Aquatic Ape Theory - What is it?

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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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Ardipithecus ramidus

In her 1982 book, The Scars of Evolution, Elaine Morgan argued that a likely area for the cradle of mankind would be in the Danakil Alps in the Afar region of Ethiopia [1]. She suggested that early human ancestors had been cut off from the rest of the continent by an inland sea, thus forcing a rapid shift in evolution between early homininae. This would be the place to look for fossils, she prophetically argued, because bones preserved in silt or mud would have a greater chance of fossilisation.

Then, in 1992–1993 a research team discovered the first A. ramidus fossils—seventeen fragments including skull, mandible, teeth and arm bones in that exact area. More fragments were recovered in 1994, amounting to 45% of the total skeleton. This fossil was originally described as a species of Australopithecus, but White and his colleagues later published a note in the same journal renaming the fossil under a new genus, Ardipithecus. Between 1999 and 2003, the bones and teeth of nine A. ramidus individuals were discovered in the Gona Western Margin of Ethiopia's Afar Region. The fossils were dated to between 4.35 and 4.45 million years old.

Although it seems unlikely that Ardi was a direct ancestor of Homo, the implications are that at least one species of hominin deviated from the family tree due to their enforced dependence on water, possibly leading to bipedalism, or partial bipedalism, orthograde spines (due to swimming or wading) and that their descendents may have followed similar evolutionary deviations in leaving the riverlands and later following the coasts.

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From Wikipedia:

Ardipithecus is a genus of an extinct hominine that lived during Late Miocene and Early Pliocene in Afar Depression, Ethiopia. Originally described as one of the earliest ancestors of humans after they diverged from the main ape lineage, the relation of this genus to human ancestors and whether it is a hominin is now a matter of debate. Two fossil species are described in the literature: A. ramidus, which lived about 4.4 million years ago during the early Pliocene, and A. kadabba, dated to approximately 5.6 million years ago (late Miocene). Behavioral analysis showed that Ardipithecus could be very similar to those of chimpanzees, indicating that the early human ancestors were very chimpanzee-like in behaviour.

The teeth of A. ramidus lacked the specialization of other apes, and suggest that it was a generalized omnivore and frugivore (fruit eater) with a diet that did not depend heavily on foliage, fibrous plant material (roots, tubers, etc.), or hard and or abrasive food.

Some researchers infer from the form of her pelvis and limbs and the presence of her abductable hallux, that "Ardi" was a facultative biped: bipedal when moving on the ground, but quadrupedal when moving about in tree branches.A. ramidus had a more primitive walking ability than later hominids, and could not walk or run for long distances.The teeth suggest omnivory, and are more generalised than those of modern apes.

https://en.wikipedia.org/wiki/Ardipithecus

SCIENTIFIC ARTICLES

On the Environment of Aramis
TE Cerling, FH Brown & JG Wynn 2014
Curr Anthrop 55:469-470

Conclusion: "limited closed canopy likely ass.x riparian habitats, with extensive wooded gransslands & some true grasslands"
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River-margin habitat of Ardipithecus ramidus at Aramis, Ethiopia 4.4 million years ago
M Royhan Gani & Nahid D Gani 2011
Nature Communications 2, 602 doi 10.1038/ncomms1610
http://www.nature.com/ncomms/journal/v2/n12/full/ncomms1610.html?WT.ec_id= NCOMMS-20111220#auth-2

"The nature & type of landscape that hominins (early humans) frequented has been of considerable interest. The recent works on Ar.ramidus (4.4-Ma hominin found at Middle Awash) provided critical information about the early part of human evolution. However, habitat characterization of this basal hominin has been highly contested. Here we present new sedimentological & stable isotopic C & O data from Aramis, where the in situ, partial skeleton of Ar.ramidus was excavated. These data are interpreted to indicate the presence of major rivers & associated mixed vegetations (grasses & trees) in adjacent floodplains. Our finding suggests that (in contrast to a woodland habitat far from a river) Ar.ramidus lived in a river-margin forest in an otherwise savanna (wooded grassland) landscape at Aramis. Correct interpretation of habitat of Ar.ramidus is crucial for proper assessment of causes & mechanisms of early hominin evolution, incl.the development of bipedalism."

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