The Reconstruction of Hominid Behavioral Evolution
While early hominins had important biological differences, they also shared a number of essential characteristics. Most of them were probably just about as efficient as humans were at bipedal movement (3 million years ago).
The bones of their pelvis, or hip area, were reduced from top to bottom and bowl-shaped, similar to humans but not apes. This increased the stability of the pelvis for weight - bearing activities when standing erect or moving bipedally.
Australopithecine and other early hominin fossils have been found only in Africa. The majority of them were discovered in East and South Africa. However, some also were found in Chad, which is located in North Central Africa. Current evidence indicates that there were as many as 12 species of early hominins between 6 and 1.5 million years ago, but they did not all live at the same time. The following species are the most widely accepted ones:
1. Australopithecus anamensis
2.Australopithecus afarensis
3.Australopithecus africanus
4.Paranthropus aethiopicus (or Australopithecus aethiopicus)
5.Paranthropus boisei (or Australopithecus boisei)
6.Paranthropus robustus (or Australopithecus robustus)
There has been a breach in the fossil hominin record for the critical time preceding the appearance of Australopithecus anamensis 4.2 million years ago. New findings are now emerging to fill in the gaps in the picture of evolution that led to the emergence of the australopithecines at that early stage.