Australopithecine
Encyclopedia
The term australopithecine refers generally to any species in the related genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

  Australopithecus
Australopithecus
Australopithecus is a genus of hominids that is now extinct. From the evidence gathered by palaeontologists and archaeologists, it appears that the Australopithecus genus evolved in eastern Africa around 4 million years ago before spreading throughout the continent and eventually becoming extinct...

or Paranthropus
Paranthropus
The robust australopithecines, members of the extinct hominin genus Paranthropus , were bipedal hominids that probably descended from the gracile australopithecine hominids...

. These species occurred in the Plio-Pleistocene
Plio-Pleistocene
The term Plio-Pleistocene refers to the geological period more recent than circa 5 million years ago, incorporating both the formally defined epochs of the Pliocene and the Pleistocene...

 era, and were bipedal and dentally similar to humans, but with a brain size not much larger than modern apes, lacking the encephalization
Encephalization
Encephalization is defined as the amount of brain mass exceeding that related to an animal's total body mass. Quantifying an animal's encephalization has been argued to be directly related to that animal's level of intelligence. Aristotle wrote in 335 B.C...

 characteristics of the genus Homo
Homo
Homo may refer to:*the Greek prefix ὅμο-, meaning "the same"*the Latin for man, human being*Homo, the taxonomical genus including modern humans...

.

They are classified within the Hominina
Hominina
The more anthropomorphic primates of the Hominini tribe are placed in the Hominina subtribe. Referred to as hominans, they are characterized by the evolution of an increasingly erect bipedal locomotion. The only extant species is Homo sapiens...

 subtribe of the Hominini
Hominini
Hominini is the tribe of Homininae that comprises Homo, and the two species of the genus Pan , their ancestors, and the extinct lineages of their common ancestor . Members of the tribe are called hominins...

 tribe
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...

. They appeared in the Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...

:
  • Australopithecus, appeared about 4 million years ago;
  • Paranthropus, appeared about 2.7 million years ago.


When used alone, the term refers to both genera together. Australopithecus is sometimes referred to as the "gracile (slender) australopithecines", while Paranthropus are also called the "robust australopithecines".

A likely ancestor of the Australopithecines is the genus Ardipithecus
Ardipithecus
Ardipithecus is a very early hominin genus. Two species are described in the literature: A. ramidus, which lived about 4.4 million years ago during the early Pliocene, and A. kadabba, dated to approximately 5.6 million years ago ....

genus, which lived in East Africa. The Homo
Homo (genus)
Homo is the genus that includes modern humans and species closely related to them. The genus is estimated to be about 2.3 to 2.4 million years old, evolving from australopithecine ancestors with the appearance of Homo habilis....

genus (human
Human
Humans are the only living species in the Homo genus...

s, appear about 2.4 million years ago with Homo habilis
Homo habilis
Homo habilis is a species of the genus Homo, which lived from approximately at the beginning of the Pleistocene period. The discovery and description of this species is credited to both Mary and Louis Leakey, who found fossils in Tanzania, East Africa, between 1962 and 1964. Homo habilis Homo...

) appear to be descended from australopithecine ancestors, more precisely from Kenyanthropus platyops
Kenyanthropus platyops
Kenyanthropus platyops is a 3.5 to 3.2 million year old hominin fossil that was discovered in Lake Turkana, Kenya in 1999 by Justus Erus, who was part of Meave Leakey's team...

branching off Australopithecus some 3.5 million years ago. An alternative possibility is the derivation of Homo directly from Ardipithecus with an as yet undiscovered link connecting Ardipithecus and Homo habilis existing in parallel to the Australopithecines in the period 4 to 2.5 million years ago.

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