Human taxonomy is the classification of the human species within zoological taxonomy. The systematic

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

, ''

Homo ''Homo'' () is a genus of great ape (family Hominidae) that emerged from the genus ''Australopithecus'' and encompasses only a single extant species, ''Homo sapiens'' (modern humans), along with a number of extinct species (collectively called ...

'', is designed to include both anatomically modern humans and extinct varieties of

archaic humans ''Homo'' () is a genus of great ape (family Hominidae) that emerged from the genus ''Australopithecus'' and encompasses only a single extant species, ''Homo sapiens'' (modern humans), along with a number of extinct species (collectively calle ...

. Current humans are classified as subspecies to ''Homo'', differentiated, according to some, from the direct ancestor, '' Homo sapiens idaltu'' (with some other research instead classifying ''idaltu'' and current humans as belonging to the same subspecies). Since the introduction of systematic names in the 18th century, knowledge of

human evolution ''Homo sapiens'' is a distinct species of the hominid family of primates, which also includes all the great apes. Over their evolutionary history, humans gradually developed traits such as Human skeletal changes due to bipedalism, bipedalism, de ...

has increased significantly, and a number of intermediate taxa have been proposed in the 20th and early 21st centuries. The most widely accepted taxonomy grouping takes the genus ''

'' as originating between two and three million years ago, divided into at least two species, archaic ''

Homo erectus ''Homo erectus'' ( ) is an extinction, extinct species of Homo, archaic human from the Pleistocene, spanning nearly 2 million years. It is the first human species to evolve a humanlike body plan and human gait, gait, to early expansions of h ...

'' and modern ''

Homo sapiens Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

'', with about a dozen further suggestions for species without universal recognition. The genus ''Homo'' is placed in the

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...

Hominini The Hominini (hominins) form a Tribe (biology), taxonomic tribe of the subfamily Homininae (hominines). They comprise two extant genera: ''Homo'' (humans) and ''Pan (genus), Pan'' (chimpanzees and bonobos), and in standard usage exclude the gen ...

alongside '' Pan'' (chimpanzees). The two genera are estimated to have diverged over an extended time of hybridization, spanning roughly 10 to 6 million years ago, with possible admixture as late as 4 million years ago. A subtribe of uncertain validity, grouping archaic "pre-human" or "para-human" species younger than the ''Homo''-''Pan'' split, is '' Australopithecina'' (proposed in 1939). A proposal by Wood and Richmond (2000) would introduce Hominina as a subtribe alongside Australopithecina, with ''Homo'' the only known genus within Hominina. Alternatively, following Cela-Conde and Ayala (2003), the "pre-human" or "proto-human" genera of ''Australopithecus'', ''Ardipithecus'', ''Praeanthropus'', and possibly ''Sahelanthropus'', may be placed on equal footing alongside the genus ''Homo''. An even more extreme view rejects the division of ''Pan'' and ''Homo'' as separate genera, which based on the Principle of Priority would imply the reclassification of chimpanzees as ''Homo paniscus'' (or similar). Categorizing humans based on phenotypes is a socially controversial subject. Biologists originally classified races as

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

, but contemporary anthropologists reject the concept of race as a useful tool to understanding humanity, and instead view humanity as a complex, interrelated genetic continuum. Taxonomy of the hominins continues to evolve.

History

Human taxonomy on one hand involves the placement of humans within the taxonomy of the hominids (great apes), and on the other the division of archaic and modern humans into

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

and, if applicable,

. Modern zoological taxonomy was developed by

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

during the 1730s to 1750s. He was the first to develop the idea that, like other biological entities, groups of people could too share taxonomic classifications. He named the human species as ''

'' in 1758, as the only member species of the genus ''Homo'', divided into several subspecies corresponding to the great races. The

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

noun '' homō'' (genitive ''hominis'') means "human being". The systematic name

Hominidae The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic Family (biology), family of primates that includes eight Neontology#Extant taxa versus extinct taxa, extant species in four Genus, genera: ''Orangutan ...

for the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of the great apes was introduced by

John Edward Gray John Edward Gray (12 February 1800 – 7 March 1875) was a British zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray (1766–1828). The same is used for a z ...

