Regular readers will know that I am an unashamed fan of non-standard theories, aka fringe theories or whacky theories, and of course we looked just recently at the haematotherm theory. Doubtless you've all heard of the aquatic ape hypothesis (AAH): that strangely popular notion which promotes the idea that modern humans owe their distinctive features to a marine phase. While it still seems conceivable that at least some fossil hominins foraged on shores and in mangroves, all of the evidence so far put forward to document our aquatic heritage is demonstrably incorrect and fails to fit the evidence as well as the idea that we originated in woodlands and grasslands. Anyway, while the AAH might be well known, have you heard about its most radical variation: the theory of initial bipedalism? According to this little known school of thought, not only do humans owe their anatomy to a direct aquatic ancestry, so do ALL mammals and all other tetrapods. In fact, all vertebrates evolved from aquatic bipedal human-like ancestors like the marine homonculus shown here [reconstruction by Robert Dumont]...
Initial bipedalism is not a new idea, but was first mooted in the 1920s by a group of European mammalogists, most notably Serge Frechkop and Max Westenhöfer. Curiously, it has become best known via the writings of zoologists who are well known for their active participation in cryptozoology: it is in fact obliquely referred to in Bernard Heuvelmans's On the Track of Unknown Animals (p. 171 of the 1995 edition), is discussed further in Heuvelmans & Porchnev's (1974) volume on the modern-day survival of neanderthals, and was discussed at length by Heuvelmans (1954) [oh, if you don't know who Bernard Heuvelmans is, go here].
Indeed, what makes initial bipedalism all the more appealing and/or bizarre is the fact that its proponents have incorporated cryptids, like yetis and relict neanderthals, into their writings on it (e.g. de Sarre 1995, 1996). More on this in a moment. Needless to say, it has very much remained firmly in the 'grey literature' and - to my knowledge - has never garnered any mainstream support. Today, its only advocate (to my knowledge) is French ichthyologist Francois de Sarre [shown in adjacent image]: he not only publishes articles on the subject, but also runs the Centre d'Etudes et de Recherches sur la Bipedie Initiale (CERBI). A serial publication, dubbed Bipedia, was formerly published by the CERBI, and I think still is. Bipedia is, as you'd guess, mostly filled with articles on initial bipedalism, but it has also contained articles on other aspects of arcane zoology: my favourite are those on Homo alaouite, a new species from Devonian rocks of Morocco, named for a hominid skull about 61 mm tall. According to its describer, H. alaouite indicates either that we descend directly from a hominid ancestor who was about 40 cm tall, or that tiny little humans like this still live among us. Ok.
At the root of the initial bipedalism theory we have Westenhöfer's argument that, while mammals had their roots in amphibious quadrupeds, humans are the most structurally primitive of all the primates, that apes are descended from human-like forms, and that the unusual features of the human body evolved for life in water (e.g. Westenhöfer 1935). De Sarre (1992, 1997) has reported that he first began to consider the broader question of tetrapod origins after deciding that fishes might not be the aquatic ancestors of tetrapods, but rather that said fishes may just as well be the aquatic descendants of terrestrial tetrapods. So in its extreme, current incarnation, it seems that, to be an 'initial bipedalist', you have to reject the idea that humans and other tetrapods descended from fish, and accept the idea that fish are the secondarily aquatic descendants of amphibian-grade tetrapods. If tetrapods don't descend from fish, just where did they come from?
Aquatic prevertebrates and the marine homonculus stage
Beginning with an amphioxus-like aquatic 'prevertebrate', it is proposed that such animals evolved a bubble-like gas-filled floating organ that helped control buoyancy [see sequence above, borrowed from Bipedia]. Here we have the origin of the big brain: it initially functioned as a sort of float that enabled these little marine creatures to float like corks at the air-water interface, their bodies suspended vertically in the water. Two pairs of limbs and a little tail evolved in these animals to help them steer themselves in the water, and by this stage they are imagined to have resembled vertically-poised floating embryos, with axolotl-like branched gills sticking out of the neck. These hypothetical creatures have been termed 'marine homonculus' [not homunculus] animals. Exactly what, if any, evidence this is all based on is not entirely clear; some fleeting mention has been made of 'meridian lines as described in the field of acupuncture', but we then move swiftly on.
