Australopithecus sediba

Extinct species of hominin

Australopithecus sediba is an extinct species of hominin that lived approximately 1.98 million years ago during the early Pleistocene in what is now South Africa. The species was first described in 2010 following the discovery of fossils at the Malapa Fossil Site in the Cradle of Humankind, a UNESCO World Heritage Site.

Discovery

The first fossils of Australopithecus sediba were discovered in 2008 by a team led by Lee Berger, a paleoanthropologist at the University of the Witwatersrand. The initial discovery included a partial skeleton of a juvenile male, designated as MH1, and a partial skeleton of an adult female, designated as MH2. These fossils were found in a collapsed cave system at Malapa, which provided excellent preservation conditions.

Morphology

Australopithecus sediba exhibits a unique combination of primitive and derived traits. The species has a small cranial capacity, similar to other australopiths, but shows more advanced features in the pelvis and lower limbs, suggesting bipedal locomotion. The hands of A. sediba are also notable for their precision grip, which may indicate tool use.

Skull and Dentition

The skull of Australopithecus sediba is small, with a brain size of about 420 to 450 cubic centimeters. The face is less prognathous than that of earlier australopiths, and the teeth are relatively small with a modern-like dental arcade.

Postcranial Skeleton

The postcranial skeleton of A. sediba shows adaptations for both arboreal and terrestrial locomotion. The pelvis is broad and similar to that of early Homo, while the legs and feet suggest a bipedal gait. However, the arms are long, indicating that climbing was still an important part of their behavior.

Significance

The discovery of Australopithecus sediba has provided valuable insights into the evolution of early hominins. The mix of traits seen in A. sediba suggests it may represent a transitional form between the australopiths and the genus Homo. This has implications for understanding the origins of bipedalism and the development of traits associated with modern humans.

Also see

• Australopithecus afarensis
• Australopithecus africanus
• Homo habilis
• Cradle of Humankind