1) water mass exchange was reduced by ~90 % in a 1st step  at c 20 Ma.

(I suspect this is when the ancestor of gibbons migrated to Asia from Africa)

2) The terminal closure then coincided with the  sea-level drop caused by the onset of permanent glaciation of Antarctica at c 13.8 Ma.

(This is probably when African hominoids entered Eurasia, with Pongo going East and Dryopiths going West. But, there were signs of apes in Germany also at 16 Ma, but there was also a land bridge, Gomphotherium, c. 18-19 Ma when there was a large faunal exchange.)

https://www.sciencedirect.com/science/article/abs/pii/S0044523107000186?via%3Dihub

F.

Two-step closure of the Miocene Indian Ocean Gateway to the Mediterranean
Or M Bialik cs 2019 Scientific Reports 9, 8842

The  Tethys Ocean was compartmentalized into the Med.Sea &  Indian Ocean during the early-Miocene,
yet the exact nature & timing  of this disconnection are not well understood.

Here we present 2 new neodymium isotope records from isolated carbonate platforms on both  sides of the closing seaway - Malta (outcrop sampling) & the Maldives  (IODP Site U1468) - to constrain the evolution of past water mass  exchange between the present day Med.Sea & Ind.Ocean via  the Mesopotamian Seaway.
Combining these data with box modeling results  indicates:
water mass exchange was reduced by ~90 % in a 1st step  at c 20 Ma.
The terminal closure then coincided with the  sea-level drop caused by the onset of permanent glaciation of Antarctica at c 13.8 Ma.
The termination of meridional water mass  exchange through the Tethyan Seaway
- resulted in a global reorganization  of currents,
- paved the way to the development of upwelling in the  Arabian Sea,
- possibly led to a strengthening of S.Asian Monsoon.

See illustration:
if the Mesop.Seaway closed before the Red Sea opened, this caused the hominid/pongid split = Med.Sea/Ind.Ocean.
First, pongids colonized the Ind.Ocean coasts,
only after the Red Sea opened, hominids colonized E.African coasts.

______

There is no biological Europe. Hominins and great apes did not know about geological boundaries, or predict political futures. There was free gene flow with Europe and Asia, and less so with Africa. Early there was a lot of gene flow with Africa for great apes.
While Lufengpithecus is known only from Asia, Thailand Lufengpithecus is known in a flora which was sporead from Africa to Thai with no breaks. Which can explain why Lufengpithecus internal nasal morphology is shared with African great apes and not other Asiatic great apes or hominins.


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From: fceska_gr via groups.ioSent: Thursday, November 11, 2021 10:20 AMTo: AAT@...: Re: [AAT] I have questions. 98% eccrine in humans, vs. 2% monkeys, 52% in G/P


Marc,
Europe was the "Planet of the Apes" between 14 - 10 Ma. There are almost no traces of apes in Africa between 14-7 Ma, although one or two clearly hung on. Meanwhile great apes diversified massively in Europe, up until the Vallesian crisis, about 11-10 Ma, when grasslands and seasonal forests replaced tropical humid forests. It was cooler and drier and a lot of savannah fauna migrated into Europe. Most 'great ape' features can be found in those European dryopiths. After that, they started to disappear. The H/P/G common ancestor must have been in Europe at that time. It’s very unlikely to have been Africa and there’s no fossil evidence from the African Tethys coasts and only one or two teeth from elsewhere.
Then, at around 10-9 Ma, you find two sister taxon with close morphological similarities: Ouranopithecus in Greece/Turkey and Nakalipithecus in Kenya. Both have similarities with gorilla, and that’s about the time gorilla is estimated to have diverged. The Vallesian would have caused sea-levels to drop again and formed land bridges back to Africa. Also, there are striking similarities between the dental morphology of Ouranopithecus and Australopithecus afarensis, causing de Bonis to exclaim that if they had both been found in Africa, nobody would dispute that they were related. It could be that a close relative of Ouranopithecus migrated south, following the Nile / rift valley, eventually leading to (Orrorin / Ardipithecus) and later, A. afarensis, which by that time lived in the flooded Afar region and was a habitual wader.
My hypothesis is that G/PH was in Europe. G split first during the Vallesian and returned to Africa, perhaps via the Red Sea, perhaps via Iberia, perhaps via the Libyan deltas or Nile valleys. P/H survived in Europe as a bipedal wading ape, around the lakes and rivers and swamps, and a bunch of them got stranded on Crete c.10 Ma when the island began to separate from the Greek mainland. Over the next 4 million years, they became more coastally adapted, shallow diving for shellfish, (like macaques do). They left their footprints there, 6 million years ago, just before the Med started to dry up and the whole sea evaporated. During the MSC, the LCA (I don't know if it was Trachilos, or another taxon from Europe, eg. Graecopithecus or similar) followed the Anatolian coastline to Arabia. Then the Zanclean flood happened at 5.3 Ma and some of them made it to Africa and some of them didn’t. Those that didn’t, probably only a few thousand individuals, had to adapt to living on the Red Sea coast for the next few million years, before emerging as Homo at the beginning of the Pleistocene. (I wouldn't be surprised if some elephant ancestors got stranded there with them, becoming more aquatic at the same time we did, eventually maybe being used by early Homo (erectus) to help them cross seas, etc. during Pleistocene migrations. Meanwhile, Pan carried on along East African coastal forests and into South Africa, becoming more arboreal over time and, like Gorilla, developing knuckle-walking and regrowing their fur.
F.
On 11/11/2021 6:23 μ.μ., Marc Verhaegen wrote:


