Editing Australopithecus afarensis (section)

==Taxonomy==
===Research history===
Beginning in the 1930s, some of the most ancient [[hominin]] remains of the time dating to 3.8–2.9 million years ago were recovered from East Africa. Because ''[[Australopithecus africanus]]'' fossils were commonly being discovered throughout the 1920s and '40s in South Africa, these remains were often provisionally classified as ''Australopithecus'' [[species affinis|aff.]] ''africanus''.<ref name=Johanson1978/> The first to identify a human fossil was German explorer [[Ludwig Kohl-Larsen]] in 1939 by the headwaters of the Gerusi River (near [[Laetoli]], Tanzania), who encountered a [[maxilla]].<ref>{{cite book|first=V.|last=Morell|year=2011|title=Ancestral Passions: The Leakey Family and the Quest for Humankind's Beginnings|publisher=Simon and Schuster|page=445|isbn=978-1-4391-4387-2}}</ref> In 1948, German palaeontologist [[Edwin Hennig]] proposed classifying it into a new [[genus]], "''Praeanthropus''", but he failed to give a species name. In 1950, German anthropologist [[Hans Weinert]] proposed classifying it as ''Meganthropus africanus'', but this was largely ignored. In 1955, M.S. Şenyürek proposed the combination ''Praeanthropus africanus''.<ref name=Johanson1978/> Major collections were made in [[Laetoli]], Tanzania, on an expedition beginning in 1974 directed by British palaeoanthropologist [[Mary Leakey]], and in [[Hadar, Ethiopia|Hadar]], Ethiopia, from 1972 to 1977 by the International Afar Research Expedition (IARE) formed by French geologist [[Maurice Taieb]], American palaeoanthropologist [[Donald Johanson]] and Breton anthropologist [[Yves Coppens]]. These fossils were remarkably well preserved and many had associated skeletal aspects.<ref name=Kimbel2009>{{cite journal|first1=W. H.|last1=Kimbel|first2=L. K.|last2=Delezene|year=2009|title="Lucy" Redux: A Review of Research on ''Australopithecus afarensis''|journal=American Journal of Physical Anthropology|volume=49|doi=10.1002/ajpa.21183|pmid=19890859|pages=2–48|doi-access=free}}</ref>{{rp|5}} In 1973, the IARE team unearthed the first [[knee joint]], [[AL 129-1]], and showed the earliest example at the time of [[bipedalism]]. On 24 November 1974, Johanson and graduate student Tom Gray discovered the extremely well-preserved skeleton AL 288–1, commonly referred to as "[[Lucy (Australopithecus)|Lucy]]" (named after the 1967 [[The Beatles|Beatles]] song ''[[Lucy in the Sky with Diamonds]]'' which was playing on their [[tape recorder]] that evening).<ref name=Johanson1990>{{cite book|first=D.|last=Johanson|author-link=Donald Johanson|year=1990|chapter=Prologue|title=Lucy: The Beginnings of Humankind|publisher=Simon and Schuster|isbn=978-0-671-72499-3}}</ref> In 1975, the IARE recovered 216 specimens belonging to 13 individuals, [[AL 333]] "the First Family" (though the individuals were not necessarily related).<ref>{{cite journal|first=D. C.|last=Johanson|author-link=Donald Johanson|year=2004|title=Lucy, Thirty Years Later: An Expanded View of ''Australopithecus afarensis''|journal=Journal of Anthropological Research|volume=60|issue=4|doi=10.1086/jar.60.4.3631138|jstor=3631138|pages=465–486|s2cid=159745450}}</ref>{{rp|471–472}} In 1976, Leakey and colleagues discovered [[fossil trackway]]s, and preliminarily classified Laetoli remains into ''[[Homo]]'' spp., attributing ''Australopithecus''-like traits as evidence of them being [[transitional fossil]]s.