Verhaegen
 

Perimortem fractures in Lucy suggest mortality from fall out of tall tree
John Kappelman cs 2016 Nature 537:503-7

The Pliocene fossil ‘Lucy’ Au.afarensis was discovered in the Afar region (Ethiopia 1974),
it is among the oldest & most complete fossil hominin skeletons discovered.

Here we propose (close study of her skeleton):
her cause of death was a vertical deceleration event, or impact following a fall from considerable height:
it produced compressive & hinge (greenstick) fractures in multiple skeletal elements.

Impacts that are so severe as to cause concomitant fractures usu. also damage internal organs.
Together, these injuries are hypothesized to have caused her death.

Lucy has been at the centre of a vigorous debate about the role, if any, of arboreal locomotion in early human evolution.
It is therefore ironic that her death can be attributed to injuries resulting from a fall, probably out of a tall tree:
it offers unusual evidence for arborealism in this species.

https://www.nature.com/articles/nature19332#article-comments


Zinjanthropus afarensis->boisei

Marc Verhaegen
 

I'm reading Madelaine Boehme "Wie wir Menschen werden" (in Dutch transl.), very interesting: dryopiths, Trachilos, Graecopith.etc.
It reminded me that the first generic name given to boisei was Zinjanthropus.
Detailed comparisons (e.g. my Hum.Evol.papers) suggest E & S.African apiths evolved in parellel from Pliocene "gracile" to Pleistocene "robust":
I suggested Praeanthropus afarensis->boisei, fossil subgenus belonging to Gorilla // Australopithecus africanus->robustus, fossil subgenus of Pan,
but the name Zinjanthropus is older & more specific, and should here be preferred to Praeanthropus?


Pachyostosis PO & osteosclerosis OS in salt-water-diving tetrapods

Marc Verhaegen
 

(did I already send this?)

Bone histology in extant and fossil penguins (Aves: Sphenisciformes)
Daniel T Ksepka cs 2015
Anat.227: 611–630 doi 10.1111/joa.12367

Substantial changes in bone histology accompany the secondary adaptation to life in the water.
This transition is well documented in several lineages of mammals & non-avian reptiles,
but it has received relatively little attention in birds.
This study presents new observations on the long -bone micro-structure of penguins, based on histological sections from
- 2 extant taxa: Spheniscus & Aptenodytes,
- 8 fossil spms, belonging to stem-lineages †Palaeospheniscus & several indeterminate Eocene taxa.
High bone density in penguins results from compaction of the internal cortical tissues:
penguin bones are best considered osteo-sclerotic (OS), rather than pachy-ostotic (PO).
The oldest spms sampled in this study represent stages of penguin evolution that occurred at least 25 My after the loss of flight,
but major differences in humeral structure were observed between these Eocene stem-taxa & extant taxa:
the modification of flipper-bone micro-structure continued long after the initial loss of flight in penguins.
It is proposed:
2 key transitions occurred during the shift from the typical hollow avian humerus to the dense osteo-sclerotic humerus in penguin:
1) a reduction of the medullary cavity occurred, due to a decrease in the amount of peri-medullary osteo-clastic activity,
2) a more solid cortex was achieved by compaction.
In extant penguins & †Palaeospheniscus, most of the inner cortex is formed by rapid osteo-genesis, resulting an initial lattice-work of woven-fibered bone:
open spaces are filled by slower, centri-petal deposition of parallel-fibered bone.
Eocene stem-penguins formed the initial lattice-work, but the subsequent round of compaction was less complete:
open spaces remained in the adult bone.
In contrast to the humerus, hind-limb bones from Eocene stem-penguins had smaller medullary cavities & thus higher compactness values than extant taxa.
Cortical lines of arrested growth have been observed in extant penguins, but none was observed in any of the current sampled spms:
likely, even these ‘giant’ penguin taxa completed their growth cycle without a major pause in bone deposition:
they did not undergo a prolonged fasting interval before reaching adult size.

