Australopithecus africanus

Original of the skull of an A. africanus ( "Mrs. Ples " ) in the Transvaal Museum in Pretoria

• South Africa

Australopithecus africanus is a species of the extinct genus Australopithecus. Fossils, Australopithecus africanus were assigned mostly come from around 3.0 million and 2.5 million year old layers Fund in South Africa; However, some findings may be a little older, others a little younger.

From which precursor species Australopithecus africanus derived and how close he is to the immediate ancestors of man, is unclear. The species is often - in opposition to the so-called " robust australopithecines " - also known as gracile australopithecines.

Naming

Australopithecus africanus is the type species of the genus Australopithecus. The name is derived from the Latin australis, south ' and Greek πίθηκος ( altgr. pronounced) píthēkos, monkey '. The epithet refers to the locality africanus in Africa; Australopithecus africanus actually means " southern ape from Africa".

Physique

The foramen magnum of exclusively in South Africa discovered Australopithecus africanus, through which the rearmost part of the brain through the beginning of the spinal cord extends, is located below the skull, near the center of gravity. It can be concluded that Australopithecus africanus could walk upright. However, Australopithecus africanus had relatively long arms, so that his transition to the modern baboons could have been comparable, although it should have gone more frequently upright than this. From the relatively abundant skeletal remains could therefore be inferred that the individuals of this type, probably more often on trees were staying as other species of the genus Australopithecus. Australopithecus africanus also had relatively large molars, his skull had therefore relatively ape -like. However, the canines are substantially smaller than fossil and recent monkeys.

The brain volume is given in the literature with 400 to 500 cubic centimeters, which corresponds approximately to that of chimpanzees. The body size of adult individuals is estimated to be approximately 1.10 to 1.40 meters and her body weight 30 to 60 kg, with males were significantly larger than females. Associated finds suggest that Australopithecus africanus - like other australopithecines - " forested habitats " in transition preferred to savannas and " a close connection to the wide riparian zones of rivers and lakes," maintained.

One of the oldest human-like anatomical features, the shape of the anvil in the middle ear, which is already occupied for Australopithecus africanus ( the fossil Stw 255 from Sterkfontein ) and Paranthropus robustus and probably different from the shape of the anvil in chimpanzees already in their last common ancestor.

Diet and lifestyle

The compared to humans relatively large molars as an adaptation to a relatively hard plant food - interpreted - including at least temporarily, hard-shelled seeds. There was thus obtained a computer analysis of the fossils Sts 5 and Sts 52 a ( a well-preserved upper jaw ) that the teeth and the construction of the facial bones were likely similar to today's living cynomolgus monkeys withstand high pressure.

For Australopithecus africanus was further demonstrated by the nature of the teeth that he fed to more than 50 percent of their daily calorie intake of C3 plants and to a further significant proportion of C4 plants. This mainly consists of leaves, fruits and seeds food was - possibly depending on the season - supplemented by meat; this combination of plant and animal food differed Australopithecus africanus Paranthropus robustus probably both of which had significantly more specialized in tough plant foods, as well as of the early members of the genus Homo who consumed a higher proportion of meat.

Stone tools were not discovered in the fossil record of Australopithecus africanus -bearing strata.

The male individuals of Australopithecus africanus was 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.

Fund history

Holotype

Type specimen of Australopithecus africanus and thus also for the genus Australopithecus is the 1924 discovered the Taung Child. It was also the first piece of the Fund introduced in 1925 by Raymond Dart genus. Have been preserved of the facial skull with lower jaw and milk teeth, the forehead region, as well as a natural Schädelausguss. This fossil was (now South Africa) discovered and Raymond Dart passed, who named it in 1925 with the genus and species names of the newly formed him in the fall of 1924 by a quarry worker near the town of Taung in the then British Bechuanaland.

Further finds

After the assignment of the genus Australopithecus to the pre-humans for decades was controversial, could, among others, the discovery of the skull of Mrs. Ples ( possibly a "Mr. Ples " was ) confirm this assignment. The skull discovered at Sterkfontein is now dated to an age of about 2.1 million years, he is the youngest Fund for Australopithecus africanus.

The most complete skeleton that was in his first description assigned yet restrained " Australopithecus africanus or another early hominid species ," came from 1995, also in one of the Sterkfontein caves to light. It was given the inventory number CT 573 and nicknamed Little Foot, because in the beginning (1994 ) only four bones of the left foot had been discovered. 1997, by Ronald J. Clarke in the cave more bone and 1998 finally discovered a well-preserved skull. The bones are not yet fully exposed because of their concrete -like solid embedded in breccia. Very contradictory data have been published to date, which vary from 2.17 to 3.5 million years ago.

Some from 1936 discovered in Sterkfontein fossil finds, which are classified today as Australopithecus africanus, were first referred to as Plesianthropus transvaalensis ("Fast man from Transvaal "). This genus name chose Robert Broom, after he had in 1936 found the first early Hominini Fossil in Sterkfontein, because he assumed that it 'm close to the ancestors of man. The 1947 published discovery of Mrs Ples arranged Broom also Plesianthropus transvaalensis to. Ernst Mayr called this way in 1950, however, finds old as Homo transvaalensis. Some findings that are associated with today Australopithecus africanus, Raymond Dart had initially reported as Australopithecus prometheus, named after the Greek god Prometheus (the " Forward-thinking " ), who brought fire to the people; Dart had mistakenly concluded from charred bones in Makapansgat that early hominids already ruled the fire.

Apart from Sterkfontein Makapansgat is the most important locality of fossils of Australopithecus africanus, some teeth are from the Gladysvale Cave; from Taung is known only to the child's skull.