<ref>{{cite journal|first1=M.|last1=Leakey|author-link=Mary Leakey|first2=R. H.|last2=Ray|first3=G. H.|last3=Curtis|first4=R. E.|last4=Drake|first5=M. K.|last5=Jackes|first6=T. D.|last6=White|author6-link=Tim D. White|year=1976|title=Fossil hominids from the Laetolil Beds|journal=Nature|volume=262|issue=5568|pages=460–466|doi=10.1038/262460a0|pmid=822342|bibcode=1976Natur.262..460L|hdl=2027.42/62755|s2cid=4151505|hdl-access=free}}</ref>

[[File:LH 4 Replica 03.jpg|thumb|left|The [[holotype]] [[LH 4]]]]
In 1978, Johanson, [[Tim D. White]] and Coppens classified the hundreds of specimens collected thus far from both Hadar and Laetoli into a single new species, ''A. afarensis'', and considered the apparently wide range of variation a result of [[sexual dimorphism]]. The [[specific name (zoology)|specific name]] honours the [[Afar Region]] of Ethiopia where the majority of the specimens had been recovered from and replaces Weinert's ''africanus'', which was already [[Homonym (biology)|preoccupied]] by ''Australopithecus africanus''. They later selected the jawbone [[LH 4]] as the [[holotype specimen]] because of its preservation quality and because White had already fully described and illustrated it the year before.<ref name=Johanson1978/>

[[File:Afarensis east Africa.jpg|thumb|left|200px|Locations of ''A. afarensis'' sites]]
''A. afarensis'' is known only from [[East Africa]]. Beyond Laetoli and the Afar Region, the species has been recorded in Kenya at [[Koobi Fora]] and possibly [[Lothagam]]; and elsewhere in Ethiopia at Woranso-Mille, Maka, Belohdelie, [[Ledi-Geraru]] and Fejej.<ref name=Behrensmeyer2013/><ref name=Delson2004/> The [[frontal bone]] fragment BEL-VP-1/1 from the [[Middle Awash]],<ref>{{citation |title=Facts about the Oromo of East Africa |date=May 26, 1995 |url=https://www.africa.upenn.edu/Articles_Gen/Oromo.html |archive-url=https://web.archive.org/web/20210128081800/https://www.africa.upenn.edu/Articles_Gen/Oromo.html |access-date=April 6, 2021 |archive-date=January 28, 2021 |url-status=live}}</ref> Afar Region, Ethiopia, dating to 3.9 million years ago has typically been assigned to ''A. anamensis'' based on age, but may be assignable to ''A. afarensis'' because it exhibits a [[synapomorphy and apomorphy|derived]] form of [[postorbital constriction]]. This would mean ''A. afarensis'' and ''A. anamensis'' coexisted for at least 100,000 years.<ref name=Haile2019/> In 2005, a second adult specimen preserving both skull and body elements, AL 438–1, was discovered in Hadar.<ref>{{cite journal|first1=M. S. M.|last1=Drapeau|first2=C. V.|last2=Ward|first3=W. H.|last3=Kimbel|first4=D. C.|last4=Johanson|author4-link=Donald Johanson|first5=Y.|last5=Rak|year=2005|title=Associated Cranial and Forelimb Remains Attributed to ''Australopithecus afarensis'' From Hadar, Ethiopia|journal=Journal of Human Evolution|volume=48|issue=6|pages=593–642|doi=10.1016/j.jhevol.2005.02.005|pmid=15927662|bibcode=2005JHumE..48..593D }}</ref> In 2006, an infant partial skeleton, [[DIK-1-1]], was unearthed at [[Dikika]], Afar Region.<ref name=Alamseged2006>{{cite journal|first1=Z.|last1=Alamseged|first2=F.|last2=Spoor|first3=W. H.|last3=Kimbel|first4=R.|last4=Bobe|first5=D.|last5=Geraads|first6=D.|last6=Reed|first7=J. G.|last7=Wynn|year=2006|title=A juvenile early hominin skeleton from Dikika, Ethiopia|journal=Nature|volume=443|issue=7109|pages=296–301|doi=10.1038/nature05047|pmid=16988704|bibcode=2006Natur.443..296A|s2cid=4418369}}</ref> In 2015, an adult partial skeleton, [[KSD-VP-1/1]], was recovered from Woranso-Mille.<ref name=Haile2015/>{{rp|1–4}}

