I’ve been under the radar for several days.
I’ve been struggling to understand this paper, “Homeotic Evolution in the Mammalia: Diversification of Therian Axial Seriation and the Morphogenetic Basis of Human Origins,” from Aaron Filler of Harvard’s Anthropology department. All I can really make sense of it is that there’s a probability that bipedalism originated way earlier than we think right now. And that chimpanzees, gorillas, and the like, were mutants that reverted back to a more primitive primate body plan.
Filler suggests this because of a transformed hominiform type of lumbar spine found in Morotopithecus bishopi, an extinct hominoid species that lived in Uganda more than 21 million years ago. In the paper he compares human vertebra to the Morotopithecus, which both show an absence of the styloid process and relocation of the lumbar transverse process. Because of this transformation, he suggests Morotopithecus, along with three upright bipedal species from the Early Miocene, were bipedal long before any Australopithecine.
His analysis is very thorough but it is honestly hard to accept. If you wanna read more about Morotopithecus, you maybe interested in this, “Postcranial functional morphology of Morotopithecus bishopi, with implications for the evolution of modern ape locomotion.”