________

Evolution of Sirenian Pachyosteosclerosis,
a Model-case for the Study of Bone Structure in Aquatic Tetrapods
Vivian de Buffrénil cs 2010
J Mamm Evol 17:101-120
doi 10.1007/s10914-010-9130-1

OS (inner bone compaction) & PO (outer hyperplasy of bone cortices, swollen bones) are typical features of tetrapods secondarily adapted to life in water.
These peculiarities are spectacularly exemplified by the ribs of extant & extinct Sirenia:
sea-cows are the best model for studying this kind of bone structural specializations.
How did these features differentiate during sirenian evolution?
The ribs of 15 spp (from the most basal form Pezosiren portelli up to extant taxa) were studied & compared to other mammalian spp morphometrically & histologically.
-- PO was the first of these 2 specializations to occur (mid-Eocene) and is a basal feature of the Sirenia,
but it subsequently regressed in some taxa that do not exhibit hyperplasic rib cortices.
-- OS was only incipient in P.portelli. Its full development occurred later, end-Eocene.
These 2 structural specializations of bone are variably pronounced in extinct & extant Sirenia, rel.independent from each other, although frequently associated.
They are possibly due to similar hetero-chronic mechanisms bearing on the timing of osteoblast activity.
These results are discussed with respect to the functional constraints of locomotion in water.______
Research in Anatomy open access Preliminary Report:
Pachyosteosclerotic Bones in Seals
Irina Koretsky & Sulman J Rahmat 2017
doi10.31031/OARA.2017.01.000501

Despite extensive knowledge about the distribution of POS (increased bone volume & density) among some modern groups of marine mammals, this aquatic adaptation is not well known in Phocidae (true seals).
POS bones reduce buoyancy, and permit easier submergence for some marine mammals.
PO & PS are 2 vastly different bone adaptations, which have co-occurred independently (POS):
- PO describes the thickening of bone in cross-sectional area,
- OS is the replacement of cancellous bone with compact bone.
OS, PO & bone lightening consecutively occurred to various degrees as adaptations of marine mammals to different environmental niches & lifestyles.
Differing extents of POS has been demonstrated in Recent phocids, otariids & odobenids, Cetacea, Sirenia, sea-birds, fish, reptiles & other aquatic tetrapods.
There have been descriptions of POS among different modern (semi)aquatic animals,
but this osteological condition has never been studied in fossil pinnipeds (specifically in Phocidae true seals), and has not been compared with recent representatives.
Geological evidence suggests:
marine mammals have evolutionarily undergone 3 distinct stages of bone modifications.
1) OS first occurred in tetrapods secondarily adapted to life in water, seen in Sirenia & Cetacea early- to mid-Eocene ~45-50 Ma.
2) Subsequent to OS (replacement of cancellous bone with compact bone) was PO (bone thickening), which appeared from the mid-Eocene.
All lineages of aquatic tetrapods went through OS & PO during the initial stages of aquatic adaptation.
3) The 3rd stage of bone modification was an osteoporotic-like skeletal lightening, occurring only in advanced evolutionary stages as an adaptation for deep diving & fast swimming.
Cetacea exhibits such light bones.
During preliminary examination, the first 2 stages of bone modification (OS & PO) are observed among both extinct & extant seals, extinct walruses & Sirenia.
Most likely, POS served as a hydrostatic adaptation (ballast), maintaining static equilibrium in water, during the transition from terrestrial to aquatic life.
Demonstration of variability in bone density is observed in 2 modern spp of seals:
- Pusa hispida ringed seal,
- Pagophilus groenlandicus harp seal.
These 2 taxa are morphologically distinguishable:
- Pusa hispida has dense (increased compact bone), POS bones,
- Pag.groenlandicus has lighter (more cancellous bone), OS bones.
This difference may in part be explained by the diets of these 2 spp & their diving habits:
- Pusa hispida feeds on cod, herring, smelt, whitefish, sculpin, perch & other organisms primarily found in shallow Arctic waters,
- Pag.groenlandicus routinely dives up to 100 m to feed on capelin, cod, halibut, herring, redfish & some crustaceans.
Thus,
- P.hispida is able to reduce buoyancy, and remain submerged underwater by having high bone density,
- Pag.groenlandicus can dive deeper, and swim faster.
Despite their sympatric populations in marine Arctic & N-most Atlantic oceans, differing diving depths of these modern seals suggest dietary disparities, due to availability of prey.