For a long time, ''A. afarensis'' was the oldest known African [[great ape]] until the 1994 description of the 4.4-million-year-old ''[[Ardipithecus ramidus]]'',<ref name="Suwa_2009">{{cite journal | title=The ''Ardipithecus ramidus skull'' and its implications for hominid origins | journal=Science | last1=Suwa | first1=G | date=2 October 2009| volume=326 | issue=5949 | pages=68, 68e1–68e7 | doi=10.1126/science.1175825 | last2=Asfaw | first2=B. | last3=Kono | first3=R. T. | last4=Kubo | first4=D. | last5=Lovejoy | first5=C. O. | last6=White | first6=T. D. | pmid=19810194|bibcode = 2009Sci...326...68S | s2cid=19725410 |display-authors=et al.| url=http://doc.rero.ch/record/211453/files/PAL_E4442.pdf }}</ref> and a few earlier or contemporary taxa have been described since, including the 4-million-year-old ''A. anamensis'' in 1995,<ref>{{cite journal |first1=M. G. |last1=Leakey |author-link=Meave G. Leakey |first2=C. S. |last2=Feibel |first3=I. |last3=MacDougall |first4=A. |author3-link=Ian McDougall (geologist) |last4=Walker |author4-link=Alan Walker (anthropologist) |year=1995 |title=New four-million-year-old hominid species from Kanapoi and Allia Bay, Kenya |journal=Nature |pmid=7637803 |volume=376 |issue=6541 |pages=565–571 |doi=10.1038/376565a0 |bibcode=1995Natur.376..565L|s2cid=4340999 }}</ref> the 3.5-million-year-old ''[[Kenyanthropus platyops]]'' in 2001,<ref>{{cite journal|last1=Leakey|first1=M. G.|author-link=Meave Leakey|display-authors=et al.|year=2001|title=New hominin genus from eastern Africa shows diverse middle Pliocene lineages|journal=Nature|volume=410|issue=6827|pages=433–440|bibcode=2001Natur.410..433L|doi=10.1038/35068500|pmid=11260704|s2cid=4409453}}</ref> the 6-million-year-old ''[[Orrorin tugenensis]]'' in 2001,<ref>{{cite journal |last1=Senut |first1=B. |last2=Pickford |first2=M. |last3=Gommery |first3=D.|last4=Mein |first4=P. |last5=Cheboi |first5=K. |last6=Coppens |first6=Y.|author6-link=Yves Coppens |title=First hominid from the Miocene (Lukeino Formation, Kenya) |journal=Comptes Rendus de l'Académie des Sciences, Série IIA |year= 2001 |volume=332 |issue=2 |pages=137–144 |doi=10.1016/S1251-8050(01)01529-4 |bibcode=2001CRASE.332..137S |s2cid=14235881 }}</ref> and the 7- to 6-million-year-old ''Sahelanthropus tchadensis'' in 2002.<ref name=klages>{{cite journal |last1=Brunet |first1=M. |last2=Guy |first2=F. |last3=Pilbeam |first3=D. |author3-link=David Pilbeam|last4=Mackaye |first4=H. T.|display-authors=et al.|year=2002 |title=A new hominid from the Upper Miocene of Chad, Central Africa |journal=[[Nature (journal)|Nature]] |volume=418 |issue=6894| pages=145–151 |doi=10.1038/nature00879 |pmid=12110880|bibcode=2002Natur.418..145B|s2cid=1316969 |url=http://doc.rero.ch/record/13388/files/PAL_E190.pdf }}</ref> Bipedalism was once thought to have evolved in australopithecines, but it is now thought to have begun evolving much earlier in habitually arboreal primates. The earliest claimed date for the beginnings of an upright spine and a primarily vertical body plan is 21.6 million years ago in the [[Early Miocene]] with ''[[Morotopithecus bishopi]]''.