(1825). Gray also supplied

as the name of the

including both chimpanzees (genus '' Pan'') and humans (genus ''Homo''). The discovery of the first extinct archaic human species from the fossil record dates to the mid 19th century: ''

Homo neanderthalensis Neanderthals ( ; ''Homo neanderthalensis'' or sometimes ''H. sapiens neanderthalensis'') are an extinct group of archaic humans who inhabited Europe and Western and Central Asia during the Middle to Late Pleistocene. Neanderthal extinctio ...

'', classified in 1864. Since then, a number of other archaic species have been named, but there is no universal consensus as to their exact number. After the discovery of ''H. neanderthalensis'', which even if "archaic" is recognizable as clearly human, late 19th to early 20th century anthropology for a time was occupied with finding the supposedly " missing link" between ''Homo'' and ''Pan''. The " Piltdown Man" hoax of 1912 was the fraudulent presentation of such a transitional species. Since the mid-20th century, knowledge of the development of Hominini has become much more detailed, and taxonomical terminology has been altered a number of times to reflect this. The introduction of ''

Australopithecus ''Australopithecus'' (, ; or (, ) is a genus of early hominins that existed in Africa during the Pliocene and Early Pleistocene. The genera ''Homo'' (which includes modern humans), ''Paranthropus'', and ''Kenyanthropus'' evolved from some ''Aus ...

'' as a third genus, alongside ''Homo'' and ''Pan'', in the tribe Hominini is due to Raymond Dart (1925). Australopithecina as a subtribe containing ''Australopithecus'' as well as '' Paranthropus'' ( Broom 1938) is a proposal by Gregory & Hellman (1939). More recently proposed additions to the Australopithecina subtribe include '' Ardipithecus'' (1995) and '' Kenyanthropus'' (2001). The position of '' Sahelanthropus'' (2002) relative to Australopithecina within Hominini is unclear. Cela-Conde and Ayala (2003) propose the recognition of ''Australopithecus'', ''Ardipithecus'', ''Praeanthropus'', and ''Sahelanthropus'' (the latter ''incertae sedis'') as separate genera. Other proposed genera, now mostly considered part of ''Homo'', include: '' Pithecanthropus'' (Dubois, 1894), '' Protanthropus'' (Haeckel, 1895), '' Sinanthropus'' (Black, 1927), '' Cyphanthropus'' (Pycraft, 1928) '' Africanthropus'' (Dreyer, 1935), '' Telanthropus'' (Broom & Anderson 1949), '' Atlanthropus'' (Arambourg, 1954), '' Tchadanthropus'' (Coppens, 1965). The genus ''Homo'' has been taken to originate some two million years ago, since the discovery of stone tools in Olduvai Gorge,

Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...

, in the 1960s. '' Homo habilis'' (Leakey ''et al.'', 1964) would be the first "human" species (member of genus ''Homo'') by definition, its type specimen being the OH 7 fossils. However, the discovery of more fossils of this type has opened up the debate on the delineation of ''H. habilis'' from ''Australopithecus''. Especially, the LD 350-1 jawbone fossil discovered in 2013, dated to 2.8 Mya, has been argued as being transitional between the two. It is also disputed whether ''H. habilis'' was the first hominin to use stone tools, as '' Australopithecus garhi'', dated to c. 2.5 Mya, has been found along with stone tool implements. Fossil KNM-ER 1470 (discovered in 1972, designated ''Pithecanthropus rudolfensis'' by Alekseyev 1978) is now seen as either a third early species of ''Homo'' (alongside ''H. habilis'' and ''H. erectus'') at about 2 million years ago, or alternatively as transitional between ''Australopithecus'' and ''Homo''. Wood and Richmond (2000) proposed that Gray's tribe

("hominins") be designated as comprising all species after the chimpanzee–human last common ancestor by definition, to the inclusion of Australopithecines and other possible pre-human or para-human species (such as '' Ardipithecus'' and '' Sahelanthropus'') not known in Gray's time. In this suggestion, the new subtribe of Hominina was to be designated as including the genus ''Homo'' exclusively, so that Hominini would have two subtribes, Australopithecina and Hominina, with the only known genus in Hominina being ''Homo''. '' Orrorin'' (2001) has been proposed as a possible ancestor of Hominina but not Australopithecina. Designations alternative to Hominina have been proposed: Australopithecinae (Gregory & Hellman 1939) and Preanthropinae (Cela-Conde & Altaba 2002).