POS was observed in the bones of the 1st fossil record of the subfamily Cystophorinae:
some extinct true seals did have POS bones.
Morphological examination of these fossil postcrania (mid-Miocene, mid-Sarmatian 11.2-12.3 Ma, S-Ukraine) led to the description of a new genus:
Pachyphoca, with 2 new spp: Pachyphoca ukrainica & chapskii + a mosaic of primitive characters.
Anatomical traits were studied with corresponding morphological functionality, e.g.
the well-developed lesser trochanter of the femur in the smaller species (P.ukrainica) suggests that it was more adapted to terrestrial locomotion than its larger relative P.chapskii,
both new spp are more primitive & better adapted for terrestrial locomotion than any living representatives of the subfamily Cystophorinae.
-- The larger species P.chapskii has innominate bones with a deep, conical acetabulum,
the margins of the acetabular fossa are raised high above the plane surface of the bone.
-- In contrast, the smaller P.ukrainica has:
- a pubis with a big, well-developed ridge for attachment of the obturator muscles (which cause outward rotation of the hip joint),
- a thick, wide & robust ischial spine for attachment of the biceps femoris muscle (hip extensor),
- a deep fossa on the medial aspect of the ilium for attachment of the gluteus medius muscle (also a hip extensor).
Discussion:
Koretsky [17] briefly detailed that some fossil postcrania of seals demonstrate thick & swollen (POS) bones that can be mistaken for those of Sirenia such as Manatus maeoticus.
If hyper-saline closed basins developed when the ancient sea in C-Europe dried out, then POS seals & Sirenia would have evolved in parallel, but separately, during the same time periods.
Increased skeletal mass would allow taxa to remain submerged for longer periods of time,
it is likely a dietary adaptation for feeding in shallow waters.
POS bones would mean that these taxa swim at slow speeds, and dive only shallow depths, suggesting that they ate slow-moving prey near the ocean floor.
POS among fossil seals is a rel.new discovery: it is hardly remarked at all in literature:
future studies are needed to determine the cause & frequency of POS in marine mammals, esp. true seals.
Upcoming morphological examinations will demonstrate:
is POS an adaptation of true seals that may have helped them successfully adjust from terrestrial to fully aquatic life & to different salinity levels?
or is there an interspecific difference in bone mass, resulting in varying dietary preferences, diving depths and/or ecological niches?
PO in fossil seals (~3-24 Ma) from the Para-Tethys (Europe) & N.America will be examined & compared to representatives of Recent seals, who present this ostological condition.
Future studies will examine diving depths, dietary specializations & ecological niches of taxa with & without POS, to demonstrate the specific cause of this condition.


early-Pleist.coastal dispersal

Marc Verhaegen
 

David MacDiarmid:
... The shadow group introgressed c 30 ka, but did’nt reach the Khoisan in S.Africa or highland E.Africa.
Introgressed Africans are very dark. E & S.Africans are not.
The latest info claims the African ghost is as distant from Denisovan as Denisovan is from Neanderthal.
Typical ratios reflected in DNA segments for archaics vs Hs are counted as single mutations:
- Hn is 202 mutations away from Hs,
- Hd denisova 384 mutations,
- Pan 1267.
These ratio’s would place the African ghost at 586 mutations away, 2.6–2.8 Ma. ...

Pleistocene Homo (erectus cs) followed Asian, European & Afr.coasts
= division in Hn, Hd, “Afr.ghost”(early-Pleist.) & Hs?


