…from people more knowledgable than me.
Holly Dunsworth, at The Mermaid’s Tale, has a long post that touches on a number of questions raised by the new fossils. One point I like that she highlights is the variation seen within the locomotor repertoires of extant primates that we generally type-cast as “knuckle-walkers” or “arboreal/terrestrial quadrupeds” or “suspensory climbers”:
That’s not because we don’t know how anatomy and behavior are linked in extant humans, apes, monkeys, etc… we seem to have a pretty good handle on that. At least big picture. The problems arise when you zoom in. Are chimpanzees really arboreal? Yes. Are they really terrestrial? YES. Same for gorillas.
So reconstructing an evolutionary scenario in which our hominin ancestors went from a state of arboreality to a state of terrestriality is not that simple. The Burtele foot descriptors definitely understand this. It’s just the popular media that doesn’t have the time or the inclination to get this. Hence my intro above.
She then goes into a discussion of locomotor strategies and functional anatomy from a developmental perspective:
The arboreal use of the strong grasping big toe is not necessarily about climbing or even walking on limbs;** it’s probably more about suspension.Suspensory behavior is typified by the gibbons, orangutans (many at least), and the rest of the apes and so is the grasping big toe. That’s the strongest functional explanation for the ape’s thumblike big toe.
….
So think about who’s doing much of the suspension particularly in African apes: Juveniles.
She then goes into some data from her dissertation on this issue, which I’ll leave you to discover by clicking over.
Zach Cofran, at Lawn Chair Anthropology, has his own review of the paper interspersed with his thoughts, but raises a very salient point at the end:
I’ve long been suspicious that nearly every single ape-like (including humans) fossil found in Africa younger than 7 million years is attributed to the hominid line. I’d be very pleased if this turned out to be a non-hominid ape. (though again I don’t necessarily think that’s what the Burtele fossils are).
I’ll add more comments as I find them.
