Chapter 17 - Fossil Hominins, the Bipedal Primates

Abstract

The earliest hominins are from the late Miocene of Africa.The relationships among the three Miocene genera are unclear, but all had reduced canine teeth and were probably bipedal to some extent. The genus Australopithecus is a widespread, paraphyletic taxon known from Pliocene deposits throughout Africa. Compared with living humans, Australopithecus had large molar teeth with thick enamel and a small brain; it was an herbivorous biped but also showed forelimb features, such a curved phalanges and a cranially oriented scapula, suggesting arboreal abilities. Paranthropus from the late Pliocene and early Pleistocene had even larger molar and premolar teeth and a short broad face. The genus Homo is characterized by a reduced dentition, a larger brain, a more slender truck, and use of stone tools. Our genus first appeared in the latest Pliocene, and there were several species in the early Pleistocene. Homo erectus is the first hominin that dispersed from Africa and in the early Pleistocene is found in both western and Eastern Asia as well as Africa. Homo erectus used stone tools, and seems to have relied on animal food. Its success may have been due to its abilities to run as well as walk, and an ability to cook food. The middle Pleistocene Homo heidelbergensis is a paraphyletic taxon that probably gave rise to H. neanderthalensis in Europe and to the lineage leading to Homo sapiens in Africa. Homo floresiensis, the “Hobbit”, in a late Pleistocene species from southeast Asia that seems to be a relic lineage from the earliest Pleistocene. Modern humans, H. sapiens, appear in Africa approximately 200,000 years ago, but only dispersed to Eurasia and Australia in the last 100,000 years, and into the Americas in the last 20,000 years. Compared with other, earlier hominin species, modern humans are characterized by a rich archeological record containing a wide array of tools, art, and language.