Fossil Hominids: Type Specimens

Under the formal rules for naming species, each species must have a type specimen. The 'type description' of a species describes the type specimen, and the similarities to and differences from closely related species. Another fossil belongs to the same species if and only if it belongs to the same species as the type specimen. Obviously this is a subjective assessment, but this rule ensures that all scientists are at least using the same criteria when trying to allocate specimens to species. When scientific thinking about the classification of specimens changes, there are complicated rules which determine how specimens should be allocated to species.

If two type specimens are later determined to belong to the same species, then the first one named takes priority. For example, when it was decided that the 2nd known australopithecine fossil, assigned to Plesianthropus transvaalensis, actually belonged to the same species as the first, that name became invalid and all Plesianthropus fossils were reassigned to Australopithecus africanus.

If it is decided that the fossils previously assigned to a species actually belong to two different species, then the type specimen and any other specimens belonging to the same species as it keep the old name. The other fossils will take the name of whichever specimen among them is first used as a type specimen for a new species definition. An example is Homo habilis (type specimen OH 7); the species Homo rudolfensis, with type specimen ER 1470, consists of fossils formerly assigned to habilis.

Homo habilis is a controversial species, with much disagreement over which specimens belong in habilis, and which do not. A number of scientists now use the name H. rudolfensis to refer to ER 1470 and some similar fossils. The smaller habilis-like specimens such as ER 1813 and ER 1805 are variously assigned to habilis, H. ergaster, or to another as yet unnamed species. The name H. microcranous has been proposed for ER 1813, but is virtually never used. Wood and Collard (1999) have argued on theoretical grounds that H. habilis and H. rudolfensis should be moved into the genus Australopithecus. The latest development in this debate is the discovery of OH 65, a fossil jaw from Olduvai Gorge.

It has been proposed that the names Homo heidelbergensis and Homo neanderthalensis should be restored as species names for archaic Homo sapiens and the Neandertals. Recent claims of genetic and anatomical differences between modern humans and Neandertals have added support to a species status for Homo neanderthalensis. (Krings et al. 1997; Hublin et al. 1996; Tattersall and Schwartz 1996)

Java Man (Pithecanthropus erectus) and Peking Man (Sinanthropus pekinensis) were originally assigned not only to different species, but different genera from Homo sapiens. Scientists such as Boule who considered them in the same genus but not the same species would sink Sinanthropus as a genus and call Peking Man Pithecanthropus pekinensis. Most scientists soon decided they were in the same species, so the Peking Man specimens were reassigned to P. erectus because that name had priority over S. pekinensis. Later, when it was decided that P. erectus was in the same genus as Homo sapiens, the genus name Pithecanthropus was sunk and the specific name erectus was kept, so the species became Homo erectus.

There is no central authority which proclaims that, for example, Homo ergaster is henceforth a valid species. Instead, the fate of a species name depends on the extent to which scientists accept the claim of its namers that it a valid species distinguishable from all others. Many of the following species names are not used in these pages, either because they are rarely used, or are so new that there is as yet no consensus on their validity.

Where two species names are given, the first is the one which was given by the original namer of the fossil, and the second name is the one by which it is usually known now. This often occurs when the genus name originally assigned is rejected and the fossil is placed in another genus.

For anyone interested in the naming and classification of hominids, an indispensable reference is Naming our Ancestors (Meikle and Parker, 1994). This useful book contains an introduction to the terms and principles of taxonomy, reprints of 15 sources in which hominid species were first named, and reprints of four papers which have been very influential in hominid taxonomy.

Species Type Specimen Named By
Sahelanthropus tchadensis TM 266-01-060-1 Brunet et al. 2002
Orrorin tugenensis BAR 1000'00 Senut et al. 2001
Ardipithecus kadabba ALA-VP 2/10 Haile-Selassie 2001
Australopithecus ramidus
Ardipithecus ramidus
ARA-VP 6/1 White et al. 1994
Australopithecus anamensis KP 29281 M. Leakey et al. 1995
Australopithecus afarensis LH 4 Johanson et al. 1978
Homo antiquus AL 288-1 Ferguson 1984
Australopithecus bahrelghazali KT 12/H1 Brunet et al. 1996
Kenyanthropus platyops KNM-WT 40000 M. Leakey et al. 2001
Australopithecus africanus Taung Dart 1925
Australopithecus garhi BOU-VP-12/130 Asfaw et al. 1999
Paraustralopithecus aethiopicus
Australopithecus aethiopicus
Omo 18 Arambourg & Coppens 1968
Paranthropus robustus
Australopithecus robustus
TM 1517 Broom 1938
Australopithecus walkeri KNM-WT 17000 Ferguson 1989
Australopithecus sediba MH1 Berger et al. 2010
Zinjanthropus boisei
Australopithecus boisei
OH 5 L. Leakey 1959
Paranthropus crassidens
Australopithecus crassidens
SK 6 Broom 1949
Homo antiquus praegens
Australopithecus praegens
KNM-T1 13150 Ferguson 1989
Homo habilis OH 7 L. Leakey et al. 1964
Homo louisleakeyi OH 9 Kretzoi 1984
Pithecanthropus rudolfensis
Homo rudolfensis
KNM-ER 1470 Alexeev 1986
Homo microcranous KNM-ER 1813 Ferguson 1995
Homo gautengensis Stw-53 Curnoe 2010
Homo georgicus D2600 Gabunia et al. 2002
Homo ergaster KNM-ER 992 Groves & Mazak 1975
Pithecanthropus erectus
Homo erectus
Trinil 2 Dubois 1894
Homo cepranensis Ceprano Mallegni et al. 2003
Homo antecessor ATD6-5 Bermudez de Castro et al. 1997
Homo heidelbergensis Mauer 1 Schoetensack 1908
Homo rhodesiensis Kabwe Woodward 1921
Homo helmei Florisbad Dreyer 1935
Homo neanderthalensis Neandertal 1 King 1864
Homo floresiensis LB1 Brown et al. 2004
Homo sapiens - Linnaeus 1758

References

Meikle W.E. and Parker S.T. (1994): Naming our Ancestors: an anthology of hominid taxonomy. Prospect Heights, Illinois: Waveland Press.


International Code of Zoological Nomenclature

Curiosities of Biological Nomenclature, by Mark Isaak


This page is part of the Fossil Hominids FAQ at the talk.origins Archive.

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