The robust australopithecines existed between 2.5 and 1.5 million years ago. At this station are skeletal remains from two kinds of robust australopithecine. You have already met Australopithecus robustus earlier in the semester. The new species for you here is Australopithecus boisei. This species had the largest molar and premolar teeth of any hominin ever to have existed.
A. boisei comes from East Africa, with remains found in Ethiopia, Kenya, and Tanzania. The most famous fossil is OH 5, from Olduvai Gorge, Tanzania, around 1.7 million years old. Other significant specimens here include KNM-ER 739, KNM-ER 732 and KNM-ER 406, from Koobi Fora, Kenya, around the same age.
The specimens of Australopithecus robustus here will be familiar to you. All are from South Africa, and they include SK 48 and SK 12, from Swartkrans, South Africa, around 1.7 million years old, and TM 1517 from Kromdraai, South Africa, around 1.8 million years old.
These species may be closely related, but there are some differences between them. Examine them closely with the following questions:
The defining features of the robust australopithecines are the large postcanine dentition and large jaw musculature. How do these two groups of fossils compare on those features?
Robust australopithecines also have a very reduced anterior dentition (incisors and canines). Which fossils show that morphology?
The premolars in these species have enlarged, at the extreme they become more like molars in their morphology. Which fossils have the most molar-like premolars? Is the trend the same in the upper and lower dentitions?
With such great robusticity of the jaws and teeth, there are potentially great differences between males and females. Are the differences here consistent with sexual dimorphism? Which fossils are male, and which are female?