Bipedal locomotion in zoo apes:
Revisiting the hylobatian model for bipedal origins
Kyle H Rosen cs 2022 Evol.Hum.Sci. doi org/10.1017/ehs.2022.9
BP locomotion is a hallmark of being human.
(?? hylobatids, kangaroos, birds... --mv)
Yet the body form from which BPism evolved remains unclear.
(no!! google "aquarboreal" --mv):
the positional behaviour (ortho- vs pronograde) & lumbar spine length (long+mobile, vs short+stiff) of the Afr.ape-Hs LCA require further investigation.
Fossil evidence would be the most conclusive,
but the paucity of hominid fossils from 5–10 Ma makes this challenging.(paucity? Oreo-Ourano-Graecopith were hominid & aquarboreal, Trachilos footprints were BP: late-Miocene hominids were BP=aquarboreal in Medit.swamp forests --mv)
In their absence(?? --mv), extant primate anatomy & behaviour may offer some insight into the ancestral body form from which BPism could most easily evolve.
(yes, google "aquarboreal" --mv)
Here we quantify the frequency of BPism in 496 zoo-housed hominoids & cercopiths. Our results:
each ape+monkey species can move BPally,
but hylobatids are much more BP: more frequently & for greater distances.
(yes, see our Med.Hypoth. & Hum.Evol.papers --mv)
These data support hypotheses of an orthograde, long-backed(?? apes: less lumbar vertebrae < OWMs --mv) & arboreal LCA, consistent with mid-to-late-Miocene hominoid fossils.
(of course: the hominoid LCA was already BP & aquarboreal --mv)
If true, KWing evolved in parallel in Pan // Gorilla,
the human body-form, particularly the long lower back(?? 5 lumbar vertebrae, 7 in cercopiths --mv) & orthograde posture, is conserved.
(KWing Pan//Gorilla, see already my papers 1985 Med.Hypoth.16:17 & 1994 Hum.Evol.9:121 --mv)


IOW, this beautifully confirms our view:
Mio-Pliocene Hominoidea were already BP=aquarobreal in coastal & swamp forests: they waded upright + climbed arms overhead in the branches above the water. https://www.sciencedirect.com/science/article/abs/pii/S0169534702024904

This also implies that BP apiths were related to Gorilla or Pan (E & S.Afr.apiths resp.: Pliocene Homo = S.Aian coasts), see my papers
1994 Hum.Evol.9:121-139 &
1996 Hum.Evol.11:35-41 https://www.academia.edu/8732353/Marc_Verhaegens_papers_in_Human_Evolution Pliocene Homo was on his way to Java (Mojokerto early-Pleist.), see my book p.299-300, google "GondwanaTalks Verhaegen"
https://www.gondwanatalks.com/l/the-waterside-hypothesis-wading-led-to-upright-walking-in-early-humans/

:-)

Only *incredible*imbeciles believe their Pleist.ancestors ran after antelopes!! :-DDD

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