Blogs » Neurognosis » Another one to add to the Australopithecus bunch

Subscribe


 
Another one to add to the Australopithecus bunch
By Crobar in Neurognosis
April 9, 2010

For a while in the scientific community a question has gone without answer and caused much debate. That question being, which hominid genus gave rise to our own Homo genus? Many scientists have long contended that Homo evolved from the Australopiths however, others disagreed and viewed specimens such as Kenyanthropus platyops as the ancestors of the first human species classified as Homo habilis which appeared nearly 2 million years ago.

Well, that debate has some new evidence to ponder in the way of new specimens of Australopiths discovered in South Africa. The specimens are thought to represent a new species of Australopiths - Australopithecus sediba. The specimens are very Australopithecine, however also show some traits which are present in Homo habilis. The specimens' pelvic and dental features set them apart from other Australopiths and these features are closer to those seen in the first human species Homo habilis.

The uranium-lead dating of the flowstone just below the specimens was dated at approximately 2.026 million years old and a palaeomagnetic date of the sediment deposition of the layer containing the specimens between 1.95 and 1.78 million years ago. That would place the specimens close to or right next to (in time) the oldest known specimens of Homo habilis which are approximately 1.8 million years old. Early humans such as habilis more closely resembled Australopiths than AMHs (anatomically modern humans). The advent of more modern morphology and especially the use of tools is what set habilis apart from previous species, however Australopithecus garhi specimens were reported in a paper in 1999 to have been found with tool implements around 2.5 million years ago. Some confusion? Possibly, however such blurring of species lines and overlap in characteristics is exactly what one would expect from evolutionary change.

Palaeoanthropology in the past few decades has seen the human evolutionary lineage go from being possibly unique in its lack of cladistic branching to specimens being discovered to amend that inaccurate conclusion.

Whether A. sediba represents a direct ancestor of the humnan lineage or not, the discovery of these unique specimens is intriguing nonetheless.