Re: Bipedalism in humans

alandarwinvanarsdale
 

Extant great apes can adapt well to bipedalism. If bipedalism begins before adulthood primates osteology in general is rather plastic and can adapt to different modes of locomotion. Many mistakes were made in OoA paleoanthropology about great ape locomotion, despite Leakey had the anthropology department include specialists in great apes taking them out of the zoology department. Great apes can learn to swim on their own if given access to water (only a few years ago all the greats were saying they could not because they can be contained by moats in zoos), great apes can stand on one leg with an unbent knee (again they were wrong only a few years ago). They ignored how Olliver moved, Olliver was the first great ape documented to move well bipedally, now there are many, including a few films of orangutans and Pan troglodytes moving well bipedally in the wild. ______________________________________________________________________________________________________________________________________________Bonobos became known only in my life time, and again the professionals failed to adapt to and understand how they move. Any bonobo researcher can tell you about 40% of bonobo time on the ground is as bipeds. Hylobatids rarely walk as bipeds, they run, and quite fast and up to about one mile. Pliopithecoids (basal monkeys closer to Old World monkeys but also with some New World monkey traits not seen in Old World monkeys), are the oldest known terrestrial bipedal primates. They seldom are found with Hominids, as they are from wetter environments than Hominids. They are also now known from Africa. _______________________________________________________________________________________________________________________________________________It has been proposed in the literature pliopithecoids, not hylobatids, are ancestral to Hominids. This appears quite unlikely. However, HGT from pliopithecoids into Hominids, or some sort of gene flow between pliopithecoids and some other monkey group (such as with affinities to Proconsul, though Proconsul itself was not ancestral to Hominids as was once thought), to generate Hominids as hybrids of two monkey groups. _____________________--------------------------OoA solved most of the great mysteries of human evolution, a linear progression in known fossils from Africa, killer apes, bipedalism being the first hominins as great apes driven away from the trees, gentle ape killer hominin, problem is, they were wrong about most things. In reality there is still a very lot unknown about human evolution, including the details of Hominid aquatic adaptations. Again today Hominin means closer to us than any living great ape, and Hominid is us and great apres together (in the 1960's the meanings were different). _______________________________________________________________________________________________________________________________________________Hylobatids are certainly the closest relatives to the Hominids. Hominids can even be understood as one small branch of hylobatids (which does bust OoA for the origin of Hominids until the find hylobatids in Africa). Hylobatids and Hominids are grades of some group of monkeys or combination of different groups of monkeys. Anyone who doubts Hominids can have monkey genes coming in after Hominids and hylobatids diverged from other monkeys should study baboon HGT genes in chimps from about 2 million years ago (when baboons were only in Sub-Sahara). Hylobatid bipedalism has been severely over-looked and under-studied by very ignorant OoA models for Hominin bipedalism. I doubt Hominin bipedalism is so simple as being directly derived from hylobatid bipedalism. More likely before Hominids diverged from hylobatids both groups already had well developed terrestrial bipedalism. And why not, since it is now well established terrestrial bipedalism beginning with the first Hominins is pure OoA fantasy, and we do not actually know when or where it first appeared in Hominids. 


On Thu, Apr 21, 2022 at 8:36 AM Jack D.Barnes <needininfo@...> wrote:
Bernard,
Bipdelism is the natural state of the stem great apes, (all great apes were bipedal, only homo retained it).

 Bipedalism was and is the natural result of the swinging motion of the Hylobates, which have never been in Africa.   How do they swing?  Feet raised forward, motionless, as the shoulder swing side to side. The lumbar section needed to twist, the tail is actually a disadvantage and hence was lost.  This required a new and still unique feature of the mammalian 5 section backbone, the lower lumbar twisting section.  It allows the Hylobates to travel 50kmh in the trees.

On the ground, running or walking Hylobates do the opposite…Holding arms and shoulders still while the hips swing side to side.  The biomechanics of their bodyplan allows them to do nothing else. Bipedal on the ground, legs motionless in the air. 

Humans also have the twisting lumbar section and it affects everything we do. freestyle in swimming, the golf swing, baseball pitching, all have shoulders turning independently of the hips.  

On the other hand Kicking a soccer ball, bipedal running and dancing all require the opposite, turning hips while maintaining the shoulders.   We are highly improved versions of the hylobate body plan.   

Gorilla, Orang and Chimp are quadrupeds and MUST not have a twisting section. So they have fused it in 3 creative ways.  

The only explanation is homo separated from Chimp, Gorilla and Orang while it still had the bipedal design, at least 20mya.  We share ZERO of the chimps lumbar adaptations.  We share none of the African virus load in the Miocene. 

Not a single human ancestor was in Africa between 24mya and 1.8mya.  Not one.   The great apes radiated from SE Asia as bipedal, hylobate-like creatures with a twisting lumbar section.   

-Jack


On Apr 21, 2022, at 1:52 AM, Gareth Morgan <garethmorgan@...> wrote:





From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska=odysseysailing.gr@groups.io>
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.

 

image001.png

 

"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


--
Welcome to the Aquatic Ape Theory Discussion Group


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

Gareth Morgan
 


What I am suggesting is this:

Well that seems jolly comprehensive. 

Hard to tell what's guesswork, datewise. Vernix, pruny fingers, hymen...?

Anyway, there seem to be progressively more aquatic adaptations for the first 24,800,000 years, so I'm with you so far.

Then, in just 200,000 years we turned into slim runners instead. ???

