The more anthropomorphic primates of the Hominini tribe are placed in the Hominina subtribe. They are characterized by a progression of increasingly erect bipedal locomotion. The only existing species is Homo sapiens. Fossil records indicate this subtribe branched from the common ancestor with the chimpanzee lineage about 3-5 million years ago.
This subtribe is usually described to include Australopithecus, Paranthropus, Sahelanthropus, Orrorin, Ardipithecus, and Homo. However, the exact makeup is still under debate, as some scientists struggle to determine the order of descent in human evolution.
Key features of this group involve various adaptations for living terrestrially instead of arboreally. One feature is an erect bipedal stance and the skull placed on top of the vertebral column. The feet are not prehensile unlike the rest of primates, because the first toe is but robust and aligned with the other four. The hands have a developed opposable thumb and are quite adept at manipulating objects.
Currently it is believed that about 2.6 million years ago, Australopithecus began to diverge into two parallel paths, on the one hand to Paranthropus, more robust, specialized in an herbivorous diet that required a stronger jaw and molars and powerful facial muscles that required a cranial crest to unite them. The other track led to Homo with a relatively larger brain, more graceful teeth and jaw. Both genera existed at the same time for about a million and a half years.
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