Aquatic homonculus creatures then evolved endothermy and body hair, and ears apparently evolved as breathing orifices [see adjacent reconstruction, again by Robert Dumont]. Viviparity evolved at about the same time. What with its vertical posture and preadaptation to bipedality, its insulatory hair, ability to breathe air, and plucky spirit, the little marine homonculus was well suited to stage a tentative invasion of the land and it is from these little bipeds that the first human-like creatures evolved. These, so de Sarre (1997) explains, were the first vertebrates to colonise the land. They make excellent models for the first terrestrial colonizers because, unlike the small-brained lobe-finned fish of zoological orthodoxy, with their lack of intellect and clumsy bodies, they were clever little animals with a well developed sense of exploration, and with prehensile hands to boot (de Sarre 1989).
Dehumanization and reptilized humanoids
We humans have retained this primitive body shape, and in fact it is the most primitive body shape for all vertebrates: everything else has evolved from it. By straightening out the flexed skull base, modifying the vertical posture to a quadrupedal one, and specialising the forelimbs for terrestrial locomotion, it is proposed that hundreds upon hundreds of vertebrate lineages have 'dehumanized', evolving away from the humanoid condition and toward that of cows, cats, turtles, lizards and (in its most modified form) the secondarily aquatic fish (de Sarre 1988, 1989). We are literally the archetype from which all other vertebrates have arisen.
Chimps, gorillas, australopithecines and so on are still in the early stages of dehumanization, and have not gone too far from the ancestral humanoid condition. Here's where we come back to cryptozoology. Both Bernard Heuvelmans and Francois de Sarre have been active in promoting the idea that the many man-like primates of the cryptozoological literature are not only real, biologically plausible animals no more remarkable than chimps or gorillas, but also that they help shed light on the descent of dehumanized primates from human-like ancestors.
Yetis, the African kikombas and agogwes (interpreted by these authors as surviving australopithecines), and the Pakistani bar-manu (interpreted by these authors as a surviving neanderthal), are all interpreted as descendants of human-like animals very much engaged in the process of dehumanization (de Sarre 1996). It is argued that dehumanization occurs as 'The forehead recedes, the jaws are developing, the masticatory apparatus becomes mightier which induces an enlarging of the osseous crests of the skull to which the concerned muscles are linked. The whole silhouette can modify itself, the heads sinks into the shoulders, the body is more and more inclined forwards, tending to horizontality and a quadrupedal gait. All beings whose form is attained by dehumanization, not only stop acting like humans, but more and more closely resemble the image, we see, of the beast' (Heuvelmans, quoted in de Sarre 1996, p. 106) [adjacent image shows reconstructed appearance of the Minnesota iceman, interpreted by Heuvelmans and others as a surviving neanderthal, and referred to by them as Homo pongoides].
Dehumanization in action, supposedly
Supposedly, a case study from Norway illustrates dehumanization in action within our own species. I was always fascinated by this and only recently got round to tracking down the reference. The story goes that a group of mentally under-developed adolescents, growing up in humid Norwegian valleys and deprived of sunlight, grew massively prognathic jaws, enlarged teeth, and thickened body hairs. They eked out a living by grabbing and eating small mammals. The origin for this case study is Ivan T. Sanderson, who wrote of it in his 1961 book Abominable Snowman: Legend Come to Life (we looked at Sanderson previously, in the 'living pterosaurs' article). Unfortunately; (1), Sanderson does not cite a source for this story: I hope there is one, but I haven't been able to find it; and (2), there are doubts about the authenticity of some of the facts that Sanderson related in his books. In fact we know without doubt that some of the facts reported in his books were fabricated.
Compared to even the most bestial of humanoid primates, most other mammals are far more advanced, having becoming strongly modified relative to their humanoid roots. Of course, the other vertebrates are even more strongly modified relative to the ancestral erect-bodied, big-brained, bipedal body shape. Cetaceans, incidentally, are primitive and have evolved directly from marine homonculus animals without going via an intermediate terrestrial phase (de Sarre 1994). At some point in their history, various lineages have 'reptilized', evolving features that we conventionally associate with reptiles: from small humanoid bipedal forms with round skulls, groups like dinosaurs and birds have become highly specialized, with homodont dentitions set in long jaws, elongate tails and so on (de Sarre 1993).
