View source for User:Cesiumfrog/Hominoid taxonomy

{{merge from|Hominidae|History of hominoid taxonomy}}
{{merge|Human taxonomy}}

[[File:Homo sapiens neanderthalensis.jpg|thumb|right|Skull of ''[[Homo neanderthalensis]]'']]
[[File:Sahelanthropus tchadensis - TM 266-01-060-1.jpg|thumb|right|Skull of ''[[Sahelanthropus tchadensis]]'', a candidate for being considered the earliest fossil hominin.]]
[[File:Male gorilla in SF zoo.jpg|thumb|right|[[Western gorilla]]]]

==Taxonomy (current)==
The current taxonomy for all species of apes is:

{{clade| style=font-size:75%;line-height:75%
|label1='''Hominoidea''' <!-- apes -->
|1={{clade 
 |label1='''Homininae''' <!-- great apes -->
 |1={{clade 
  |label1='''Hominidae''' <!-- african great apes -->
  |1={{clade 
   |label1=[[Gorilla|Gorillinae]] <!-- gorillas -->
   |1={{clade
    |label1=[[western gorilla|gorilla]]
    |1={{clade
     |1=[[Western lowland gorilla]]
     |2=[[Cross River gorilla]]
     }}
    |label2=[[eastern gorilla|beringei]]
    |2={{clade
     |1=[[Mountain gorilla]]
     |2=[[Eastern lowland gorilla]]
     }}
    }}
   |label2='''Homininae''' <!-- the 3 broadly-construed chimpanzees -->
   |2={{clade
    |label1='''Hominini''' <!-- proto-humans -->
    |1={{clade
     |label1=[[Australopithecine|Australopithecina]]
     |1={{clade
      |1=[[Ardipithecus]]†
      |2=[[Australopithecus]]†
      |3=[[Paranthropus]]†
      }}
     |label2='''Hominina''' <!-- Homo genus -->
     |2={{clade
      |1=[[Homo erectus]]†
      |2='''[[Homo sapiens]]'''
      }}
     }}
    |label2=[[chimpanzee|Pan]] <!-- chimpanzees -->
    |2={{clade
     |label1=troglodytes
     |1={{clade
      |1=[[Central chimpanzee]]
      |2=[[Western chimpanzee]]
      |3=[[Nigeria-Cameroon chimpanzee]]
      |4=[[Eastern chimpanzee]]
      }}
     |2=[[bonobo]] (pygmy chimpanzee)
     }}
    }}
   }}
  |label2=[[orangutan|Ponginae]] <!-- orangutans -->
  |2={{clade
   |label1=[[Bornean orangutan]]
   |1={{clade
    |1=pygmaeus
    |2=morio
    |3=wurmbii
    }}
   |2=[[Sumatran orangutan]]
   }}
  }}
 |label2=[[gibbon|Hylobatidae]] <!-- gibbons -->
 |2={{clade
  |label1=[[Hylobates]]
  |1={{clade
   |1=[[Lar gibbon]] or white-handed gibbon
   |2=[[Bornean white-bearded gibbon]]
   |3=[[Agile gibbon]] or black-handed gibbon
   |4=[[Müller's Bornean gibbon]] or grey gibbon
   |5=[[Silvery gibbon]]
   |6=[[Pileated gibbon]] or capped gibbon
   |7=[[Kloss's gibbon]] or Mentawai gibbon or bilou
   }}
  |label2=[[Hoolock]]
  |2={{clade
   |1=[[Western hoolock gibbon]]
   |2=[[Eastern hoolock gibbon]]
   }}
  |label3=[[Symphalangus]]
  |3=[[Siamang]]
  |label4=[[Nomascus]]
  |4={{clade
   |1=[[Black crested gibbon]]
   |2=[[Eastern black crested gibbon]]
   |3=[[Hainan black crested gibbon]]
   |4=[[Southern white-cheeked gibbon]]
   |5=[[White-cheeked crested gibbon]]
   |6=[[Yellow-cheeked gibbon]]
   }}
  }}
 }}
}}

