The Origins of Bipedal Locomotion
William EH Harcourt-Smith 2013
Handbook of PA doi 10.1007/978-3-642-27800-6_48-3

BPism is a highly specialized & unusual form of primate locomotion, found today only in modern Hs.
Most extinct taxa within the Hominini were BP, but the degree to which they were BP remains the subject of considerable debate.
The signifficant discoveries of fossil hominin that remains in the last 40 yrs have resulted in this debate becoming increasingly focused on how BP certain fossil taxa were, rather than on the overall process.
The early hominin fossil record remains poor, but evidence points to at least 2 distinct adaptive shifts:
1) There was a shift to habitual BPism, as typiffied by certain members of Australopithecus,
but possibly incl. earlier genera, e.g. Ardipithecus & Orrorin.
Such taxa were BP, but also retained a nr of signifficant adaptations to arboreal climbing.
2) The 2nd shift was to fully obligate BPism, it coincides with the emergence of the genus Homo.
By the early-Pleistocene, certain members of Homo had acquired a post-cranial skeleton indicating fully humanlike striding BPism.
The final part of this chapter reviews why BPism was selected for.
There have been many theoretical explanations,
the most robust remain those linked to the emergence of more varied habitats. Such an environmental shift would have involved strong selection for new behavioral strategies, most likely linked to the efficient procurement of food.

_____

Early Hominoidea >10 Ma were already BP, not for running after antelopes of course, but simply for
- frequent wading in swamp forests &
- climbing arms overhead in the branches above the swamp.
Google e.g. "aquarboreal".

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On Sunday, November 20, 2022 at 2:49:32 PM UTC-5, littor...@gmail.com wrote:

The Origins of Bipedal Locomotion
William EH Harcourt-Smith 2013
Handbook of PA doi 10.1007/978-3-642-27800-6_48-3

BPism is a highly specialized & unusual form of primate locomotion, found today only in modern Hs.

Sifaka.

You're welcome.

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DD'eDeN aka note/nickname/alas_my_loves wrote:

Sifaka.

They're an arboreal species, nimrod.

Calling them bipedal is like calling the Atlantic Ocean a large
pile of salt. It is salty, there is a lot of salt there, but it's a
body of water not a pile of salt.





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https://jtem.tumblr.com/post/701569038790377472

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Op maandag 21 november 2022 om 05:20:35 UTC+1 schreef DD'eDeN aka note/nickname/alas_my_loves:

The Origins of Bipedal Locomotion
William EH Harcourt-Smith 2013
Handbook of PA doi 10.1007/978-3-642-27800-6_48-3
BPism is a highly specialized & unusual form of primate locomotion, found today only in modern Hs.

Sifaka.

You're welcome: yes, I should have written vertical BPism.
I just commented this on a recent paper of Bernard Wood:
doi 10.1093/actrade/9780198831747.003.0006
"Archaic and transitional hominins":
This article assumes that australopiths ("bipedal") are closer relatives of us ("hominins") than of Pan or Gorilla, but this is wrong, e.g. retroviral evidence places human Pliocene ancestors with Asian primates (e.g. C.T.Yohn cs 2005 PLoS Biol.3:1-11),
and bipedalism does not discern us from the other Hominoidea (e.g. the Trachilos BP footprints c 6 Ma): all apes had vertical Mio-Pliocene ancestors, google "aquarboreal".
Apparently, E.African a'piths were fossil relatives of gorillas, and S.African a'piths, of bonobos & chimps: they evolved in parallel from late-Pliocene "gracile" afarensis//africanus to early-Pleistocene "robust" boisei//robustus to extant knuckle-
walking Gorilla//Pan (e.g. 1994 Hum.Evol.9:121-139, 1996 Hum.Evol.11:35-41, 2013 Hum.Evol.28:237-266). Meanwhile, Homo followed the S.Asian coasts as far as Java & Flores, google "coastal dispersal Pleistocene Homo".

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