Alas poor Haeckel
The cornerstone of initial bipedalism is of course vertebrate embryology: it relies on the fact that the globular skull and flexed skull deck of vertebrate embryos is 'the most ancient in terms of phylogenetic rapprochement, at least as far as the actual history of the vertebrates is concerned' (de Sarre 1997, p. 155). As de Sarre often states, this point of view isn't novel but originated with Louis Bolk's 'fetalization' models of the 1920s: noting that, unlike other mammals, adult humans retain the flexed skull base of embryos, Bolk proposed that adult humans are essentially upright, reproductively active embryos.
Given that embryos start out as ball-shaped masses of cells, it's difficult to understand how they might form during growth without going through stages where their heads are rounded. Furthermore, flexed skull bases aren't quite as widespread as Bolk and others thought given that we now know that Haeckel's famous drawings of stunningly similar vertebrate embryos (which are frequently reproduced in the literature on initial bipedalism) were wildly inaccurate (if not fabricated). In any case, it hardly needs saying that an overwhelming amount of anatomical, molecular and fossil data shows that round-skulled humans are highly derived, paedomorphic novelties among the vertebrates. If you're wondering, incidentally, how fossils fit into this, the answer is that they don't, because they're not very useful for this sort of thing, and can be safely ignored! I'm joking in saying this of course, but de Sarre isn't, and has said exactly this on several occasions.
And that, in essence, is the theory of initial bipedalism. The good news (I think) is that, should you want to know more, ALL of Bipedia's contents are available freely online here.
Refs - -
de Sarre, F. 1988. Initial bipedalism: an inquiry into zoological evidence. Bipedia 1, 3-16.
- . 1989. What did the first vertebrate look like that entered land? The standpoint of initial bipedalism theory. Bipedia 3, 17-20.
- . 1992. La coalacanthe a-t-il un passe terrestre? Bipedia 8, 1-5.
- . 1993. In search for taxonomy and relationships in the vertebrates, in connection with the marine homunculus hypothesis. Bipedia 10, 14-24.
- . 1994. On the origins of whales and dolphins from an archaic marine form. Bipedia 11, 1-8.
- . 1995. The mysterious hominoids of Africa in the light of modern research. Animals & Men 6, 23-25.
- . 1996. About the survival of relict hominoids from the point of view of a zoologist. In Downes, J. (ed) CFZ Yearbook 1996. CFZ (Exeter), pp. 98-111.
- . 1997. Were aquatic pre-humans the first vertebrates to enter the land? In Downes, J. (ed) The CFZ Yearbook 1997. CFZ (Exeter), pp. 142-156.
Heuvelmans, B. 1954. L'homme doit-il etre considere comme le moins specialise de mammiferes? Sciences et Avenir 85, 134-136.
- . & Porchnev, B. F. 1974. L'homme de Néanderthal est toujours vivant. Plon, Paris.
Westenhöfer, M. 1935. Das Problem der Menschwerdung. Nornen-Verlag, Berlin.
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I don't know - It seems to me that the fossil minicreatures described by Chonosuke Okamura could be informative in this regard, particularly those of the protominilorientalus stage.
Blimey!, I'm not sure 'alternative' is strong enough a word in this case. Interesting how all the alternatives to the normal case of evolution seem to regard the fossil record as an irrelevant nusiance. Interesting post :)
What an interesting take on tetrapod evolution! Just goes to show how creative biologists can be.
Though I think Tiktaalik would be insulted.
Wow, HCF -- I woulda never thunk it.
I find it interesting that any morphological sequence can be inverted, if you throw out the sequence in which the fossils appear. I'd like to find some more [derived x] Came First theories--they are very entertaining.
Wow. I've never heard of that insanity before. I'm amazed that it's persevering.
It's amusing that this theory has its roots in embryology, and yet the current sate of embryology, and more specifically evo-devo, are some of the best means of bebunking this (which would be, let's be honest, like shooting fish in a barrel).
Someone should confirm if de Sarre likes mudkips. An appropriate way to approach this would be: "So I heard you like mudkips?"
Aha! Now I see where Leprechans come from. BTW - This also becomes much more clear when you are on your second bottle of Jameson's.
Wow! What was it, and can I get it legally in Netherlands?
Just as a matter of semantic nit-picking, may I suggest that you might have been over-indulging in exposure to corporate news media: "radical" is not a synonym for "crazy"...
The Norwegian story sounds fabricated. Painfully obviously so.
Has de Sarre ever bothered to explain how and why the gas bubble got filled with nerve tissue? (Insert joke that it never has, at least not in some of our contemporaries...)
