More than a million years before the first hominid known as Lucy crossed the lesser-known distant region of Ethiopia Ardipithecus ramidus he wandered about the same area. Now, a team of anthropologists has analyzed the fossilized hand from 4.4 million years ago a copy (affectionately called “Ardi”), and argue that the roaming of human ancestors may have involved more swaying among the trees than previously thought.
Published on Wednesday in the journal Science Advances, the team’s comparative analysis focuses on Ardi’s hand morphology in the context of extinct and existing relatives. In the conversation with bones from other places in our family tree, Ardi’s hand features indicate when specific adaptations currently observed in different primates occurred. Specifically, knowing how Ardi moved brings us closer to knowing how we (homo sapiens) became a group of terrestrial and bipedal primates.
The team of Thomas Cody Prang, a biological anthropologist at Texas A&M University and lead author of the recent article, pointed out some key traits in Ardi’s hand that indicated how he might have moved. The phalanges of the specimen were long relative to the estimated body size. Those bones too curved inward, suggesting that the hand was predisposed to grab her. “The fact that Ardipithecus overlaps in the length and curvature of the fingers with the more suspensive primates strongly implies that Ardipithecus adapted to the suspension,” Prang said.
“Now, that doesn’t mean that, as you know, humans evolved from an ancestor that looked exactly like a chimpanzee,” he added in a phone call. “It does not mean that chimpanzees are living fossils or that the chimpanzees themselves have not evolved. Instead, our study proves it Ardipithecusand the earliest human fossils probably retain characteristics of an ancestor that is more like chimpanzees and bonobos than any other living primate. “
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Originally excavated and described in the early 1990s by a team led by paleoanthropologist Tim White, Ardipithecus ramidus received more attention after 2009 description of a partial skeleton (nicknamed Ardi) in the journal Science. White disagrees with the findings of the recent paper, based on the specific bones and specimens selected for analysis and the exclusion of others.
“We do not discuss the well-established fact that the human hand evolved over time. However, there is no new data or interpretation here, “White wrote in an email. “We cannot take these authors seriously until they understand the unique anatomy of Ardi’s hand, rather than using limited and selected measures in a post hoc argument that supports the discredited notion that our ancestors were specifically similar. to chimpanzees “.
If you’re relatively new to the debate about the nature of human origins and how our ancestors may have walked on the ground or turned in the trees, be prepared to hang out. In 2009, White’s team argued that Ardi had no characteristics to indicate that he was fit for a monkey-like life; these absent features included a morphological configuration for swinging between the trees and climbing them and walking on the knuckles. White’s team suggested that the last common ancestor between humans and chimpanzees was probably quite different from any existing ape.
Prang’s team argues otherwise in this paper, claiming that the ancestor (who preceded Ardi) was closer to chimpanzees than anything else. They continue to report that the most human hands emerge first with the most familiar Australopithecus afarensis, Lucy species.
The scarcity of the fossil record doesn’t help much, though Ardi’s hand is more complete than young Lucy’s. Prang added that Ardi’s hand interpretations are useful in reducing the goals of what might have been the circumstances of his evolution (and, by representation, what arose before and after Ardi).
“It illustrates the point that in science we are not proving that something is true. Instead, we rule out hypotheses and alternatives that are likely to be false, “Prang said.” In this case, I think we can rule out the hypothesis that humans evolved from an ancestor that had no suspenseful characteristics and d ‘an ancestor who was more like a monkey. Ardipithecus“.