==Terminology==
===Clades which include humans===
A major focus of hominoid taxonomy is the evolutionary history of humans, and hence on clades which contain ''Homo sapiens''.
====Hominina====
In the taxonomic classification of [[primates]] '''Hominina''' is sometimes used to describe a [[subtribe]] of the tribe [[Hominini]] which includes only the genus ''Homo''. Hominini in turn includes the [[australopithecine]]s and earlier upright walking primates such as ''[[Orrorin tugenensis]]'', ''[[Ardipithecus]]'' and ''[[Sahelanthropus]]''.<ref name=WoodRichmond/> Members are known as '''hominans''' or '''hominas'''
====Hominini====
'''Hominini''' is the [[tribe (biology)|tribe]] of [[Homininae]] that comprises ''[[homo (genus)|Homo]]'', and other members of the human clade after the split from the tribe [[Chimpanzee|Panini]] (chimpanzees).<ref name=Bradley2006>{{cite journal | author = Bradley, B.J. | year = 2006 | title = Reconstructing Phylogenies and Phenotypes: A Molecular View of Human Evolution | journal = Journal of Anatomy | volume = 212 | issue = 4 | pages = 337-353 | doi = 10.1111/j.1469-7580.2007.00840.x}}</ref><ref name=WoodRichmond>{{cite journal | author= Wood and Richmond. | year = 2000 | title =  Human evolution: taxonomy and paleobiology | journal = Journal of Anatomy  | volume = 197 | pages = 19–60 | pmid = 10999270 | last2= Richmond | first2= BG | pmc= 1468107 | doi=10.1046/j.1469-7580.2000.19710019.x}}</ref> Members of the tribe are called '''hominins''' (cf. [[Hominidae]], "hominids"). The [[subtribe]] [[Hominina]] is the "human" branch, including genus ''Homo''.  Researchers proposed the [[taxon]] Hominini on the basis of the idea that the least similar species of a [[trichotomy]] should be separated from the other two. Some earlier classification schemes include the genus ''[[Pan (genus)|Pan]]'' (chimpanzees) within the Hominini, but this classification is now rarely followed. 

Through [[DNA]] comparison, scientists believe the ''Pan''/''Homo'' divergence occurred between 5.4 and 6.3 million years ago, after an unusual process of [[speciation]] that ranged over 4 million years.<ref name=split>{{cite web | url =  | title = Human and chimp genomes reveal new twist on origin of species | accessdate = 2007-04-12 | date = 2006-05-17 | work = [ EurekAlert!/AAAS]}}</ref> Few fossil specimens on the ''Pan'' side of the split have been found, the first fossil chimpanzee discovery being published in 2005,<ref name=McBrearty>{{cite journal | author = McBrearty, Sally and Nina G. Jablonski | year = 2005 | title = First fossil chimpanzee | journal = Nature | volume = 437 | issue = 7055 | pages = 105–108 | doi = 10.1038/nature04008 | pmid = 16136135|bibcode = 2005Natur.437..105M }}</ref> dating to between 545 ± 3 kyr (thousand years) and 284 ± 12 kyr via [[Argon-argon dating]], from Kenya's East African Rift Valley. All of the extinct genera listed in the table to the right are ancestral to ''Homo'', or are offshoots of such. However, both ''[[Orrorin]]'' and ''[[Sahelanthropus]]'' existed around the time of the split, and so may be ancestral to all three extant species.

