(ORDO NEWS) — Some of the key lifestyle and anatomy transformations that shaped our view began long before humans appeared. So, the transition to upright posture is usually referred to Australopithecus, various species of which lived in Africa and are considered the ancestors of the human race. It is not surprising that it is on these extinct primates that anthropologists study the changes that accompanied the transition from climbing trees to walking on two legs.
It was this transition that released the forelimbs for instrumental activity, and the first Homo already deftly used their hands for subtle manipulations, anatomically inaccessible to purely climbing primates. The new work done by the team of the University of Kent professor, Tracy Kivell, also points to it. Its results are presented in an article published in the journal Nature Ecology & Evolution .
Scientists analyzed the internal structure of bone tissue and joints of the Australopithecus sediba hand (recall, earlier, by the example of the anatomy of these primates, it was shown how much easier it was for our ancestors to give birth). Data for A. sediba were compared with the brush structures of other Australopithecines ( A. africanus and A. afarensis ), as well as with the hands of Neanderthals and sapiens.
It was found that the structure of the bones of the proximal (first) phalanges of the fingers in Australopithecus sediba indicates the use of the hand to capture branches during climbing. On the other hand, the structure of the joints of the thumb suggests that the hand also performed more complex manipulations. According to scientists, this anatomy indicates the transitional nature of the structure – and the gradual transition of Australopithecus from climbing to upright posture with a slow release of hands for instrumental activity.
“The internal structure of the bones reveals hidden evidence of the behavior of ancient human relatives,” adds Tracy Kidwell. – We were amazed to find that Australopithecus sediba has such an unusual character for using Australopithecus hands. Fossils reveal more and more new forms of diverse ways of movement and interaction with the outside world that our ancestors tried out.”
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