Homo habilis: Difference between revisions
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==Description== | ==Description== | ||
''H. habilis'' is complex to describe and there is considerable debate concerning which specimens are definitively placed into this species<ref name="Wood">, however, characters which are found in the holotype – OH-7 – from Olduvai Gorge in Tanzania, and traits found in other specimens generally considered to be included in the species are: <ref name="Phylogeny"/> | ''H. habilis'' is complex to describe and there is considerable debate concerning which specimens are definitively placed into this species<ref name="Wood"/>, however, characters which are found in the holotype – OH-7 – from Olduvai Gorge in Tanzania, and traits found in other specimens generally considered to be included in the species are: <ref name="Phylogeny"/> | ||
*Expanded cranial capacity over earlier australopithecines. | *Expanded cranial capacity over earlier australopithecines. | ||
*Reduced third premolar size and asymmetrical shape. | *Reduced third premolar size and asymmetrical shape. | ||
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*presence of a precision grip (possibly associated with tool use). | *presence of a precision grip (possibly associated with tool use). | ||
Based on the very fragmentary skeleton OH-62 from Olduvai Gorge in Tanzania it has been suggested that ''H. habilis'' had long arms and short legs. Recent evidence, however, suggests that these “ape-like” proportions may have been overestimated<ref name="Green">{{cite book|title= Limb proportions in ''Australopihtecus afarensis'' and ''Australopithecus africanus'' |accessdate=|author=D. Green et al.|authorlink= |coauthors= |date=2007 |format= |work= |publisher= J. Hum Evol. |pages= |language= |archiveurl= |archivedate= |quote= }}</ref>. | Based on the very fragmentary skeleton OH-62 from Olduvai Gorge in Tanzania it has been suggested that ''H. habilis'' had long arms and short legs. Recent evidence, however, suggests that these “ape-like” proportions may have been overestimated<ref name="Green">{{cite book|title= Limb proportions in ''[[Australopihtecus afarensis]]'' and ''[[Australopithecus africanus]]'' |accessdate=|author=D. Green et al.|authorlink= |coauthors= |date=2007 |format= |work= |publisher= J. Hum Evol. |pages= |language= |archiveurl= |archivedate= |quote= }}</ref>. | ||
==Taxonomic status== | ==Taxonomic status== | ||
Some researchers have recently suggested that fossils attributed to ''H. habilis'' would be better placed into the genus ''[[Australopithecus]]'' based in part upon certain morphological characters, the limited number of characters that separate it from earlier australopithecines and the perceived presence of other more derived members of the genus ''Homo'' present during the same temporal period<ref name="Wolpoff">{{cite book|title= Paleoanthropology |accessdate=|author=M. Wolpoff|authorlink= |coauthors= |date=1999|format= |work= |publisher= J. Hum Evol. |pages= |language= |archiveurl= |archivedate= |quote= }}</ref>. Whether species ''habilis'' remains in the genus ''Homo'' or in the genus ''Australopithecus'' has not been completely resolved<ref name="Wolpoff"/>. | Some researchers have recently suggested that fossils attributed to ''H. habilis'' would be better placed into the genus ''[[Australopithecus]]'' based in part upon certain morphological characters, the limited number of characters that separate it from earlier australopithecines and the perceived presence of other more derived members of the genus ''Homo'' present during the same temporal period<ref name="Wolpoff">{{cite book|title= Paleoanthropology |accessdate=|author=M. Wolpoff|authorlink= |coauthors= |date=1999|format= |work= |publisher= J. Hum Evol. |pages= |language= |archiveurl= |archivedate= |quote= }}</ref>. Whether species ''habilis'' remains in the genus ''Homo'' or in the genus ''Australopithecus'' has not been completely resolved<ref name="Wolpoff"/>. | ||
Revision as of 09:11, 11 September 2007
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| Homo habilis Leakey et al, 1964[1] |
Homo habilis is an enigmatic early hominin species found dominantly in East African fossil deposits dated to approximately 1.8 to 2 million years ago.