Were all Miocene Tethys-Sea-coasts (+ islands) full of aquarboreal hominids?

They were all very comparable + had comparable innovations.
How much the different branches & spp dived?waded?climbed, I don't know.

1994 Hum.Evol.9:121-139
"Australopithecines: Ancestors of the African Apes?" &
1996 Hum.Evol.11:35-41
"Morphological distance between australopithecine, human and ape skulls"
show:
1) E.Afr.apiths (Lucy cs) were closer relatives of G than of HP:
apparently G followed the incipient Rift:
-> Pliocene gracile afarensis -> Pleist.robust boisei.
2) S.Afr.piths were closer relatives of P than of H or G:
Early-Pleist.Homo is found at Java.
I think your hypothesis that the Red Sea-opening c 5 Ma caused the H/P split (W/E) is correct.
Apparently P followed the E.Afr.coasts (parallele evolution of P//G):
-> Pliocene gracile africanus -> Pleist.robust robustus.

IOW, hominids c 8 Ma in the Med were close relatives of HPG,
they looked very much like the HPG-LCA (+-the same lifestyle),
but were not our direct ancestors IMO:
IMO, the HP/G LCA c 8 Ma (HP/G split) lived in the Red Sea.

Whether Homo after the H/P split c 5 Ma lived for some time on an island (Danakil??) I don't know.
I'd think, Pliocene Homo after the Red Sea opening c 5 Ma simply followed the Ind.Ocean coasts.




------ Origineel bericht ------Van: f-ceska=odysseysailing.gr@...: AAT@...: donderdag 11 november 2021 15:56Onderwerp: Re: [AAT] I have questions. 98% eccrine in humans, vs. 2% monkeys, 52% in G/P
But might Pan or the H/P LCA also have spent a lot of time diving during certain phases?? Red Sea? E.Afr.coasts?
I have little doubt. But LCA probably in the southern Med / Crete, prior to MSC. Then Pan: E. African CoastsHomo: Red Sea
F.
On 11/11/2021 4:42 μ.μ., Marc Verhaegen wrote:

(sorry for this late reply - busy period - covid...) Yes, thanks a lot, Francesca, for your text (while reading, I shortened it a bit), needless to say, I largely agree. It's becoming clear IMO - early-Pleist.Homo was +-full-time a slow & shallow diver (mostly for shellfish?) along the Ind.Ocean etc., - late-Pleist.Homo waded a lot, possibly seasonally inland along rivers? connection with (inter)glacials? But might Pan or the H/P LCA also have spent a lot of time diving during certain phases?? Red Sea? E.Afr.coasts? I think you might find this paper interesting, but the researchers compared humans, chimpanzees & macaques. I don't know about hylobates or gorilla unfortunately (it would be good to know). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6289065/ Cetacea & Sirenia have lost their apocrine glands: because they have no use for them (scent-signalling, sweating). Aquatic mammals do not need to sweat: being in the water is how they keep cool, and they have plenty of blubber. Even animals descended from a semi-aquatic ancestor have lost their apocrine glands, e.g. hippos, rhinos & pigs - water buffalo have only 10 % as many as domestic cattle. Instead of apocrines, Pinnipedia, lutrinae, castoridae & humans have extensive eccrines & SQ-rich sebum for waterproofing. These glands, on most animals, tend to appear in a few limited locations on the body, they produce a clear, colourless, rel.odourless fluid: mostly water & salt. In arboreal primates, eccrines are found on the hands & feet: for grasping branches without slipping? Chimps & gorillas have eccrine glands & ridges on their knuckles: to protect their knuckles? Over the course of primate evolution, some eccrines have spread from the palms & soles to other places on the body. African apes have by far the most eccrines, slightly more than apocrines (52 to 48 %). But humans have 99 % eccrines (2-5 M) vs 1 % of apocrines. Apocrines begin to develop in the human embryo, and are present all over the body during the 5th month, but then disappear: we retain them only in our armpits, pubic area, nipples: did apocrines started to become redundant at a rel.early point in hominoid evolution? early- or mid-Miocene, when aquarboreal apes had less need for scent signalling? OTOH, eccrines begin to appear on the foetus’ palms & soles during the 4th month, but then begin to develop rapidly all over their bodies during the 6th month. Scientists have not been able to find evidence of any correlation between eccrine & hair-follicle density, but instead have noted: “hair follicle specification occurs prior to the onset of eccrine gland formation during human gestation.” [i]: was the development of eccrines all over our bodies a rel.recent modification, shortly after we started to lose our fur? It is generally accepted that the main purpose for the large proliferation of human eccrines is for sweat cooling, although no other primate uses them for this purpose. Eccrine sweat consists of mainly water, Na & Cl, but also contains a mixture of other chemicals originating from the interstitial fluid & the gland itself. While sweat can help in body cooling, it is typically produced in much greater excess than needed, leading to a risk of dehydration, and there is no inbuilt mechanism that seems to regulate this. With gentle sweating, much Na is re-absorbed by the body, but as sweating increases, the Na that is reabsorbed declines, leading to dangerous depletion levels & possible death in just a few hours. There is no evidence that eccrines exist to remove toxins, as was once believed. [ii] The production of eccrines also seems to vary: children in hot, water-stressed areas develop more than those who live in cool or water-plentiful environments. [iii] Unlike other animals, modern humans do use eccrine glands for sweat cooling, a very effective exaptation when there is no water scarcity: we can quickly replace the water & salts we have lost. But it’s also highly inefficient: 1) it’s slow to start, taking up to 20 minutes to kick in, sometimes resulting in heat-stroke, 2) it wastes water, sometimes leading to dehydration & death if the water cannot be replaced quickly, 3) it wastes salt which can also lead to death in just 3 hours, 4) dehydration causes platelet increase, which can lead to thrombosis & death. It seems clear therefore that using the eccrine glands for sweat cooling is extremely inefficient in areas which are far from fresh water & sources of Na (African savannah): why is the human body covered in eccrine glands? what happened to our apocrines? The only other mammal that appears to sweat as abundantly as humans are fur-seals when they are on land. [iv] Their very thick layer of blubber keeps them warm in the sea, but can also cause them to overheat ashore: almost any activity on land causes them to pant, raise their hind-flipper (abundantly supplied with eccrine glands) and wave them about.