Check out Aaron Filler's The Upright Ape. He didn't convince me, and I think he also has misconceptions about other evolutionary issues (he appears to be a huge proponent of the view that mammals drove dinosaurs to extinction), but it's a good one to read if you like to stay informed about alternative ideas!
And de Sarre doesn't even limit himself to biology. He has also written a book about how all of history is fake and the Middle Ages never happened, and the latest Bipedia contains an article by some guy who thinks that the Voynich manuscript (an apparently medieval manuscript in an undeciphered script, possibly fake) is about alien spaceships.
Speaking of bizarre phylogenies, have you seen those by Gustav Steinmann (first quarter of the 20th century)? Xenarthrans evolving from ornithischians, whales from plesiosaurs, ichthyosaurs and mosasaurs, walruses from dinocerates, primates from dinocephalians, ascidians from rudists, cacti from sigillariae...
Finally it all makes sense!
This explains the end of 2001 a Space Oydessey!...
So this theory would make what Grey aliens living fossils than?
This may be the most interesting post you've ever written, Darren! My eyes kept getting wider the whole time I read it!
It appears that the Bipedia archive is in numerous non-English languages, but I read a comment (from a letter, apparently) claiming "initial levitation" is better than "initial bipedalism", in part, if I understand it, because we often have dreams of levitation/flying, which is our "soul" recalling an ancient truth (or something - my mind was in shock that people believe this and couldn't quite figure out what he was saying - I need to go back and try to read it again). Definitely a Wow! moment. Thanks for bringing this up.
At the risk of being one of those annoying nit-pickers, I think you can hardly call these "theories." Hypotheses would be much more appropriate.
This kind of thing makes Stuart Pivar look almost respectable. Personally my favourite fringe theory is William Patten's idea that vertebrates evolved from eurypterids.
You know, that hypothesis makes a lot of sense...
Its only weakness, as far as I can tell, is its obligate reliance on plucky spirit.
Otherwise, extremely plausible.
Let me guess: He also asserts that the whole terrestrial evolutionary process (thus far) happened much faster than any mainstreamer admits. Right?
If they evolved a way to fill the skull with hydrogen, the buoyancy in air would have helped them achieve upright terrestriality.
The swimming monkey reminds me of something out of "After Man."
Yet another moron believing everyone dreams about the same things. I never dream I'm levitating or flying. Falling yes, but not flying. With one or two exceptions -- I realized I was dreaming and then decided I might just as well take off.
Individual variation is generally misundreshtmated. I have noticed that the nails on my ring fingers grow noticeably faster than all others. I wondered if that had to do with our very distant ancestry (like, Middle Permian and earlier), when the ring finger was the longest. Then I read a matter-of-fact statement that the nails on the middle fingers grow fastest...
It's possibly big enough to count as a theory, but given the massive amount of tests it has already failed, hmmmm...
Wasn't that fairly mainstream in the late 19th and/or early 20th century or so, among paleontologists at least?
This was a damned good post, even by this blog's high standards.
[quote]Someone should confirm if de Sarre likes mudkips. An appropriate way to approach this would be: "So I heard you like mudkips?"[/quote]
So not only are reptiles derived from humanoids, but the various reptile groups are independently "reptilized"? Are they trying to make their scenario as non-parsimonious as possible or what?
Well, here is another wacky reference:
Jos Verhulst "Developmental Dynamics"
I'm the author.
Patten's theory was somewhat unorthodox, most people who actually worked on fishes were quite happy with Cope's classification of Ostracoderms as agnathans, though some still followed Agassiz' general system.
Patten actually thought he'd found evidence of limbs and jaws in Tremataspis. He also thought that instead of turning over as Geoffroy St Hilaire's earlier model proposed the agnathans evolved an entirely new mouth, and the eurypterid one atrophied.
Maximum munificence reached at last!!! <champagne>
Judging from that website, you have reinvented the concepts of paedomorphosis and peramorphosis without noticing that these terms exist, you or at least your reviewers sell ideas as new that aren't new (like vertebrates being larval urochordates that never grow up*), and you add some metaphysics that looks untestable and superfluous to me, like us somehow being the goal of evolution. (Why not our head lice, whom to feed is our almost obvious purpose? Or why not any of the beetles -- forget the beetles, why not any of the bacterial diversity out there?)
* That one is probably wrong, BTW, because the urochordates and the vertebrates are apparently more closely related to each other than to the cephalochordates. It looks like the urochordates added the sessile stage to their ontogeny instead of the vertebrates subtracting it. Phylogenetic hypotheses can test scenarios, not the other way around.
