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The robust australopithecines, members of the extinct hominin genus Paranthropus, were bipedal hominins that probably descended from the gracile australopithecine hominins (Australopithecus). All species of Paranthropus were bipedal, and many lived during a time when species of the genus Homo (which were possibly descended from Australopithecus or more likely from Kenyanthropus), were prevalent. Paranthropus first appeared roughly 2.7 million years ago, just before the beginning of the Pleistocene. Most species of P. boisei had a brain about 40 percent of the size of modern man. There was some size variation between the different species of Paranthropus, but most stood roughly 1.3-1.4 m tall and were quite well muscled. Paranthropus is thought to have lived in wooded areas rather than the grasslands of the Australopithecus.

The behavior of Paranthropus was quite different from that of the genus Homo, in that it was not as adaptable to its environment or as resourceful. Evidence of this exists in the form of its physiology which was specifically tailored to a diet of grubs and plants. This would have made it more reliant on favorable environmental conditions than members of the genus Homo, such as Homo habilis, which would eat a much wider variety of foods.

Opinions differ as to whether the species P. aethiopicus, P. boisei and P. robustus should be included within the genus Australopithecus, due to the unknown last common ancestor. The emergence of the robusts could be either a display of divergent or convergent evolution. The current consensus in the scientific community is that they should be placed in a distinct genus, Paranthropus, which is believed to have developed from the ancestral Australopithecus line. Up until the last half-decade, the majority of the scientific community included all the species of both Australopithecus and Paranthropus in a single genus.

For the most part the Australopithecus species A. afarensis, A. africanus, and A. anamensis either disappeared from the fossil record before the appearance of early humans or seem to have been the ancestors of Homo habilis, yet P. boisei and P. aethiopicus continued to evolve along a separate path distinct and unrelated to early humans. Paranthropus shared the earth with some early examples of the Homo genus, such as H. habilis, H. ergaster, and possibly even H. erectus. Australopithecus afarensis and A. anamensis had, for the most part, disappeared by this time. There were also significant morphological differences between Australopithecus and Paranthropus, although the differences were found on the cranial remains. The postcranial remains were still very similar. Paranthropus was more massively built, specialized, and tended to sport gorilla-like sagittal crests on the cranium upon which massive jaws were anchored. It seemed to be evolving away from human-likeness, not toward or preceding it. The contrast between Paranthropus and Homo was even greater.

Species of Paranthropus were not as advanced in intellect as species of Homo, yet they had significantly larger and more advanced brains than Australopithecus. There is even evidence that some species of Paranthropus were using tools similar to that used in the Lower Paleolithic era, known as the Oldowan technology, though they were not quite as advanced as those used by Homo habilis. Species of Paranthropus almost certainly did not use language or control fire.

Paranthropus boisei was discovered by Mary Leakey in 1959 at Olduvai Gorge in Tanzania (specimen OH5). The species was originally named Zinjanthropus boisei by the Leakeys, apparently ignoring Dr. Robert Broom's original Paranthropus name, later assigned to the Australopithecus genus which was then split as described above.

See also

• Cranial capacity

Footnotes

1. There is equivocal, though difficult to refute, evidence that some late representatives of Paranthropus robustus were using some uncharacteristically advanced tools and even using fire. This might suggest that the last remnants of Paranthropus were associating with and adopting the culture of H. erectus prior to their disappearance from the fossil record; technology through imitation rather than innovation. The evidence comes from Swartkrans, South Africa and is probably the second oldest evidence of fire. In any case, it can be fairly surmised that the controlled use of fire was extremely atypical of P. robustus and very little of what is known of the hominid's behavior based on its physiology and its use of tools supports the notion that it would be able to accomplish such a feat through independent invention.

External links

• Mikko's Phylogeny Archive

• Early hominids
• Pliocene mammals
• Pleistocene mammals
• Pleistocene extinctions