A few points...

  1. Our long, streamlined body has been frequently cited as an obvious aquatic adaptation, enabling us to dive smoothly in with scarcely a ripple, compared to the earlier lumbering Neanderthal, who apparently walked with a stoop, couldn't fully straighten his legs and would have made a dreadful splash. It also enables us to slip smoothly through the water when swimming and diving with the least turbulence and greatest energy efficiency. Hard to see how that makes us less aquatic.
  1. Every other creature can run faster than us except the tortoise. Adults almost never run, any more than they climb trees. I can't even remember how to do it. Why did we start all that pointless running around?

  2. We don't appear to have lost any of the previous aquatic adaptations in the list. Again, that is not really less aquatic in any obvious sense.

  3. Nearly all the seafood ever harvested seems to have been harvested in the last 11,000 years and there is 1000 times more of it than all the land-based food animal remains put together. Again, seems pretty aquatic to me. I don't think even agriculture reduced the amount of sea food in the diet globally -- just supplemented it.
I have more arguments about fragile bones on land and broken hips, fractured skulls from falls and so forth (not an issue in water) and I just don't get the suggestion that we forgot how to swim and dive and grew long legs for wading instead... 

Why were we doing all that wading? There's nothing to eat at wading depth unless you are pulling in nets, but you can just use longer nets and pull them in from the shallows. Paddling is good. You can get plenty of food paddling in the shallows, in streams, oyster, clam and cockle beds, and rockpools, but what would we find to eat in more than 2 feet of water that we couldn't get easier at low tide? I'm asking for suggestions here, because wading gets mentioned a lot in AAT.
 
Thanks.

G.



From: AAT@groups.io <AAT@groups.io> on behalf of fceska_gr via groups.io <f-ceska@...>
Sent: Thursday, April 21, 2022 2:26 PM
To: AAT@groups.io <AAT@groups.io>
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?
 

G: 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. 

 

Not exactly, no. What I am suggesting is this:

 

25 Ma – 11 Ma (Great apes LCA)
Orthograde aquarboreal apes / postural bipedalism (wading)
Some loss of fur (fur loss in an ancestor of chimpanzees-humans relative to macaques)

Some tendency to store fat (loss of uricase 15 Ma)

Some eccrine gland proliferation compared to apocrine glands (2:98 in monkeys, 50-50 in apes, 98:2 in Homo)

Basic tool use

 

So c. 11 Ma our ancestor was a posturally bipedal, aquarboreal, wading hominid, partially furless and possibly a little fat, had a reduced sense of smell, and possibly sweated a little to cool down. They lived in trees by night and waded in lakes, swamps and flooded forests by day, consuming AVH, cattails, etc. They may have occasionally used tools to smash open nuts, etc. They had a long flexible back, weight bearing leg bones, grasping hands and feet. They were a bit smaller than chimpanzees. (E.g: Danuvius guggenmosi, Rudapithecus hungaricus)

 

11 – 7 Ma (Gorilla LCA)

Terrestrial bipedalism (wading)

Adducted halluces

Larger overall body size

Thicker tooth enamel

By this time, our ancestor had moved away from the trees and was occupying a more open, river valley, swamp-savannah mosaic environment. They probably still slept in trees by night but their diet was almost exclusively aquatic vegetation so they spent most of their time foraging in water. Some of them may have started to exploit coastal habitats. (E.g. Ouranopithecus macedonensis, Graecopithecus freybergi).

 

6 - 5.3 Ma (LCA)

Fully bipedal

Semi-naked

Some subcutaneous fat (more in females)

Some head hair

Adducted halluces / plantigrade feet / distinct ball and narrow heel

Hymen

Descended larynx

Eccrine proliferation +

Face to face copulation

Smaller canines

Tool use

Brain: 350 – 400 cc

They were able to swim and dive quite comfortably in shallow water (like macaques), forage underwater, use stone tools to smash crabs. (I imagine something that looked a bit like the naked bonobo image I shared yesterday)

24 chromosomes

 

5.3 – 2.6 Ma

This is when Pan and Homo diverge and lots of changes happen to the two lineages.

Pan’s ancestor gradually becomes more arboreal over time, regains her fur, smaller back (fewer lumbar vertebra), halluces become abducted, develops knuckle-walking and splits into chimps / bonobos about 1 Ma. More changes in chimp than in Bonobo due to high competition among males, whereas bonobos remain more matriarchal, less competitive).