So everything, especially humans, evolved from airheads. Finally, things are starting to make sense.
For those of you who read Spanish, here's another really fun one.
[from Darren: sorry for delay, message got held up by publishing platform]
Regarding the marine homonculus pic at the top of the post... I've encountered people exactly like this in a remote village in North Yorkshire; they inhabit the local pub and rarely venture outside except under the cover of darkness to hunt for cheesy snacks at the corner shop.
Wow! This is creative genius at its best. Can we also say that ammonites, natuloids and all other cephalopods evolved from such "buoy-men" that grew tentacles on their lips and spiraling, calciferous plates on their heads?
At least, it would explain the presence of Cthulhu as an intermediary form - another mystery finally solved!
Intermediate nothing! Cthulhu bred Men deliberately as a food source. Any assumption of accidental development is fatal to progress of understanding.
What have we seen that is reminiscent of this "theory of devolution"? Almost a year ago you mentioned a theory according to which certain organisms, often thought of as fairly basal invertebrates, are actually deeply embedded in crown-group Mammalia: to wit, that Turbellarian flatworms are derived from a Rhinotalpa-like Rhinogradentian!
Oh My! this was an amazing post. With some trepidation I checked to make sure it was not April 1.
BTW these days molecular evolutionists present evidence that urochordates are closer to vertebrates than is amphioxus: (amphioxus (urochordates,vertebrates)). It was surprising to me but it looks as though there is not much going against it in terms of protein trees. Even worse the xenoturbellids are deep within metazoa inside deuterostomes. Yet they are amongst the most disrespectable metazoans you will see. Strange indeed can be the evolutionary trajectories of animals!
This was a damned good post, even by this blog's high standards.
[quote]Someone should confirm if de Sarre likes mudkips. An appropriate way to approach this would be: "So I heard you like mudkips?"[/quote]
Lurk moar. Sage goes in the email field.
Also, [quote] does not work for comment formatting. If you'd previewed your post before posting, you'd have realized this.
Amazing really. Air heads? On the savanna? Sacre bleu!
1) You write: "... you've all heard of the aquatic ape hypothesis (AAH): that strangely popular notion which promotes the idea that modern humans owe their distinctive features to a marine phase." This shows a few prejudices: "strangely popular"; "their" instead of "some of their"; "marine" instead of "waterside".
2) Then you write: "While it still seems conceivable that at least some fossil hominins foraged on shores and in mangroves ..." AAH is not about "some fossil hominins" (of uncertain connection to our ancestral line), but about human ancestors.
3) Then: "... all of the evidence so far put forward to document our aquatic heritage is demonstrably incorrect ..." This is wrong: all so-called objections (John Langdon etc.) are ill-informed and/or out-dated, eg, google "aquarboreal".
4) Then: "... and fails to fit the evidence as well as the idea that we originated in woodlands and grasslands." Idem. The once popular savanna story is no longer followed by leading paleo-anthropologists, eg, Stringer, Wood, Wrangham, Groves etc. Prof.Tobias: "If ever our earliest ancestors were savannah dwellers, we must have been the worst, the most profligate urinators there..."
Hi Marc. I am familiar with your articles and the aquarboreal hypothesis. Saying (as I did) that some fossil hominins might have foraged on shores and in mangroves is not the same as supporting the AAH. Thanks for commenting - I have actually been planning for a while to write about the aquarboreal hypothesis (partly because of sloths).
Well, it looks like we came out of "woodland" and into outright savanna pretty late. I bet this is how all those "leading paleoanthropologists" see it.
"According to this little known school of thought, not only do humans owe their anatomy to a direct aquatic ancestry, so do ALL mammals and all other tetrapods."
The sentence (bold section only) above accurately reflects conventional current evolutionary theory. AFAIK all tetrapods do have aquatic ancestors, just like fish, butterflies, etc. Is there any indication that they didn't? Does the word 'direct' have special significance?
Maybe 'evolutionarily recent' rather than 'direct' might convey your meaning more clearly?
I support coconut woodland savannas and kelp forests!
So you understood the sentence anyway :-)
If that's what Darren meant, then yes.
[Actually, I was just testing whether bold worked in the comments section. It works! :D ]
Earlier post on marine reptiles mentioned inner and outer nostrils, I was just directed to this link on front and rear nostrils and how they evolved, regarding the development of the nose, sniffing and underwater breathing and breath-holding. I'm still trying to comprehend it, (would be easier with pictures), but seems connected.
ps. I also support paddy rice and marsh reed grasslands!
