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.