[v] But what if sweat cooling was not the primary reason why the human body is covered in eccrines? Did evolution re-assign the function of our eccrine glands, and distributed them all over our body for maintaining water/salt homeostasis while in a marine environment? If we were able to absorb water from the sea, but not the salt, this would have helped our ancestors to survive when there was little or no access to a reliable supply of fresh water. Humans have at least 5 copies of a gene called Aquaporin 7 (AQP7, a human lineage-specific (HLS) gene), thought to play a role in water- & glycerol-transport -across membranes via the eccrine glands. [vi] In comparison, chimps & other apes have only 1-3 copies. It appears in one of the most evolutionary dynamic regions of the human genome, chromosome 9, the location of the greatest concentration of gene copy number increases: did the change in eccrine function come about shortly after our divergence?[vii] But if our ancestors were spending all day in the sea, why would they need a vast proliferation of eccrines for the purpose of sweat cooling? [i] Kamberov YG, Guhan SM, DeMarchis A, et al. Comparative evidence for the independent evolution of hair and sweat gland traits in primates. J Hum.Evol. 2018;125:99-105 doi 10.1016/j.jhevol.2018.10.008 [ii] Baker LB. Physiology of sweat gland function: The roles of sweating and sweat composition in human health. Temperature (Austin). 2019;6(3):211-259. Published 2019 Jul 17 doi 10.1080/23328940.2019.1632145 [iii] Rosinger, Ashley Y., Biobehavioral variation in human water needs: How adaptations, early life environments, and the life course affect water body homeostasis. October 2019 American Journal of Human Biology https://doi.org/10.1002/ajhb.2333 [iv] Rotherham LS, van der Merwe M, Bester MN, Oosthuizen WH (2005) Morphology and distribution of sweat glands in the Cape fur seal, Arctocephalus pusillus pusillus (Carnivora : Otariidae). Australian Journal of Zoology 53, 295-300. https://doi.org/10.1071/ZO04075 [v] [WN McFarland cs 1979 "Vertebrate life" Collier p.773] [vi] Preston GM, Carroll TP, Guggino WB, Agre P. Appearance of water channels in Xenopus oocytes expressing red cell CHIP28 protein. Science. 1992 Apr.17;256(5055):385-7. doi: 10.1126/science.256.5055.385. PMID 1373524. [vii] Dumas L, Kim YH, Karimpour-Fard A, Cox M, Hopkins J, Pollack JR, Sikela JM. Gene copy number variation spanning 60 million years of human and primate evolution. Genome Res. 2007 Sep;17(9):1266-77. doi 10.1101/gr.6557307. Epub 2007 Jul.31. PMID: 17666543; PMCID: PMC1950895. ______ Jack D.Barnes: I have Questions on the: 48 % apocrine / 52 % eccrine in chimp/gorilla, vs 2 % eccrine in monkeys, and 98 % in humans. I remember looking prior to doing the submersion testing with Gareth last year. But never found anything. 1. Does anyone know eccrine % in Hylobates and Orang? 2. Since Gorilla & Chimp occupy the same basic geographic erritory (within 10° of equator), could our 2 % be explained constant water immersion? Could it be also a cold weather adaptation? 3. Is it eccrine Amplification in humans (we have 100x the eccrine of chimp/gorilla) that causes the difference for 48/52 % to 2%/98% in humans? Just sheer numbers of eccrine? We have same number of Apocrine? _____ On Nov 8, 2021, at 4:01 AM, fceska_gr wrote: mv: If male chimps also have male pattern alopecia, this could imply their ancestors also regularly dived?? Chimps sometimes also use stone tool, cf sea-otters. If so,(??) this was Pliocene? or already late-Miocene?? still in the Red Sea? &/or along the Indian Ocean coasts of E.Africa?? Yes, I believe so. 1. Eccrine gland distribution & proliferation increased dramatically in the ancestors of all great apes (48 % apocrine / 52 % eccrine in chimp/gorilla, vs 2 % eccrine in monkeys, and 98% eccrine in humans), so possibly mid-Miocene, suggesting the ancestor of great apes was already aquarboreal. This happens after hair follicle specification appears on human / chimp fetus: were all early hominids were already partially furless since the mid-Miocene, living in Tps 8-9° higher than today, in tropical gallery forests with far greater humidity & many more bodies of water all over Europe than today.? (Fur would have been more a hindrance than a help.) 2. Graecopithecus had very similar dental morphology to Homo, 7.2 Ma. (IMO, certain Homo characters were already present in the LCA of Pan/Homo): bipedalism, furlessness, eccrine gland proliferation, possibly tool use, similar diet, possibly already shallow diving? 