I wasn't going to mention my site here in comments, since it's not related to the Initial Bipedalism site, but since Marc Verhaegen showed up, here it is, along with the direct link to the page about Marc.
Aquatic Ape Theory: Sink or Swim?
The page on him points out the degree to which his claims can be relied on, as well as howlers such as his claim that Neadertals had snorkel noses, that mountain beavers are aquatic, and that rhinos are "predominately aquatic" and "3 of the 5 species of rhino are as aquatic as hippos are", along with others, and his making up an institutional affiliation for himself, plus his online style, which is a red flag as I mention on my site:
Online, besides his numerous insults in several languages, he commonly makes comparisons of himself and/or the AAT/H to Wegener (starting with his very first online post, after only a few days online), and he also commonly makes more offhand comparisons of himself and/or the AAT/H to Darwin, Galileo, and Einstein, as well as comparing the AAT/H theory to Copernicus').
Darren Naish is quite right to point out that "saying (as I did) that some fossil hominins might have foraged on shores and in mangroves is not the same as supporting the AAH". The attempt to claim this is a bit of goalpost shifting on the part of AAT/H proponents (also outlined on my site) that has been going on for some time, and is part of why they are so coy about naming the aquatic creatures we supposedly (but don't actually) share characteristics with.
Thanks for showing up Jim, I am a frequent visitor of your site.
What seems connected with what?
since this post relates to aquatic effects on mammals, ...
in your old blog, you discussed 2 possible origins of Baikal seals, 1) Caspian/Aral Sea to Atlantic Ocean 2) Enisei/Angara river to Arctic Ocean
Perhaps an alternative source might have been the Lena River?
Per one source, the Angara outlet from Baikal is only 35ka, caused by tectonic shifting. I speculate that previous to that, the Lena was the outlet to the Arctic. Unfortunately, I have no topo map to check the watershed topography, but the Lena begins just 7 kilometers from Lake Baikal and flows northward to its arctic delta, and the same tectonic shift that opened the Angara may have closed the Lena.
There were people living on the Aldan/Lena 33ka (Diuktai cave artifacts) who I think had arrived from Lake Baikal (which has numerous shore mineral hot springs that would sustain a human population during the peak of the ice age).
The later Angara settlement of 21ka (Mal'ta, Buret artifacts) may indicate a seasonal salmon-run camp from Lake Baikal, after the Lena outlet closed.
here, here and here
[from Darren: sorry for delay, your message got spam-filtered]
>...I am an unashamed fan of non-standard theories, aka fringe theories or whacky theories... ...aquatic ape hypothesis (AAH): that strangely popular notion...
It's a pity you used disparaging terms to introduce such extreme and distorted versions of the theories that most of their supporters would not recognise them. Supporters as disparate as David Attenborough and myself recognise an aquatic influence because it actually does explain more - not surprisingly since it was advocated principally to account for otherwise unexplained evidence. Your sentiment that:
> all of the evidence so far put forward to document our aquatic heritage is demonstrably incorrect...
...would be wrong even without the inadvised 'all'. One awaits such demonstations...
>...and fails to fit the evidence as well as the idea that we originated in woodlands and grasslands.
But it fits perfectly a generalist lifestyle, developing long-distance walking/running, retaining occasional climbing, but also collecting shellfish and pebbles, and seeking water for safety often enough and for long enough to influence us. We don't owe all our distinctive features to water, nor was it a 'marine phase'.
When you move on to ideas of early bipedalism, you introduce that absurd bubble-headed stuff, completely ruining the ground for a sensible consideration of notable paradoxes in ape-human evolution. For types where the stance is reasonably well known (not just teeth), how many African quadrupedals are there between Proconsul and 1 mya from? Any? There's plenty of bipedals of course, including all types near the human-chimp split. This statistical anomaly must be addressed before advocating a quadrupedal human-chimp MRCA.
Didn't you say you were going to look at Filler's paper? When a specialist in spinal surgery at Harvard medical school claims the 20mya spines were more similar to humans' than chimps' are to gorillas', we should consider the implications before doubting him.
Hello John, thank you for your comment. You seem to have completely misunderstood the content of this article. Very briefly...