 

Homo’s ancestor gains or improves the following features:

Total loss of fur, fully bipedal on land, streamlined in the sea, hooded nose, fatter bodies,

Reduced olfaction / loss of oestrus / menopause

Matriarchal groups, individual males

Brain size from 350 cc – 650 cc (including development of areas associated with vision and manual dexterity)

Multi-pyramidal kidneys

Eccrine proliferation+++ / apocrine - - -

Long head hair

Spleen enlargement

Tool use development

Wrinkly fingers and toes

Heavier bones

Lung capacity increase
Spleen enlargement

Vernix
Swimming / floating babies

Vocal communication development (not speech)

Tears

23 chromosomes

 

2.6 Ma -  1.0 Ma (Early Homo)

Flatter, heavier skull-caps

Brain size from 650 cc – 1250 cc

Larger eyes & nostrils

Singing, possibly vocal structural communications (not quite speech)
Culture, art, architecture
Tool technology advance

Aural exostoses

Pair-bonding

 

Later Homo, e.g. Neanderthals
Brain size from 1250 – 1650 cc

Shoulder thrusting

Larger eyes, lungs, nostrils

Basic language skills

Good tool skills

Aural exostoses ++

Cranial damage

Tooth damage

 

Homo sapiens
More gracile, longer thinner bones (wading vs diving)

Shoulder throwing
Better bipedalism, running
Language
Brain reduction

Patriarchal societies

 

So, yes, our aquatic features cover many stages, many millennia. They didn’t all happen at once, but our most aquatic single phase was during the Pliocene, and it remained high throughout the Pleistocene, and finally started to dip when our species came on the scene.

 

I’ve run out of time now and have to go but may come back to other points later!

 

Francesca

 

From: AAT@groups.io <AAT@groups.io> On Behalf Of Gareth Morgan
Sent: Wednesday, April 20, 2022 11:29 PM
To: AAT@groups.io
Subject: Re: [AAT] Homo erectus (sensu stricto) the most aquatically adapted hominin?

 

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?

Bernard Harper
 

If AAT was not grouped with Lamarck or the Bible, what clever connections they could Fan et al make with more unconstrained horizons? I suspect most biologists would be quite happy for all of our ancestors after the LCA were grouped under Homo. But that would deny the naming rights to the bone-diggers, and we just can't have that. So it is still wishful thinking that our chromosomes can group all our ancestors together and clearly separate us from Pan. But I will keep looking. 

B

 

 


Bipedalism in humans

 

Bernard,
Bipdelism is the natural state of the stem great apes, (all great apes were bipedal, only homo retained it).

 Bipedalism was and is the natural result of the swinging motion of the Hylobates, which have never been in Africa.   How do they swing?  Feet raised forward, motionless, as the shoulder swing side to side. The lumbar section needed to twist, the tail is actually a disadvantage and hence was lost.  This required a new and still unique feature of the mammalian 5 section backbone, the lower lumbar twisting section.  It allows the Hylobates to travel 50kmh in the trees.

On the ground, running or walking Hylobates do the opposite…Holding arms and shoulders still while the hips swing side to side.  The biomechanics of their bodyplan allows them to do nothing else. Bipedal on the ground, legs motionless in the air. 

Humans also have the twisting lumbar section and it affects everything we do. freestyle in swimming, the golf swing, baseball pitching, all have shoulders turning independently of the hips.  

On the other hand Kicking a soccer ball, bipedal running and dancing all require the opposite, turning hips while maintaining the shoulders.   We are highly improved versions of the hylobate body plan.   

Gorilla, Orang and Chimp are quadrupeds and MUST not have a twisting section. So they have fused it in 3 creative ways.  

The only explanation is homo separated from Chimp, Gorilla and Orang while it still had the bipedal design, at least 20mya.  We share ZERO of the chimps lumbar adaptations.  We share none of the African virus load in the Miocene. 

Not a single human ancestor was in Africa between 24mya and 1.8mya.  Not one.   The great apes radiated from SE Asia as bipedal, hylobate-like creatures with a twisting lumbar section.   

-Jack


On Apr 21, 2022, at 1:52 AM, Gareth Morgan <garethmorgan@...> wrote:





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.

 

image001.png

 

"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


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