Editing Ardipithecus (section)

=== Ardi ===
{{Main|Ardi}}
On October 1, [[2009 in science|2009]], paleontologists formally announced the discovery of the relatively complete ''A. ramidus'' fossil skeleton first unearthed in 1994. The fossil is the remains of a small-brained {{Convert|50|kg|adj=on}} female, nicknamed "Ardi", and includes most of the skull and teeth, as well as the pelvis, hands, and feet.<ref name="NewKind"/> It was discovered in Ethiopia's harsh [[Afar Region|Afar desert]] at a site called [[Aramis, Ethiopia|Aramis]] in the Middle Awash region. Radiometric dating of the layers of volcanic ash encasing the deposits suggest that Ardi lived about 4.3 to 4.5 million years ago. This date, however, has been questioned by others. Fleagle and Kappelman suggest that the region in which Ardi was found is difficult to date radiometrically, and they argue that Ardi should be dated at 3.9 million years.<ref name="10.1038/nature09709">{{cite journal |doi=10.1038/376558b0 |pmid=7503900 |last1=Kappelman |first1= John| last2=Fleagle |first2= John G.| date=1995 |title=Age of early hominids |journal=[[Nature (journal)|Nature]] |volume=376 |issue=6541| pages=558–559 |bibcode=1995Natur.376..558K |s2cid=5527405 }}</ref>

The fossil is regarded by its describers as shedding light on a stage of human evolution about which little was known, more than a million years before [[Lucy (Australopithecus)|Lucy]] (''Australopithecus afarensis''), the iconic early human ancestor candidate who lived 3.2 million years ago, and was discovered in 1974 just {{cvt|74|km}} away from Ardi's discovery site. However, because the "Ardi" skeleton is no more than 200,000 years older than the earliest fossils of ''Australopithecus'', and may in fact be younger than they are,<ref name="10.1038/nature09709"/> some researchers doubt that it can represent a direct ancestor of ''Australopithecus''.

Some researchers infer from the form of her pelvis and limbs and the presence of her [[Abduction (kinesiology)|abductable]] [[hallux]], that "Ardi" was a [[facultative biped]]: [[biped]]al when moving on the ground, but [[quadruped]]al when moving about in tree branches.<ref name="AndThePaleobiology">{{cite journal |doi=10.1126/science.1175802 |pmid=19810190 |title=Ardipithecus ramidus and the Paleobiology of Early Hominids |journal=Science |volume=326 |issue=5949 |pages=75–86 |year=2009 |last1=White |first1=T. D. |last2=Asfaw |first2=B. |last3=Beyene |first3=Y. |last4=Haile-Selassie |first4=Y. |last5=Lovejoy |first5=C. O. |last6=Suwa |first6=G. |last7=Woldegabriel |first7=G. |bibcode=2009Sci...326...75W |s2cid=20189444 }}</ref><ref>{{cite web|url= http://news.nationalgeographic.com/news/2009/10/091001-oldest-human-skeleton-ardi-missing-link-chimps-ardipithecus-ramidus.html |archive-url= https://web.archive.org/web/20091004002647/http://news.nationalgeographic.com/news/2009/10/091001-oldest-human-skeleton-ardi-missing-link-chimps-ardipithecus-ramidus.html |url-status= dead |archive-date= October 4, 2009 |title=Oldest Skeleton of Human Ancestor Found |first=Jamie |last=Shreeve |publisher=[[National Geographic magazine]] |date=2009-10-01 |access-date=March 18, 2017 }}</ref><ref>{{cite journal|url= https://www.science.org/content/article/ancient-skeleton-may-rewrite-earliest-chapter-human-evolution |title=Ancient Skeleton May Rewrite Earliest Chapter of Human Evolution |first=Ann |last=Gibbons |journal=[[Science (journal)|Science]] |date=October 2009 |access-date=March 18, 2017 }}</ref> ''A. ramidus'' had a more primitive walking ability than later hominids, and could not walk or run for long distances.<ref>{{cite news|url= http://news.bbc.co.uk/1/hi/sci/tech/8285180.stm |work=BBC News |title=Fossil finds extend human story |date=October 1, 2009 |first=Jonathan |last=Amos}}</ref> The teeth suggest [[omnivory]], and are more generalised than those of modern apes.<ref name="AndThePaleobiology"/>

<gallery>
File:Ardipithecus (finger bones).jpg|Casts of Ardi's finger bones.
</gallery>