<ref>{{cite journal|title=Homeotic Evolution in the Mammalia: Diversification of Therian Axial Seriation and the Morphogenetic Basis of Human Origins |journal = PLOS ONE|volume = 2|issue = 10|pages = e1019|first=Aaron G. |last=Filler |date=October 10, 2007 |doi=10.1371/journal.pone.0001019 |pmid = 17925867|pmc = 2000357 |bibcode = 2007PLoSO...2.1019F|doi-access = free}}</ref>
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===Classification===
''A. afarensis'' is now a widely accepted species, and it is now generally thought that ''Homo'' and ''Paranthropus'' are [[sister taxa]] deriving from ''Australopithecus'', but the classification of ''Australopithecus'' species is in disarray. ''Australopithecus'' is considered a [[evolutionary grade|grade taxon]] whose members are united by their similar physiology rather than close relations with each other over other hominin genera. It is unclear how any ''Australopithecus'' species relate to each other,<ref name="McNulty2016">{{cite journal|first=K. P.|last=McNulty|year=2016|title=Hominin Taxonomy and Phylogeny: What's In A Name?|journal=Nature Education Knowledge|volume=7|issue=1|page=2|url=https://www.nature.com/scitable/knowledge/library/hominin-taxonomy-and-phylogeny-what-s-in-142102877/}}</ref> but it is generally thought that a population of ''[[A. anamensis]]'' evolved into ''A. afarensis''.<ref name="Haile2019">{{cite journal|last1=Haile-Selassie|first1=Y.|author1-link=Yohannes Haile-Selassie|last2=M. Melillo|first2=S.|last3=Vazzana|first3=A.|last4=Benazzi|first4=S.|last5=T.|first5=M. Ryan|year=2019|title=A 3.8-million-year-old hominin cranium from Woranso-Mille, Ethiopia|journal=Nature|volume=573|issue=7773|pages=214–219|doi=10.1038/s41586-019-1513-8|bibcode=2019Natur.573..214H|pmid=31462770|hdl=11585/697577|s2cid=201656331|hdl-access=free}}</ref><ref name="McNulty2016"/><ref name="Kimbel">{{cite journal |last1=Kimbel |first1=W. H. |last2=Lockwood |first2=C. A. |first3=C. V. |last3=Ward |first4=M. G. |last4=Leakey |author4-link=Meave G. Leakey |first5=Y. |last5=Rake |first6=D. C. |last6=Johanson |author6-link=Donald Johanson|title=Was ''Australopithecus anamensis'' ancestral to ''A. afarensis''? A case of anagenesis in the hominin fossil record |journal=Journal of Human Evolution |year=2006 |volume=51 |issue=2 |pages=134–152 |doi=10.1016/j.jhevol.2006.02.003 |pmid=16630646|bibcode=2006JHumE..51..134K }}</ref>

In 1979, Johanson and White proposed that ''A. afarensis'' was the last common ancestor between ''Homo'' and ''[[Paranthropus]]'', supplanting ''A. africanus'' in this role.<ref>{{cite journal|first1=D. C.|last1=Johanson|author-link=Donald Johanson|first2=T. D.|last2=White|author2-link=Tim D. White|year=1979|title=A Systematic Assessment of Early African Hominids|journal=Science|volume=203|issue=4378|pages=321–330|doi=10.1126/science.104384|pmid=104384|bibcode=1979Sci...203..321J}}</ref> Considerable debate of the validity of this species followed, with proposals for [[synonym (taxonomy)|synonymising]] them with ''A. africanus'' or recognising multiple species from the Laetoli and Hadar remains. In 1980, South African palaeoanthropologist [[Phillip V. Tobias]] proposed reclassifying the Laetoli specimens as ''A. africanus afarensis'' and the Hadar specimens as ''A. afr. aethiopicus''.