3. Very human looking footprints on Crete, 6.0 Ma. (Crete separated from the Greek mainland between 10 - 12 Ma, then rejoined during MSC 5.9 - 5.3 Ma.) Was this the LCA? Was this Homo after the split? Was this Pan after the split? They may have gone extinct without descendants, or they may have migrated south from the Med during the MSC. 4. Zanclean flood 5.3 Ma cut off the route into Africa at the top of the Red Sea after most of Africa's extant savannah fauna had migrated there from Eurasia (incl. African great ape ancestors). 5. Some early African hominids (i.e. Lucy) were already more bipedal, later spp were less bipedal. Evidence of knuckle-walking appears late in the fossil record. 5. Early Homo (radically different from apiths still existing at the same period) appeared 2.4. - 2.0 Ma in various locations (China, Africa). Genetic analysis tells us that they emerged from an ancestral population of between 10,000 - 100,000 individuals that had survived in an isolated niche, outside of Africa ("somewhere the size of Rhode island") where they lived in a unique environment prior to 2.0 Ma and for >1 My (long-necked bottle). Criteria: - Outside of Africa (retroviral evidence suggests Homo ancestors were not in Africa 3-4 Ma). - Ancestral population lived in isolated niche the size of Rhode island (i.e. 3000 km2) for at least 1 My according to genetic evidence. - Coastal zone, no forests, no arboreal adaptations (as per unique human semi-aquatic adaptations). - No possibility of migration /introgression for at least 1 My according to genetic evidence. - Must have high diversity of aquatic foods all year round to survive for at least 1 My. - Should be centrally located between Africa & E.Asia, to explain migration of Homo after 2 Ma. - Dates: Pliocene (between 5.3 - 2.6 Ma). Mean estimates for LCA divergence according to diverse sources: 5.3-5.6 Ma. Appearance of early Homo only after 2.6 Ma (end-Pliocene / global cooling, sea-level decline at onset of- Pleistocene). Only one place matches the criteria: the Red Sea - Eastern coast, outside of Africa - c 2000 km in length - the Zanclean flood via the Med cut off the northern route into Africa, 5.3 Ma. Water overflowed the Red Sea, raising water-levels by up to 100 m,and possibly filled the entire Afar valley region. The Eastern coast would have been cut off, N, S, Z & W. No possibility of migration / interbreeding. - There was a period of hyper-aridity in Arabia between 5.3 - 3.3 Ma, making it impassable for all spp. - Has 1000s spp of clams, seaweeds, shellfish, USOs, shallow reef sessile foods, birds eggs, turtles, etc. - gateway between Africa & Eurasia - dates match Francesca ______ https://imgshare.io/image/verhaegen1985.NnU1uX "The sensitive response to androgen is an important feature of human hair: at puberty, hair grows in places where we had none, and as we age, changes in hormonal levels can lead to thinning hair in both men & women, and to baldness in some. But humans are not the only animals to experience this. It happens in chimps & stump-tailed macaques in nearly the same way.(??--mv) And mice, rats, hamsters, rabbits & sheep became sensitive to fur loss, when their androgen levels were manipulated in the laboratory. There was even a report in which wattled starlings in the wild displayed a bald scalp in response to natural changes in androgen levels." IMO (1987 Med.Hypoth.24:293-9 "The aquatic ape theory and some common diseases"), the hair distribution in men was adapted to our diving lifestyle: beard+moustache, baldness, shorter neck-hairs than in women, pubic hair + sebaceous gland distribution? & in women after menopauze?? Adult women grow longer head hairs (& less sebaceous glands) that can float at the water surface: for the baby to grasp, as Elaine thought? If male chimps also have male pattern alopecia, this could imply their ancestors also regularly dived?? Chimps sometimes also use stone tool, cf sea-otters. If so,(??) this was Pliocene? or already late-Miocene?? still in the Red Sea? &/or along the Indian Ocean coasts of E.Africa??
-- Francesca Mansfield Odyssey Sailing Tel: 0030 24280 94128 Mobile/WhatsAp: +30 6974 659 156 f-ceska@...



-- Francesca Mansfield Odyssey Sailing Tel: 0030 24280 94128 Mobile/WhatsAp: +30 6974 659 156 f-ceska@...