With a larger brain than the australopithecines (around 600 – 710cc), H. habilis, meaning “handy man”, was the first species of extinct hominin placed in the genus Homo[1][2].
History of Discovery
The first specimen was found by Mary Leakey at Olduvai Gorge in 1960.[2]With its rounder head, reduced prognathism, more human-like teeth and less pronounced brow ridges, it was interpreted as being considerably more “human-like” in appearance and thus possibly ancestral to H. erectus[3] Little is known about this species, in large part because there is little agreement as to exactly which fossils can be ascribed to it in both East and South Africa[4].
Description
H. habilis is complex to describe and there is considerable debate concerning which specimens are definitively placed into this species[4], however, characters which are found in the holotype – OH-7 – from Olduvai Gorge in Tanzania, and traits found in other specimens generally considered to be included in the species are: [3]
- Expanded cranial capacity over earlier australopithecines.
- Reduced third premolar size and asymmetrical shape.
- Reduced post-canine tooth size.
- presence of a precision grip (possibly associated with tool use).
Based on the very fragmentary skeleton OH-62 from Olduvai Gorge in Tanzania it has been suggested that H. habilis had long arms and short legs. Recent evidence, however, suggests that these “ape-like” proportions may have been overestimated[5].
Taxonomic status
Some researchers have recently suggested that fossils attributed to H. habilis would be better placed into the genus Australopithecus based in part upon certain morphological characters, the limited number of characters that separate it from earlier australopithecines and the perceived presence of other more derived members of the genus Homo present during the same temporal period[6]. Whether species habilis remains in the genus Homo or in the genus Australopithecus has not been completely resolved[6].
Language in "H. habilis"
It has been suggested that H. habilis had the capacity for complex language, but confirmation of this is difficult as it is based largely on poorly preserved endocasts (cast of the brain made by making an impression of the interior of the skull).
Occurrences
Fossil attributed to H. habilis have been found at Olduvai Gorge in Tanzania, as well as Koobi Fora in Kenya. H. habilis has been described from Sterkfontein in South Africa, though this identification has been questioned.
Temporal range
Its estimated time range in Africa is from just over 2 million years until about 1.5 million years when it apparently became extinct.
Tool making and use
H. habilis has long been associated with the crude Oldowan tool industry[1]. It is possible that the earliest stone tools in Africa at 2.5 million years of age in Ethiopia were produced by H. habilis, but again confirmation is difficult and there are several other early Homo species and even australopithecines that are temporally associated with these early tools.
Important Homo habilis fossils
- OH-7 – the holotype of H. habilis.
- OH-8 a nearly complete foot that has been bitten by a crocodile.
- OH-24 – nicknamed “Twiggy”
- Oh-62 – a partial skeleton from Olduvai Gorge, Tanzania.
- Stw 53 – a possible H. habilis skull from Sterkfontein, South Africa.
Homo habilis sites
Odluvai Gorge, Tanzania Koobi for a, Kenya Sterkfontein, South Africa (possible)
References
- ↑ 1.0 1.1 1.2 L.S.B. Leakey, Tobias, P.V. and Napier, J. (1964). A new species of genus Homo from Olduvai Gorge. Nature.
- ↑ 2.0 2.1 P.V. Tobias (1991). Olduvai Gorge Volume 4. The Skulls, Endocasts, and Teeth of Homo habilis. New York: Cambridge University Press.
- ↑ 3.0 3.1 C. David Kreger (2006). Homo habilis. Archeology.info.
- ↑ 4.0 4.1 B. Wood (1993). Early "Homo": How many species?" In Species, Species Concepts, and Primate Evolution, ed. by W.H. Kimbel, and L.B. Martin. Plenum Press.
- ↑ D. Green et al. (2007). Limb proportions in Australopihtecus afarensis and Australopithecus africanus. J. Hum Evol..
- ↑ 6.0 6.1 M. Wolpoff (1999). Paleoanthropology. J. Hum Evol..