<ref>{{Cite journal|last=Tobias|first=Phillip V.|date=1980|title="Australopithecus afarensis" and A. africanus: Critique and an alternative hypothesis|journal=Palaeontologia Africana|s2cid=81551249}}</ref> The skull KNM-ER 1470 (now ''[[H. rudolfensis]]'') was at first dated to 2.9 million years ago, which cast doubt on the ancestral position of both ''A. afarensis'' or ''A. africanus'', but it has been re-dated to about 2 million years ago.<ref name=Delson2004>{{cite book|first1=E.|last1=Delson|first2=I.|last2=Tattersall|author2-link=Ian Tattersall|first3=J.|last3=Van Couvering|first4=A. S.|last4=Brooks|year=2004|title=Encyclopedia of Human Evolution and Prehistory|edition=2nd|publisher=Routledge|pages=118–120|isbn=978-1-135-58228-9}}</ref> Several ''Australopithecus'' species have since been postulated to represent the ancestor to ''Homo'', but the 2013 discovery of the earliest ''Homo'' specimen, [[LD 350-1]], 2.8 million years old (older than almost all other ''Australopithecus'' species) from the Afar Region could potentially affirm ''A. afarensis''{{'}} ancestral position.<ref name="Villmoare2015">{{cite journal|first1=B.|last1=Villmoare|first2=W. H.|last2=Kimbel|first3=C.|last3=Seyoum|display-authors=et al.|year=2015|title=Early ''Homo'' at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia|journal=Science|volume=347|issue=6228|pages=1352–1355|doi=10.1126/science.aaa1343|doi-access=free|pmid=25739410|bibcode=2015Sci...347.1352V}}</ref> However, ''A. afarensis'' is also argued to have been too derived (too specialised), due to resemblance in jaw anatomy to the robust australopithecines, to have been a human ancestor.<ref name="Rak2007"/>

Palaeoartist [[Walter Ferguson]] has proposed splitting ''A. afarensis'' into "''H. antiquus''", a [[relict population|relict]] [[dryopithecine]] "''Ramapithecus''" (now ''[[Kenyapithecus]]'') and a subspecies of ''A. africanus''. His recommendations have largely been ignored.<ref name=White1994>{{Cite journal|last1=White |first1=T. D.|author-link=Tim D. White|last2=Suwa |first2=G.|author-link2=Gen Suwa|last3=Asfaw |first3=B. |author-link3=Berhane Asfaw|title=''Australopithecus ramidus'', a new species of early hominid from Aramis, Ethiopia |journal=Nature |volume=371 |pages=306–312 |year=1994 |pmid=8090200 |doi=10.1038/371306a0|bibcode=1994Natur.371..306W|issue=6495|s2cid=4347140}}</ref><ref name=Delson2004/> In 2003, Spanish writer [[Camilo José Cela Conde]] and evolutionary biologist [[Francisco J. Ayala]] proposed reinstating "''Praeanthropus''" including ''A. afarensis'' alongside ''[[Sahelanthropus]]'', ''[[A. anamensis]]'', ''[[A. bahrelghazali]]'' and ''[[A. garhi]]''.<ref name="Cela-CondeAyala2003">{{Cite journal | last1 = Cela-Conde | first1 = C. J.