Hominina

Opisthokonta

The more anthropomorphic primates of the Hominini tribe are placed in the Hominina subtribe. Referred to as hominans, they are characterized by the evolution of an increasingly erect bipedal locomotion. The only extant species is Homo sapiens. Fossil records indicate this subtribe branched from the common ancestor with the chimpanzee lineage about 5 to 7 million years ago, based on mtDNA.

Taxonomy

Current evidence suggests that, about 2.6 million years ago, Australopithecus began to diverge into two paths. One path produced Paranthropus, more robust, specialized in a plant food that required a stronger jaw and molars and powerful facial muscles that required a cranial crest, much like a modern gorilla has, to unite them. The other track led to Homo, with a relatively larger brain, more delicate teeth and jaw. Both genera existed at the same time for about 1 and a half million years.

This subtribe is usually considered to include Australopithecus, Paranthropus, Sahelanthropus, Orrorin, Ardipithecus, Kenyanthropus, and Homo. However, the exact makeup is still under debate, as scientists continue to determine the order of descent in human evolution.

Description

Key features of this group involve various adaptations for living predominantly on the ground rather than on the trees. In particular, it is vertical standing, moving on two legs and the skull placed on top of the vertebral column. The feet are not adapted to grasping and holding unlike the rest of primates, but primarily or solely for bipedal locomotion instead, since the first toe is built robustly and aligned with the other four. The hands have a developed opposable thumb and are quite adept at manipulating objects.