Australopithecus garhi

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Australopithecus garhi
Skull reconstruction

Skull reconstruction

Temporal occurrence
Pliocene
by 2.5 million years
Locations
Systematics
Human (Hominoidea)
Apes (Hominidae)
Homininae
Hominini
Australopithecus
Australopithecus garhi
Scientific name
Australopithecus garhi
Asfaw et al., 1999

Australopithecus garhi is a species of the extinct genus Australopithecus thatlived inwhat is now Ethiopia about 2.5 million years ago. Itis not clear how close Australopithecus garhi is to the direct ancestors of the genus Homo and thus to humans .

Naming

Australopithecus is an artificial word . The name of the genus is derived from Latin australis ("southern") and Greek πίθηκος, old Gr. pronounced píthēkos ("monkey"). The epithet garhi comes from the Afar language and means "astonishment, surprise". Australopithecus garhi means roughly "the surprising southern monkey".

Initial description

The first description of Australopithecus garhi was published in 1999 by a group of paleontologists led by Berhane Asfaw and Tim White . The holotype of Australopithecus garhi is a fragmentarily preserved skull with relatively large molars (inventory number BOU-VP-12/130), which was created on November 20, 1997 by Yohannes Haile-Selassie near Aramis in the Afar triangle , west of today's Awash on the eastern edge of the Bouri Peninsula, was discovered. Large parts of the frontal bone and parietal bone as well as the upper jaw with almost complete dentition are preserved. The type specimen is kept in the National Museum of Ethiopia in Addis Ababa .

In the first description of the species, further fossils from the same region were included, including further skull fragments, humerus bones , finger bones and a toothed lower jaw (BOU-VP-17/1). Various finds of hominine fossils of the same age from 1990 and 1996 to 1998 were also mentioned . These finds indicate individuals who had a human-like ratio of thigh to lower leg length and an ape-like ratio of upper arm length to forearm length. The assignment of these bone finds to the so-called "graceful Australopithecines" - to which Australopithecus anamensis , Australopithecus afarensis , and Australopithecus africanus are counted - was regarded as certain, but their affiliation to a certain species was left open. Since the association of these bone finds with the type of specimen is likely, but not clearly confirmed, the authors based their first description exclusively on the skull BOU-VP-12/130.

The internal volume of the skull was given in the first description as about 450 cm 3 ; For comparison: a chimpanzee brain is around 400 cm 3 , that of modern humans around 1400 cm 3 . The layers of earth from which the skull had been exposed by natural erosion were dated to an age of 2.5 million years using the argon-argon method .

Habitat

The habitat of Australopithecus garhi was described in a study published parallel to the first description. According to this, 2.5 million years ago there was a landscape in the Afar region that consisted of savannahs and freshwater lakes. The study also mentions that clues for the use of the first stone tools were discovered in the strata of the earth from which the bones were recovered . It is unclear whether these clues - presumed cutting marks on animal bones - can be linked to Australopithecus garhi .

classification

According to the authors of the first description, the large molars and the relatively small brain volume speak in favor of classifying the fossils in the Australopithecus taxon . In the first description it is also said that Australopithecus garhi descends from Australopithecus afarensis and is a possible ancestor of the earliest representatives of the genus Homo ; the oldest fossil assigned to the genus Homo so far , the lower jaw of a Homo rudolfensis discovered by Friedemann Schrenk (inventory number UR 501 ), was dated to an age of 2.4 million years. The authors point out, however, that Australopithecus garhi is so close in time and physique to the early representatives of the genus Homo that - if more finds are made - the species could even be assigned to Homo .

Possibly the fossil BOU-VP-12/130 - the type specimen of Australopithecus garhi - belongs to the same group of forms as the fossils related to Paranthropus aethiopicus ; common features of the discovered lower jaw indicate this. Should this be the case, the fossils identified as Australopithecus garhi would have to be renamed and referred to as Paranthropus aethiopicus .

It was also criticized that the range of variation of Australopithecus africanus is so great that there are no characteristics "which unequivocally distinguish A. africanus from A. garhi ." The distance of both species from 40 degrees of latitude speaks on the one hand for the classification of the respective finds in its own kind; on the other hand, Australopithecus africanus was "possibly as widespread as is typical of the various baboon species ."

See also

Web links

Individual evidence

  1. ↑ Berhane Asfaw , Tim White , C. Owen Lovejoy , Bruce Latimer, Scott Simpson, Gen Suwa: Australopithecus garhi: A New Species of Hominid From Ethiopia. In: Science . Volume 284, 1999, pp. 629–635, doi : 10.1126 / science.284.5414.629 and as full text ( Memento from May 22, 2009 in the Internet Archive )
  2. ↑ In the study by Asfaw et al. the inventory number was accidentally identified as ARA-VP-12/130; ARA stands for Aramis, BOU for the location Bouri.
  3. ^ Jean de Heinzelin et al .: Environment and Behavior of 2.5-Million-Year-Old Bouri Hominids. Science 284 of April 23, 1999, pp. 625–629, doi : 10.1126 / science.284.5414.625 , compare the overview here ( Memento from January 20, 2009 in the Internet Archive ) and here
  4. ↑ Bernard Wood , Nicholas Lonergan: The hominin fossil record: taxa, grades and clades. In: Journal of Anatomy . Volume 212, No. 4, 2008, p. 359, DOI: 10.1111 / j.1469-7580.2008.00871.x , full text (PDF; 292 kB) ( Memento from October 29, 2013 in the Internet Archive )
  5. ↑ Gary J. Sawyer, Viktor Deak: The Long Way to Man. Life pictures from 7 million years of evolution. Spektrum Akademischer Verlag, Heidelberg 2008, ISBN 978-3827419156 , p. 58.