-- the aquatic ape hypothesis (AAH) proposes that humans went through a marine phase, and that our peculiarities relative to other primates are due to convergence with other mammals of marine or aquatic ancestry. Your comment about 'a generalist lifestyle' involving 'collecting shellfish and pebbles' is therefore not similar to the AAH, so I don't understand why you've leapt to its defence.
-- sorry, but 'all evidence so far put forward to document our aquatic heritage is demonstrably incorrect' is a good summary of the situation. None of the AAH claims have stood up when properly checked.
-- you've somehow totally missed the fact that this article is about the Initial Bipedalism hypothesis, not about the AAH, nor is it about the idea that bipedalism is more primitive within hominoids than conventionally thought. Filler's thesis is that bipedality is primitive in hominoids, and I actually think the evidence for this is both intriguing and good. But it isn't to be confused with de Sarre's writings on initial bipedalism.
The problem with John Jackson's formulation is that this "wading along the shore collecting seashells" is what the AAT/H proponents have been trying to segue to for some time now. The problem is that they still use the small "evidence" and supposed similar characteristics with (virtually always unspecified) aquatic mammals to make their case. This does solve the basic problem the idea had before, and actually creates another.
The first is that thse characteristics are (supposedly but not actually) shared with whales, serenia, and some with seals. These are obviously fully or nearly fully aquatic mammals which have been so for tens of millions of years, becoming highly adapted to their extreme environment (and that's why the proponents are typcially so coy about mentioning just what animals they're talking about, usually preferring to say "aquatics" or "semi-aquatic mammals"). So the characteristics aren't actually the same (hair and fat, for instance, which in humans bears obvious and classic signs of being sexually selected) but they claim they are the same, and the mammals which (supposedly) share them with us have been fully aquatic for several times longer than hominids have existed.
Even the old AAT/H didn't make sense in terms of providing that much selection pressure, not even Hardy's original 6-8 hrs/day for 20-25 million years, certainly not any of the versions since. But now the wading along the coast idea provides even less selection pressure -- far less. The reformulation, rather than help the idea, cripples it. In an attempt to sound less radical, it becomes far more radical, because it nows requires very little selection pressure to create whale and serenia-like adapatations.
And the bottom line is that assuming the supreme environmental generalist among mammals got that way through adaptation to a singular, and extreme, environment, never made sense to start with.
Sorry for the sidetrack; this typically happens in threads where the AAT/H comes up, because there are so mnay misconceptions about it, many seemingly purposely put forth by its proponents and repeated by people who haven't examined the idea very well.
Yes, it made us extinct, because the crocodiles ate us all up...
Really, I'd prefer facing a lion pack on land than a single half-grown crocodile in water. (And lions can swim.)
I've got a couple pages on both terrestrial and aqautic predators on my site, BTW, and the danger one faces from each. It's another of the common claims of the AAT/H which was never examined by the proponents; the so-called safety of water is problematic, to say the least.
BTW, the danger from animals like lions in water (AAT/H proponents have often claimed running into water would be great defense from terrestrial predators) doesn't have much to do with their swimming, but rather the entry into water, when their ability to leap and bound allows them to overtake prey more easily than on land. Big cats actually often chase prey into water for this reason, something even shown on nature shows, although it still seems to have escaped the notice of AAT/H proponents.
Well said - note that there was a tiger culture in Ranthambore National Park where this was the favoured hunting strategy of some individuals. Of further interest is that tigers in the Sundarbans have been documented attacking people in boats.
DM: What seems connected with what?
This: "Earlier post on marine reptiles mentioned inner and outer nostrils,"
With This: "link on front and rear nostrils and how they evolved, regarding the development of the nose, sniffing and underwater breathing and breath-holding."
A note to anthrosciguy: Via free online access (of the "A" section) in the Sage Anthropology Encyclopedia, I found in the Aquatic Ape Hypothesis entry, a statement that humans are the only terrestrial bipedal mammal. I hope this will soon be corrected, as I fear it might be referred to as a "false fact" by AAH/T proponents, which would not advance your noble cause.
The great majority of living terrestrial vertebrates are quadrupeds. Among mammals, bipedalism is a normal method of ground locomotion in various groups of primates (e.g. lemurs, gibbons and Hominina), in the macropods (kangaroos, wallabies, etc.) and in a few groups of rodents (kangaroo mice, spring hares).