In the proposal of Mann and Weiss (1996),<ref name=Mann>{{cite journal | author = Mann, Alan and Mark Weiss | year = 1996 | title = Hominoid Phylogeny and Taxonomy: a consideration of the molecular and Fossil Evidence in an Historical Perspective | journal = Molecular Phylogenetics and Evolution | volume = 5 | issue = 1 | pages = 169–181 | doi = 10.1006/mpev.1996.0011 | pmid = 8673284}}</ref> the tribe Hominini includes ''Pan'' as well as ''Homo'', but within separate subtribes. ''Homo'' (and, by inference, all bipedal apes) is in the subtribe [[Hominina]], while ''Pan'' is in the subtribe Panina. Wood (2010) discusses the different views of this taxonomy.<ref name=Wood2010>{{cite journal | author = B. Wood | year = 2010 | title = Reconstructing human evolution: Achievements, challenges, and opportunities | journal = Proceedings of the National Academy of Sciences | volume = 107 | pages = 8902–8909 | doi = 10.1073/pnas.1001649107 | bibcode=2010PNAS..107.8902W}}</ref>
====Homininae====
{{POV|date=November 2011}}
'''Homininae''' is a subfamily of [[Hominidae]] that includes [[humans]], [[gorilla]]s, [[chimpanzee]]s, and some extinct relatives; it comprises all [[hominids]] that arose after the split from orangutans ([[Ponginae]]). Roughly, it is the African great apes. The Homininae [[cladogram]] has three main branches, which lead to gorillas, chimpanzees, and humans. There are several extant species of chimpanzees and gorillas, but only one human species remains, although several sub-species of ''Homo sapiens'' still existed 30,000 years ago. Organisms in this class are described as '''hominine''' or '''hominines'''.
====Hominidae====
The great apes, that is, orangutans, gorillas, chimpanzees and humans.
====Hominoidea====
Apes (gibbons and the great apes) including humans.
==History of classification==
{{See also|List of human evolution fossils}}
Until 1980, the family Hominidae contained only humans, with the [[great ape]]s in the family [[Pongidae]].<ref name=Goodman>{{cite book | author = M. Goodman | year = 1964 | chapter = Man’s place in the phylogeny of the primates as reflected in serum proteins | editor = S. L. Washburn | title = Classification and human evolution | publisher = Aldine, Chicago|pages = 204–234}}</ref> Later discoveries led to a revision of classification, with Hominidae uniting the great apes (now in the sub-family Ponginae) and humans (in the sub-family Homininae).<ref name=Goodman1>{{cite journal | journal = Annual Review of Anthropology | volume = 3 | pages = 203–228 | year = 1974 | doi =  10.1146/annurev.an.03.100174.001223 | title = Biochemical Evidence on Hominid Phylogeny | author = M. Goodman}}</ref> Further discoveries indicated that gorillas and chimpanzees are more closely related to humans than they are to orangutans, leading to their current placement in Homininae as well.<ref name=Goodman2>{{cite journal | journal = Journal of Molecular Evolution | year = 1990 | volume = 30 | pages = 260–266 | title = Primate evolution at the DNA level and a classification of hominoids | author = M. Goodman, D. A. Tagle, D. H. Fitch, W. Bailey, J. Czelusniak, B. F. Koop, P. Benson, J. L. Slightom | doi = 10.1007/BF02099995 | pmid = 2109087 | issue = 3}}</ref>

The subfamily Homininae can be further subdivided into three tribes, each with only a single living genus: [[Gorillini]] (gorillas), [[Chimpanzee|Panini]] (chimpanzees), and [[Hominini]] (humans and their extinct relatives). The early [[Late Miocene]] ''[[Nakalipithecus nakayamai]]'', described in 2007, and perhaps also its contemporary ''[[Ouranopithecus]]'', are [[basal (evolution)|basal]] members of this [[clade]], not assignable to any of the three extant tribes. They suggest that the Homininae tribes diverged not earlier than about 8 million years ago (see [[Human evolutionary genetics]]).

Today, chimpanzees and gorillas live in tropical forests with acid soils that rarely preserved as fossils. No fossil chimpanzees or gorillas have been reported. However, four chimpanzee teeth, about 500,000 years old, have recently been discovered in the rift valley,{{clarify|date=January 2012}}<!--where?--> where many fossils from the human lineage (hominins)<ref group="Note">A ''hominin'' is a member of the tribe Hominini, a ''hominine'' is a member of the subfamily Homininae, a ''hominid'' is a member of the family Hominidae, and a ''hominoid'' is a member of the superfamily Hominoidea.</ref> have previously been found.{{contradiction-inline|date=January 2012}}<ref>McBrearty and Jablonski, Nature, 2005</ref> This shows that some chimpanzees lived close to ''Homo'' (''[[H. erectus]]'' or ''[[H. rhodesiensis]]'') at the time; the same is likely true for gorillas.

==Evolution==
{{merge to|Human evolution}}

===Evolution of bipedalism===
{{see also|Human skeletal changes due to bipedalism}}
Recent studies of ''[[Ardipithecus ramidus]]'' (4.4 million years old) and ''[[Orrorin tugenensis]]'' (6 million years old) suggest some degree of bipedalism. ''[[Australopithecus]]'' and early ''[[Paranthropus]]'' may have been [[bipedal]]. Very early hominins such as ''[[Ardipithecus ramidus]]'' may have possessed an arboreal type of bipedalism.<ref>Kivell TL, Schmitt D 2009 Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor. Proc Natl Acad Sci U S A. 2009 Aug 25;106(34):14241-6. {{PMID|19667206}}</ref> and towards efficient walking and running in [[modern humans]].

