Aquatic Ape Theory - What is it?

A Brief Summary of AAT - key arguments

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When / Where / How?

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... Anatomical Evidence
... Bipedalism
... Birth and babies
... Brain
... Breath control
... Descended larynx
... Diet
... Diseases
... Fat
... Fingers, toes and feet
... Furlessness
... Hair and baldness
... Human ailments
... Kidneys
... Language & Song
... Menopause
... Nose
... Olfactory sense
... Pachyostosis
... Paranasal Sinuses
... Platycephaly
... Reverse osmosis
... Sexual features
... Sleep (USWS)
... Surfer's ear
... Sweating
... Tears
... Underwater vision
... Viruses
... Waterside environments

. Homo Ancestors
... Trachillos bipedal hominids
... Homo erectus
... Homo neanderthalensis
... Sea Gypsies/ the Moken
... Homo sapiens - water afinity
... Coastal Migration
... Pan and Gorilla ancestry
... Semi-Aquatic Animals

. Testable Hypotheses
. Fossil evidence
. Genetic evidence
. Paleoecological evidence
. Retroviral marker in apes
. Acheulean handaxes

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Faces

"Humans have orthognathic faces, that is, faces that lie almost entirely beneath the anterior cranial fossa, whereas other apes (and primates in general) have prognathic faces that project forward of the anterior cranial fossa. Prognathism has been variously defined by different researchers, and is taken by some to refer only to projection of the lower facial skeleton (in which case projection of the upper portion of the face is referred to as “facial projection” rather than prognathism), and by others to refer to overall facial projection. By either definition, humans have less prognathic faces than chimpanzees, gorillas and orangutans. Prognathism is usually measured with the craniofacial angle (also known as the sphenomaxillary angle), which is the angle formed in the sagittal plane between the most anterior points on the maxilla, sphenoid and foramen magnum (because these landmarks can be difficult to observe in intact crania, this angle is generally quantified as the angle between the Frankfort horizontal and a line passing through the osteometric landmarks sellion and prosthion). This angle is obtuse in the great apes and acute in modern humans. The evolution of an orthognathic face in humans is likely related to a reduction in the size of teeth and chewing muscles, and perhaps to changes in masticatory load arm/lever arm relationships reflecting a reduced need for production of powerful bite forces in the anterior dentition.  Both of these changes may reflect dietary shifts in human evolution away from tough skinned fruits and fibrous plant matter and towards greater consumption of meat and cooked foods." [1]

According to Marc Verhaegen, the following confirms his view that Homo neanderthalis often dived for food, e.g. waterlily roots in freshwater & shellfish at coasts, according to the season.
- Hn = platycephaly + protruding mid-face (retro-molar space) & big nose surrounded by large air sinuses,
- Hs = flat face, high skull, very long legs, base-cranial flexion, for looking down for food, wading in very shallow waters.

Study differentiates facial growth in Neanderthals and modern humans

An international research team, led by Rodrigo Lacruz, PhD, assistant professor in the Department of Basic Science and Craniofacial Biology at New York University's College of Dentistry (NYUCD), has just published a study describing for the first time the developmental processes that differentiate Neanderthal facial skeletons from those of modern humans.

Lacruz's research team showed that the Neanderthals, who appeared about 200,000 years ago, are quite distinct from Homo sapiens (humans) in the manner in which their faces grow, adding to an old but important debate concerning the separation of these two groups. "This is an important piece of the puzzle of evolution," says Lacruz, a paleoanthropologist and enamel biologist. "Some have thought that Neanderthals and humans should not be considered distinct branches of the human family tree. However, our findings, based upon facial growth patterns, indicate they are indeed sufficiently distinct from one another.

Growth directions of the maxilla in the Sima de los Huesos (SH) and Neanderthals compared to modern humans. This impacts facial growth in at least two ways. (i) Extensive bone deposits over the maxilla in the fossils are consistent with a strong forward growth component (purple arrows); whereas resorption in the modern human face attenuates forward displacement (blue arrow). (ii) Deposition combined with larger developing nasal cavities in the fossils displaces the dentition forward generating the retromolar space characteristic of Neanderthals and also in some SH fossils [Credit: Rodrigo S Lacruz]

Read more at: http://archaeologynewsnetwork.blogspot.be/2015/12/study-differentiates-facial-growth-in.html?

Comments:
Very beautiful article. It illustrates how important the neandertal protruding mid-face & big nose were. The comparative evidence shows that our Pleistocene were no open plain dwellers (sweating water + salt = scarce on savannas) as still sometimes assumed. Instead, early-Pleistocene Homo dispersed intercontinentally along African & Eurasian coasts, beach-combing, diving & wading bipedally for littoral, shallow-aquatic & waterside foods (rich in brain-specific DHA). Later, neandertals followed the rivers inland, feeding partly on cattails (traces on their handaxes), waterlily roots (traces in their dental plaque), salmon etc., but seasonally still collected shellfish at the Atlantic, Northsea & Mediterranean coasts (from Gibraltar to Petralona) - google econiche Homo. H.sapiens (in Africa) abandoned frequent diving, they became very long-legged waders-walkers with more complex tools & distance weapons, who looked down to spot edible foods in very shallow waters, lost platycephaly & pachyostosis, mid-facial projection & very big noses as in neandertals, and developed flat faces, basi-cranial flexion & high skulls with more downward looking eyes than in archaic Homo - google researchGate marc verhaegen (2013 Hum.Evol.28:237-266).

Marc Verhaegen December 9, 2015 at 3:51 AM

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