Regarding those bounding big cats (including Mario's 'aquatic saber cats' I presume), do you think they would be a threat to human ancestors diving and backfloating offshore along sunny sandy seashores? Or are you thinking of the inland plains cursorial ungulates that bound through shallow water, and then surface swim towards a nearby shore?
Here's a link to a video of a hungry predator bounding through shallow water in pursuit of prey, and a waterside battle, I agree it is terrifying:
baboon vs flamingo
baboon vs crocodile
As to the Initial Biped Hypothesis, well, I must reject it on the grounds that humans are quite capable of backfloating (including infants) while resting, nibbling, chatting etc. but the occiput is immersed during backfloating. This is indicated in Homo erectus (note occiput density), but not in other primates AFAIK.
And so are the ears, which is why I hate backfloating.
Worse yet: what good are our terrestrially-adapted ears when they are immersed in water? It means we can hear neither the crocodiles nor the lions coming. Compare hippos...
Ah. The "inner nostrils" are the choanae, the connections of the nasal cavity to the palate (or throat in the presence of a secondary palate). They are the same thing as the rear nostrils of most "fish"; they moved through the toothrow onto the palate at the origin of Tetrapodomorpha* (best seen in Kenichthys, which has the rear nostrils interrupting the toothrow) and independently at the origin of the lungfishes.
Uniquely among tetrapods, the plesiosaurs seem to have used their nostrils for underwater smelling rather than for breathing, taking water in through the mouth, then into the choanae, and then out through the (outer) nostrils, which, uniquely, are situated behind rather than in front of the choanae -- although this is still not quite clear.
* All that's more closely related to us than to the lungfishes.
Actually, rostrally-located internal nares that have features suggestive of a role in olfaction aren't unique to plesiosaurs but are also seen in placodonts (which are the most basal sauropterygian clade according to most recent phylogenies, suggesting that all sauropterygians might have done this). Ichthyosaurs may have been capable of aquatic olfaction too, with at least some taxa (e.g., some mixosaurs) exhibiting the features that have been associated with aquatic olfaction in plesiosaurs.
Let's not get into Mario "Penguins are fish" Petrinovich. I don't get into the loonier online crowd in my critiques (speaking of which, how's the Traix -- "replaces 80% fossil fueled non-freight motor vehicle transit" -- coming, or your "Siber-Alaskan Solar Pipeline"? Interested parties see "David Deden Designs" for details).
The sentence regarding bipedalism in the Sage Encyclopedia (an article which I wrote) is:
AAT/H proponents concede that bipedalism is not found in any aquatic or semi-aquatic mammal. They use a double standard here, as they commonly argue that the idea that hominids evolved bipedality in a terrestrial setting is badly damaged by the fact that no non-human terrestrial mammal is predominantly bipedal, yet the fact that no aquatic mammal is bipedal is brushed off as irrelevant.
Yes, I think I should have worded that differently, although it's talking about the AAT/H proponent-generated idea that humans are the only terrestrial bipedal mammals and that this can only be explained by aquaticism. In fact the existence of other bipedal mammals does also cut into their belief, but the method of locomotion of those other mammals is really too different from that of humans to be explained by environment, as the AAT/H propoenents insisted must be for that trait. But the sentence as written, which is similar to what I have on my site, does suggest that I agree with their silly supposition that no non-human mammals are predominantly bipedal. I'll have to change that on my site; I'm afraid the encyclopedia article is ink and out of my hands as of a couple years ago.
It's quite obvious predators would be a problem for any version of the AAT/H, and more so than for a terrestrial hominid (for reasons I detail on my site); perhaps it's this reason that the idea's proponents have spent decades ignoring them (after which Morgan handled the problem by making crocodiles "hypothetical"). I'd suggest rather than derailing the comments here further, you could email me directly, or take the AAT/H silliness to a better venue.
0.3 Tc. Oh, sorry, wrong blog.
All this time, I thought the aquatic ape theory was simply that bipedal wading may have played some role in human's evolution of bipedalism, which is frankly alot less preposterous.
Think of it, the ancestral protohuman lives in swamp forest and wades when crossing canals, soon, bipedalism becomes part of the phenotype.
Bipedalism is obviously no aquatic feature: it is seen in birds, many dinos, indris, penguins on land, etc.
Ostriches & most birds have horizontal spines, whereas humans & penguins on land have vertical spines.
For recent insights in human locomotion, please google "econiche Homo" or "aquarboreal".
Marc, please google "walking" and "running" for recent insights into human locomotion.