From Newsgroup: talk.origins
https://www.science.org/content/article/new-study-strengthens-idea-humans-evolved-knuckle-walking-ancestors
https://royalsocietypublishing.org/rspb/article/293/2071/20260556/481780/Did-modern-human-carpal-morphology-evolve-from
The research paper is open access.
When I took physical anthtopology in the mid 1970's it was a contested
issue of whether or not humans had knuckle walking ancestors. Humans
did not show evidence that we evolved from knuckle walkers like chimps
and gorillas. At that time it was still an issue as to whether chimps
were our closest living relatives. The DNA evidence would not be
available until the 1980's, and it was believed that chimps and gorillas
could have evolved knuckle walking after humans split off from the other
great apes.
Since both chimps and gorillas are knuckle walkers and have the same
hand and wrist morphology it is likely that they share a knuckle walking ancestor, but it has been proposed that they developed the trait
independently after humans split off. The common ancestor of chimps and humans was a brachiating ape, but it may not have been terrestrial
enough to have developed knuckle walking.
This research did a high resolution analysis of the carpal bones and
they conclude that humans still retain evidence of a knuckle walking
past. They think that that the counter structural evidence of our other Hominin fossil ancestors is due to how we evolved from knuckle walkers
into upright walking apes. They think that the transitional structure
had to pass through a stage where the bones would have been more like a monkey's than a knuckle walking ape.
Ron Okimoto
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