Species

At least a dozen species of ''Homo'' other than ''Homo sapiens'' have been proposed, with varying degrees of consensus. Most other proposed species are proposed as alternatively belonging to either ''Homo erectus'' or ''Homo sapiens'' as a subspecies. This concerns '' Homo ergaster'' in particular. One proposal divides ''Homo erectus'' into an African and an Asian variety; the African is ''Homo ergaster,'' and the Asian is ''Homo erectus sensu stricto.'' (Inclusion of ''Homo ergaster'' with Asian ''Homo erectus'' is ''Homo erectus sensu lato.'') There appears to be a recent trend, with the availability of ever more difficult-to-classify fossils such as the Dmanisi skulls (2013) or '' Homo naledi'' fossils (2015) to subsume all archaic varieties under ''Homo erectus''.

Subspecies

''Homo sapiens'' subspecies

The recognition or nonrecognition of

of ''Homo sapiens'' has a complicated history. The rank of subspecies in zoology is introduced for convenience, and not by objective criteria, based on pragmatic consideration of factors such as geographic isolation and

sexual selection Sexual selection is a mechanism of evolution in which members of one sex mate choice, choose mates of the other sex to mating, mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex ...

. The informal taxonomic rank of race is variously considered equivalent or subordinate to the rank of subspecies, and the division of anatomically modern humans (''H. sapiens'') into subspecies is closely tied to the recognition of major racial groupings based on human genetic variation. A subspecies cannot be recognized independently: a species will either be recognized as having no subspecies at all or at least two (including any that are extinct). Therefore, the designation of an extant subspecies ''Homo sapiens sapiens'' only makes sense if at least one other subspecies is recognized. ''H. s. sapiens'' is attributed to "Linnaeus (1758)" by the taxonomic Principle of Coordination. During the 19th to mid-20th century, it was common practice to classify the major divisions of extant ''H. sapiens'' as subspecies, following Linnaeus (1758), who had recognized ''H. s. americanus'', ''H. s. europaeus'', ''H. s. asiaticus'' and ''H. s. afer'' as grouping the native populations of the

Americas The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America.''Webster's New World College Dictionary'', 2010 by Wiley Publishing, Inc., Cleveland, Ohio. When viewed as a sing ...

, West Eurasia,

East Asia East Asia is a geocultural region of Asia. It includes China, Japan, Mongolia, North Korea, South Korea, and Taiwan, plus two special administrative regions of China, Hong Kong and Macau. The economies of Economy of China, China, Economy of Ja ...

and

Sub-Saharan Africa Sub-Saharan Africa is the area and regions of the continent of Africa that lie south of the Sahara. These include Central Africa, East Africa, Southern Africa, and West Africa. Geopolitically, in addition to the list of sovereign states and ...

, respectively. Linnaeus also included ''H. s. ferus'', for the "wild" form which he identified with feral children, and two other "wild" forms for reported specimens now considered very dubious (see cryptozoology), ''H. s. monstrosus'' and ''H. s. troglodytes''. There were variations and additions to the categories of Linnaeus, such as ''H. s. tasmanianus'' for the native population of Australia. Bory de St. Vincent in his ''Essai sur l'Homme'' (1825) extended Linnaeus's "

racial Race is a categorization of humans based on shared physical or social qualities into groups generally viewed as distinct within a given society. The term came into common usage during the 16th century, when it was used to refer to groups of va ...

" categories to as many as fifteen: ''Leiotrichi'' (" smooth-haired"): '' japeticus'' (with subraces), '' arabicus'', '' iranicus'', '' indicus'', '' sinicus'', '' hyperboreus'', '' neptunianus'', '' australasicus'', '' columbicus'', '' americanus'', '' patagonicus''; ''Oulotrichi'' (" crisp-haired"): '' aethiopicus'', '' cafer'', '' hottentotus'', '' melaninus''. Similarly, Georges Vacher de Lapouge (1899) also had categories based on race, such as ''priscus'', ''spelaeus'' (etc.). '' Homo sapiens neanderthalensis'' was proposed by King (1864) as an alternative to ''Homo neanderthalensis''. There have been "taxonomic wars" over whether Neanderthals were a separate species since their discovery in the 1860s. Pääbo (2014) frames this as a debate that is unresolvable in principle, "since there is no definition of species perfectly describing the case." Louis Lartet (1869) proposed '' Homo sapiens fossilis'' based on the Cro-Magnon fossils. There are a number of proposals of extinct varieties of ''Homo sapiens'' made in the 20th century. Many of the original proposals were not using explicit trinomial nomenclature, even though they are still cited as valid

