Paranthropus robustus

Skull of a Paranthropus robustus SK 48

• South Africa, Tanzania

Paranthropus robustus ( Australopithecus robustus also ) is an extinct species of the genus Paranthropus from the Hominini. He had, therefore, sometimes referred to a similar body such as Australopithecus africanus, but a larger, more powerful and more massive skull teeth and is also called " robust australopithecines ". He lived in the Lower Pleistocene ( Gelasian and Early Pleistocene ), in about 2.0 to 1.5 million years.

The species of the genus Paranthropus be expected in a group of Australopithecina and likely represent an evolutionary sideline to the genus Homo dar.

Naming

The name of the genus Paranthropus is derived from ancient Greek ἄνθρωπος anthropos ( "man" ) and para ( " beside ", " notwithstanding "). The epithet robustus alludes to its robust ' physique. Paranthropus robustus thus means ' robust fellow man. "

Holotype

First skull fragments with the archive number TM 1517 found by schoolboy Gert Terblanche, 1938 in a quarry in Kromdraai in South Africa. Robert Broom, the scientifically supervised the fossil record of the quarry, recognized its importance and described the new finds in the same year as the holotype of the new species Paranthropus robustus. Broom presented the findings thus not aware of the hominids of the genus Australopithecus.

In 1948 Broom discovered in the cave of Swartkrans, which is just 1.2 kilometers from Sterkfontein, the fossil SK 6, consisting of the part of a lower jaw and some teeth, which he initially called Paranthropus crassidens (from Latin. Crassus = thick and dens = tooth). This additional species name has, however, not enforced, as it is obviously also Paranthropus robustus is. SK 6 is now considered as the second type specimen of Paranthropus robustus.

More fossil finds

In the following two years, complete skulls were found in the cave of Swartkrans: first in 1949, the fossil with the designation SK 79, which, however, was strongly crushed by sediment and therefore scientifically limited relevance. On June 30, 1950 relatively completely preserved skull with the Fossil name SK was during blasting in the cave that served the commercial mining of limestone, 48 exposed ( see figure in the Taxobox ). This contained in the maxilla still a canine, two premolars and five molars. The skull was with his head crest, the strong zygomatic arches and the depressed nasal area important for the characteristic morphology of the robust australopithecines. Broom held this individual for a female. His anatomical description, from which he graduated in 1951 appeared posthumously in a comprehensive monograph.

A particularly well-preserved skull DNH 7 was found in 1994 in the caves of Drimolen ( South Africa). Other important sites is Coopers Cave near Swartkrans and Gondolin Cave in the North-West Province.

Appearance

Paranthropus robustus was attributed to a body height of 1.10 up to 1.30 m and a weight of 40 to 80 kg. The massive face is flat, without end and has large brow ridges. He had relatively small incisors and canines, but massive grinding teeth in a large lower jaw. Most specimens have a head crest. These features suggest that its diet is likely to have predominantly consisted of coarse, tough food that required a lot of chewing. It has been proven that he is - similar to the earliest members of the genus Homo and Australopithecus africanus as - fed more than 50 percent of its daily calorie intake of C3 plants and to a further significant proportion of C4 plants.

The average brain size is about 515 cc and thus around 100 cm ³ larger than that of living chimpanzees. Bones that were excavated with Paranthropus robustus skeletons, suggest that they might have been used as grave poles.

Although there are only a few preserved bones from the area below the head; the existing fragments of the hip joint and knee joint but were interpreted as showing that Paranthropus robustus could very likely run at least temporarily bipedal.

One of the oldest human-like anatomical features, the shape of the anvil in the middle ear, which is already for Australopithecus africanus and Paranthropus robustus occupied ( at Fossil SKW 18 from Swartkrans ) and probably different from the shape of the anvil in chimpanzees already in their last common ancestor.

Behavior

Probably Paranthropus robustus lived in the savannas and could also exploit coarse and zähfaseriges plant material there. Some skeletal remains also suggest that he or occasionally larger predators regularly fell victim to.

A close examination of teeth of an upper jaw from the Swartkrans cave using the laser ablation showed that this individual must have taken seasonally changing food to himself at times relatively soft leaves of deciduous trees and at times relatively hard seeds and other plant parts of grasses, similar to living today steppe baboons. The teeth of three other individuals turned up evidence of a far less specialized and at least temporarily softer foods, as they had been due to the massive molars attributed by then.

2007 a ​​group of researchers analyzed the correlation of skull size and loss of tooth substance at 19 skulls and 16 mandibles, in each of which the molar M3 ( " wisdom teeth " ) was already broken. It has been reported that young male adults had ( identified due to the low loss of dental hard tissue ) was significantly smaller skull than older male adults ( identifiable because of the high loss of tooth structure ). It was concluded that the increase in size in the male Paranthropus robustus lasted until well after puberty. This observation was interpreted with reference to recent primates as a result of high social competition among the males, which is frequently observed in extant species, in turn, then, if a male dominated a group of females ( " harem " ) and keep other males from this group tries.

The males had a 2011 published study, from birth largely sedentary, while female migrant workers arriving from other populations, which was interpreted as an indication of exogamy; female exogamy and male site fidelity is also available in chimpanzees, while moving with the gorillas males and females after puberty alike in other populations.