Search results
Results from the WOW.Com Content Network
The terms australopithecines, et. al., come from a former classification as members of a distinct subfamily, the Australopithecinae. [6] Members of Australopithecus are sometimes referred to as the "gracile australopithecines", while Paranthropus are called the "robust australopithecines". [10] [11]
However, such divergence in chewing adaptations may instead have been a response to fallback food availability. In leaner times, robust and gracile australopithecines may have turned to different low-quality foods (fibrous plants for the former, and hard food for the latter), but in more bountiful times, they had more variable and overlapping ...
They are also referred to as the robust australopithecines. They lived between approximately 2.9 and 1.2 million years ago (mya) from the end of the Pliocene to the Middle Pleistocene . Paranthropus is characterised by robust skulls , with a prominent gorilla -like sagittal crest along the midline—which suggest strong chewing muscles—and ...
The genus Paranthropus (otherwise known as "robust australopithecines", in contrast to the "gracile australopithecines") now also includes the East African P. boisei and P. aethiopicus. It is still debated if this is a valid natural grouping (monophyletic) or an invalid grouping of similar-looking hominins (paraphyletic).
Robust australopithecines are characterised by heavily built skulls capable of producing high stresses and bite forces, and some of the largest molars with the thickest enamel of any known ape. P. boisei is the most robust of this group. Brain size was about 450–550 cc (27–34 cu in), similar to other australopithecines.
A similar theory was proposed by Krantz (1975) who argued that Sangiran 6 is: "entirely outside the possible size range of Homo erectus and should be classed as Australopithecus africanus" (i.e. gracile as opposed to robust australopithecine).
The largest sagittal crest ever discovered in the human lineage belongs to the "Black Skull", Paranthropus aethiopicus field number KNM WT 17000, the earliest known robust hominid ancestor and the oldest robust australopithecine discovered to date.
For example, the average cranial capacity for Australopithecines is 440 cc, and the post-orbital constriction index is 0.66. [1] [5] However, with the evolutionary change in brain size in Australopithecines to the Homo genus, the average cranial capacity for Homo Habilis is 640 cc, and the post-orbital constriction index is 0.72.