|author1-link=Camilo José Cela Conde| last2 = Ayala | first2 = F. J. |author2-link=Francisco J. Ayala| title = Genera of the human lineage | doi = 10.1073/pnas.0832372100 | journal = Proceedings of the National Academy of Sciences | volume = 100 | issue = 13 | pages = 7684–7689 | year = 2003 | pmid = 12794185| pmc = 164648 | bibcode = 2003PNAS..100.7684C| doi-access = free}}</ref> In 2004, Danish biologist Bjarne Westergaard and geologist Niels Bonde proposed splitting off "''Homo hadar''" with the 3.2-million-year-old partial skull AL 333–45 as the holotype, because a foot from the First Family was apparently more humanlike than that of Lucy. In 2011, Bonde agreed with Ferguson that Lucy should be split into a new species, though erected a new genus as "''Afaranthropus antiquus''".<ref>{{cite book|first=N.|last=Bonde|year=2011|title=The Symbolic Species Evolved|chapter=Hominid Diversity and 'Ancestor' Myths|publisher=Springer Nature|isbn=978-94-007-2336-8}}</ref>

In 1996, a 3.6-million-year-old jaw from [[Koro Toro]], Chad, originally classified as ''A. afarensis'' was split off into a new species as ''[[A. bahrelghazali]]''.<ref>{{cite journal|first1=M.|last1=Brunet|author-link=Michel Brunet (paleontologist)|first2=A.|last2=Beauvilain|first3=Y.|last3=Coppens|author3-link=Yves Coppens|last4=Heintz |first4=É. |last5=Moutaye |first5=A. H. E |last6=Pilbeam |first6=D. |author6-link=David Pilbeam|year=1996 |url=https://afanporsaber.com/wp-content/uploads/2017/09/Australopithecus-bahrelghazali-une-nouvelle-esp%C3%A8ce-dHominid%C3%A9-ancien-de-la-r%C3%A9gion-de-Koro-Toro-Tchad.pdf |title=''Australopithecus bahrelghazali'', une nouvelle espèce d'Hominidé ancien de la région de Koro Toro (Tchad) |journal=Comptes Rendus des Séances de l'Académie des Sciences |volume=322 |pages=907–913}}</ref> In 2015, some 3.5- to 3.3-million-year-old jaw specimens from the Afar Region (the same time and place as ''A. afarensis'') were classified as a new species as ''[[A. deyiremeda]]'', and the recognition of this species would call into question the species designation of fossils currently assigned to ''A. afarensis''.<ref>{{Cite journal|doi=10.1038/nature14448|pmid=26017448|title=New species from Ethiopia further expands Middle Pliocene hominin diversity|journal=Nature|volume=521|issue=7553|pages=483–488|year=2015|last1=Haile-Selassie|first1=Y|author1-link=Yohannes Haile-Selassie|last2=Gibert|first2=L.|last3=Melillo|first3=S. M.|last4=Ryan|first4=T. M.|last5=Alene|first5=M.|last6=Deino|first6=A.|last7=Levin|first7=N. E.|last8=Scott|first8=G.|last9=Saylor|first9=B. Z.|bibcode=2015Natur.521..483H|s2cid=4455029}}</ref> However, the validity of ''A. bahrelghazali'' and ''A. deyiremeda'' is debated.<ref>{{cite journal|first1=F.|last1=Spoor|first2=M. G.|last2=Leakey|author2-link=Meave Leakey|first3=P.|last3=O'Higgins|year=2016|title=Middle Pliocene hominin diversity: ''Australopithecus deyiremeda'' and ''Kenyanthropus platyops''|journal=Philosophical Transactions of the Royal Society B|volume=371|issue=1698|page=20150231|doi=10.1098/rstb.2015.0231|pmc=4920288|pmid=27298462}}</ref> Wood and Boyle (2016) stated there was "low confidence" that ''A. afarensis'', ''A. bahrelghazali'' and ''A. deyiremeda'' are distinct species, with ''[[Kenyanthropus|Kenyanthropus platyops]]'' perhaps being indistinct from the latter two.<ref name=":0">{{Cite journal|last1=Wood|first1=Bernard|last2=K. Boyle|first2=Eve|date=January 2016|title=Hominin taxic diversity: Fact or fantasy?: HOMININ TAXIC DIVERSITY|journal=American Journal of Physical Anthropology|language=en|volume=159|issue=Suppl 61|pages=37–78|doi=10.1002/ajpa.22902|pmid=26808110|doi-access=free}}</ref>
{{African hominin timeline}}