australopithecines

The australopithecines (), formally Australopithecina or Hominina, are generally any species in the related genera of ''Australopithecus'' and ''Paranthropus''. It may also include members of '' Kenyanthropus'', '' Ardipithecus'', and '' Praeanthropus''. The term comes from a former classification as members of a distinct subfamily, the Australopithecinae. They are classified within the Australopithecina subtribe of the Hominini tribe. These related species are sometimes collectively termed australopithecines, australopiths, or homininians. They are the extinct, close relatives of modern humans and, together with the extant genus ''Homo'', comprise the human clade. There is no general agreement to whether australopithecines are closest relatives of modern humans, as it has been argued that they are more closely related to extant African apes. Members of the human clade, i.e. the Hominini after the split from the chimpanzees, are called Hominina (''see Hominidae; terms "hominids" and hominins'').

While none of the groups normally directly assigned to this group survived, the australopithecines do not appear to be literally extinct (in the sense of having no living descendants) as the genera ''Kenyanthropus'', ''Paranthropus'', and ''Homo'' probably emerged as sisters of a late ''Australopithecus'' species such as '' A. africanus'' and/or '' A. sediba''.

The terms australopithecines, et. al., come from a former classification as members of a distinct subfamily, the Australopithecinae. Members of ''Australopithecus'' are sometimes referred to as the "gracile australopithecines", while ''Paranthropus'' are called the "robust australopithecines".

The australopithecines occurred in the Late Miocene sub-epoch and were bipedal, and they were dentally similar to humans, but with a brain size not much larger than that of modern non-human apes, with lesser encephalization than in the genus ''Homo''. Humans (genus ''Homo'') may have descended from australopithecine ancestors and the genera '' Ardipithecus'', '' Orrorin'', '' Sahelanthropus'', and '' Graecopithecus'' are the possible ancestors of the australopithecines.

Classification

Classification of subtribe Australopithecina according to .
*Australopithecina
**''Australopithecus''
***'' Australopithecus africanus''
***'' Australopithecus deyiremeda''
***'' Australopithecus garhi''
***'' Australopithecus sediba''
***''Australopithecus afarensis'' (=''Praeanthropus afarensis'')
***'' Australopithecus anamensis'' (=''Praeanthropus anamensis'')
***'' Australopithecus bahrelghazali'' (=''Praeanthropus bahrelghazali'')
**''Paranthropus''
***'' Paranthropus robustus''
***'' Paranthropus boisei''
***'' Paranthropus aethiopicus''
**'' Ardipithecus''
***'' Ardipithecus ramidus''
***'' Ardipithecus kadabba''
**'' Orrorin''
***'' Orrorin tugenensis''
**'' Sahelanthropus''
***'' Sahelanthropus tchadensis''

Phylogeny

Phylogeny of Hominina/Australopithecina according to Dembo ''et al''. (2016).

Physical characteristics

The post-cranial remains of australopithecines show they were adapted to bipedal locomotion, but did not walk identically to humans. They had a forearm to upper arm ratio similar to the ''Golden Ratio'' – greater than other hominins. They exhibited greater sexual dimorphism than members of ''Homo'' or '' Pan'' but less so than '' Gorilla'' or '' Pongo''. It is thought that they averaged heights of and weighed between . The brain size may have been 350 cc to 600 cc. The postcanines (the teeth behind the canines) were relatively large, and had more enamel compared to contemporary apes and humans, whereas the incisors and canines were relatively small, and there was little difference between the males' and females' canines compared to modern apes.

Relation to ''Homo''

Most scientists maintain that the genus ''Homo'' emerged in Africa within the australopithecines around two million years ago. However, there is no consensus on within which species:

Marc Verhaegen has argued that an australopithecine species could have also been ancestral to the genus '' Pan'' (i.e. chimpanzees).

Asian australopithecines

A minority view among palaeoanthropologists is that australopithecines moved outside Africa. One proponent of this theory is Jens Lorenz Franzen, formerly Head of Paleoanthropology at the Research Institute Senckenberg. Franzen argued that robust australopithecines had reached not only Indonesia, as '' Meganthropus'', but also China:

In 1957, an Early Pleistocene Chinese fossil tooth of unknown province was described as resembling '' P. robustus''. Three fossilized molars from Jianshi, China (Longgudong Cave) were later identified as belonging to an ''Australopithecus'' species. However further examination questioned this interpretation; Zhang (1984) argued the Jianshi teeth and unidentified tooth belong to ''H. erectus''. Liu ''et al''. (2010) also dispute the Jianshi–australopithecine link and argue the Jianshi molars fall within the range of ''Homo erectus'':

However, Wolpoff (1999) notes that in China "persistent claims of australopithecine or australopithecine-like remains continue".

See also

* ''Dawn of Humanity'' (2015 PBS film)
* Human taxonomy
* Human timeline

Notes

References

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External links

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Informative lecture on ''Australopithecines''

{{DEFAULTSORT:Australopithecine

Human evolution
Pliocene
Hominini