===Brain size evolution===
There has been a gradual increase in brain volume ([[brain size]]) as the ancestors of modern humans progressed along the [[timeline of human evolution]], starting from about 600&nbsp;cm<sup>3</sup> in ''[[Homo habilis]]'' up to 1500&nbsp;cm<sup>3</sup> in ''[[Homo sapiens neanderthalensis]]''. However, modern ''Homo sapiens'' have a brain volume slightly smaller (1250&nbsp;cm<sup>3</sup>) than Neanderthals, women have a brain slightly smaller than men and the Flores hominids (''[[Homo floresiensis]]''), nicknamed hobbits, had a cranial capacity of about 380&nbsp;cm<sup>3</sup> (considered small for a chimpanzee), about a third of the ''[[Homo erectus]]'' average. It is proposed that they evolved from ''H. erectus'' as a case of insular dwarfism.{{Citation needed|date=March 2012}} In spite of their smaller brain, there is evidence that ''H. floresiensis'' used fire and made stone tools at least as sophisticated as those of their proposed ancestors ''H. erectus''.<ref>{{cite journal |author=Brown P, Sutikna T, Morwood MJ, ''et al.'' |title=A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia |journal=Nature |volume=431 |issue=7012 |pages=1055–61 |year=2004 |pmid=15514638 |doi=10.1038/nature02999}}</ref> In this case, it seems that for intelligence, the structure of the brain is more important than its size.<ref>{{cite web|last=Davidson |first=Iain |url=http://une-au.academia.edu/IainDavidson/Papers/148883/_As_large_as_you_need_and_as_small_as_you_can--implications_of_the_brain_size_of_Homo_floresiensis_ |title=As large as you need and as small as you can'--implications of the brain size of Homo floresiensis, (Iain Davidson) |publisher=Une-au.academia.edu |date= |accessdate=2011-10-30}}</ref>

===Evolution of family structure and sexuality===
{{see also|Human sexuality}}
Sexuality is related to family structure and partly shapes it. The involvement of fathers in education is quite unique to humans, at least when compared to other Homininae. [[Concealed ovulation]] and [[menopause]] in women both also occur in a few other primates however, but are uncommon in other species. [[Testis]] and [[penis size]] seems to be related to family structure: [[monogamy]] or [[promiscuity]], or [[harem]], in humans, chimpanzees or gorillas, respectively.<ref>{{cite book|last=Diamond|first=Jared|title=[[The Third Chimpanzee]]}}</ref><ref name="WiSF">{{cite book|last=Diamond|first=Jared|title=[[Why is Sex Fun?]]}}</ref> The levels of [[sexual dimorphism]] are generally seen as a marker of [[sexual selection]]. Studies have suggested that the earliest hominins were dimorphic and that this lessened over the course of the evolution of the genus ''Homo'', correlating with humans becoming more monogamous, whereas gorillas, who live in harems, show a large degree of sexual dimorphism. Concealed (or "hidden") ovulation means that the phase of fertility is not detectable in women, whereas chimpanzees advertise ovulation via an obvious swelling of the genitals. Women can be partly aware of their ovulation along the menstrual phases, but men are essentially unable to detect ovulation in women. Most primates have semi-concealed ovulation, thus one can think that the common ancestor had semi-concealed ovulation, that was inherited by gorillas, and that later evolved in concealed ovulation in humans and advertised ovulation in chimpanzees. Menopause also occurs in [[rhesus monkeys]], and possibly in chimpanzees, but does not in gorillas and is quite uncommon in other primates (and other mammal groups).<ref name="WiSF"/>

==See also==
*[[Chimpanzee-human last common ancestor]]
*''[[The Third Chimpanzee]]''
{{Wikispecies|Homininae}}
{{Wikibooks|Dichotomous Key|Homininae}}
==References==
{{Reflist|group=Note}}
{{reflist}}
:*<small>"Human Evolutionary Genetics" Jobling M.A., Hurles M., Tyler Smith C. 2004, Garland Science, New York</small>
{{Human Evolution}}
{{Great apes}}