synonyms A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''H. sapiens'' by Wilson & Reeder (2005). These include: '' Homo grimaldii'' (Lapouge, 1906), '' Homo aurignacensis hauseri'' (Klaatsch & Hauser, 1910), ''Notanthropus eurafricanus'' (Sergi, 1911), ''Homo fossilis ''infrasp.'' proto-aethiopicus'' (Giuffrida-Ruggeri, 1915), '' Telanthropus capensis'' (Broom, 1917), '' Homo wadjakensis'' (Dubois, 1921), '' Homo sapiens cro-magnonensis, Homo sapiens grimaldiensis'' (Gregory, 1921), ''Homo drennani'' (Kleinschmidt, 1931), ''Homo galilensis'' (Joleaud, 1931) = ''Paleanthropus palestinus'' (McCown & Keith, 1932). Rightmire (1983) proposed '' Homo sapiens rhodesiensis''. After World War II, the practice of dividing extant populations of ''Homo sapiens'' into subspecies declined. An early authority explicitly avoiding the division of ''H. sapiens'' into subspecies was '' Grzimeks Tierleben'', published 1967–1972. A late example of an academic authority proposing that the human racial groups should be considered taxonomical subspecies is John Baker (1974). The trinomial nomenclature ''Homo sapiens sapiens'' became popular for "modern humans" in the context of Neanderthals being considered a subspecies of ''H. sapiens'' in the second half of the 20th century. Derived from the convention, widespread in the 1980s, of considering two subspecies, ''H. s. neanderthalensis'' and ''H. s. sapiens'', the explicit claim that "''H. s. sapiens'' is the only extant human subspecies" appears in the early 1990s. Since the 2000s, the extinct '' Homo sapiens idaltu'' (White ''et al.'', 2003) has gained wide recognition as a subspecies of ''Homo sapiens'', but even in this case there is a dissenting view arguing that "the skulls may not be distinctive enough to warrant a new subspecies name". '' H. s. neanderthalensis'' and '' H. s. rhodesiensis'' continue to be considered separate species by some authorities, but the 2010s discovery of genetic evidence of archaic human admixture with modern humans has reopened the details of taxonomy of archaic humans.

''Homo erectus'' subspecies

'' since its introduction in 1892 has been divided into numerous subspecies, many of them formerly considered individual species of ''Homo''. None of these subspecies have universal consensus among paleontologists. * '' Homo erectus erectus'' ( Java Man) (1970s)In the 1970s a tendency developed to regard the Javanese variety of ''H. erectus'' as a subspecies, ''Homo erectus erectus'', with the Chinese variety being referred to as ''Homo erectus pekinensis''. See: * '' Homo erectus yuanmouensis'' ( Yuanmou Man) (Li et al., 1977) * '' Homo erectus lantianensis'' ( Lantian Man) (Woo Ju-Kang, 1964) * '' Homo erectus nankinensis'' ( Nanjing Man) (1993) * '' Homo erectus pekinensis'' ( Peking Man) (1970s) * '' Homo erectus palaeojavanicus'' ( Meganthropus) (Tyler, 2001) * '' Homo erectus soloensis'' ( Solo Man) (Oppenoorth, 1932) * '' Homo erectus tautavelensis'' ( Tautavel Man) (de Lumley and de Lumley, 1971) * '' Homo erectus georgicus'' (1991) * '' Homo erectus bilzingslebenensis'' (Vlček, 2002)Emanuel Vlček: ''Der fossile Mensch von Bilzingsleben'' (= ''Bilzingsleben. Bd. 6'' = ''Beiträge zur Ur- und Frühgeschichte Mitteleuropas'' 35). Beier & Beran, Langenweißbach 2002.

Footnotes

References

{{Taxonbar, from=Q17146890

Taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...