Ardi: Difference between revisions

[[{{Infobox fossil|image=File:Ardipithecis Ramidus skeleton 1994-1996.jpeg|thumbspecies=''[[Ardipithecus ramidus]]''|uprightage=4.4 million years|place discovered=[[Aramis, Ethiopia|Aramis]], [[Afar Region|Afar]], [[Ethiopia]]|date discovered=1994|discovered by=[[Yohannes Haile-Selassie]]|catalog number=|common name=Ardi|caption=The recovered fragments of Ardi's skeleton]]}}

'''Ardi''' (ARA-VP-6/500) is the designation of the fossilized skeletal remains of an ''[[Ardipithecus ramidus]]'', thought to be an early human-like female anthropoid 4.4 million years old. It is the most complete early [[hominid]] specimen, with most of the skull, teeth, pelvis, hands and feet,<ref name="ScienceMag 10-2009">{{cite journal |title=A new kind of ancestor: ''Ardipithecus'' unveiled |author=Ann Gibbons |url=https://www.science.org/doi/abs/10.1126/science.326.5949.36?sid=00efc161-9322-4705-9b91-273ee6659876 |journal=[[Science (journal)|Science]] |date=2 October 2009 |volume=326 |issue=5949 |pages=36–40 |doi=10.1126/science.326.5949.36 |pmid=19797636 |accessdate=June 23, 2013}}</ref> more complete than the previously known ''[[Australopithecus afarensis]]'' specimen called "[[Lucy (Australopithecus)|Lucy]].". In all, 125 different pieces of fossilized bone were found.<ref>{{Cite magazine|url=http://content.time.com/time/magazine/article/0,9171,1927289,00.html|title=Ardi Is a New Piece for the Evolution Puzzle|last1=Lemonick|first1=Michael D.|date=2009-10-01|magazine=Time|access-date=2017-10-01|last2=Dorfman|first2=Andrea|language=en-US|issn=0040-781X}}</ref>

The ''Ardi'' skeleton was discovered at [[Aramis, Ethiopia|Aramis]] in the arid badlands near the [[Awash River]] in Ethiopia in 1994 by a college student, [[Yohannes Haile-Selassie]], when he uncovered a partial piece of a hand bone. The discovery was made by a team of scientists led by UC Berkeley anthropologist, [[Tim D. White]],<ref name="Lemonick_2009">{{cite magazine |title=Ardi is a new piece for the evolution puzzle |magazine=[[Time (magazine)|Time]] |last1=Lemonick |first1=M. D. |last2=Dorfman |first2=D. |date=1 October 2009 |accessdate=October 6, 2009 |url=http://www.time.com/time/health/article/0,8599,1927200,00.html?xid=rss-health|archive-url=https://web.archive.org/web/20100601042849/http://www.time.com/time/health/article/0,8599,1927200,00.html?xid=rss-health|url-status=dead|archive-date=June 1, 2010}}</ref><ref>{{cite news |title='Ardi' may rewrite the story of humans: 1.4 million-year-old primate helps bridge evolutionary gap |newspaper=[[The Washington Post]] |last=Achenbach |first=J. | date=2 October 2009 |accessdate=October 3, 2009 |url=https://www.washingtonpost.com/wp-dyn/content/article/2009/10/01/AR2009100103432.html?wprss=rss_technology}}</ref><ref name="Amos_2009">{{cite news |title=Fossil finds extend human story |newspaper=The [[BBC]] |last=Amos |first=J. |date=1 October 2009 |accessdate=October 6, 2009 |url=http://news.bbc.co.uk/2/hi/science/nature/8285180.stm |archiveurl=https://web.archive.org/web/20091006082216/http://news.bbc.co.uk/2/hi/science/nature/8285180.stm |archivedate=6 October 2009 |url-status=live}}</ref> and was analyzed by an international group of scientists that included [[Owen Lovejoy (anthropologist)|Owen Lovejoy]] heading the biology team. On 1 October 2009, the journal ''[[Science (journal)|Science]]'' published an [[Open access (publishing)|open-access]] collection of eleven articles, detailing many aspects of ''A. ramidus'' and its environment.<ref>{{cite web |title=Online extras: Ardipithecus ramidus |publisher=Science |accessdate=October 6, 2009 |url=http://www.sciencemag.org/ardipithecus/ |archiveurl=https://web.archive.org/web/20091005000048/http://www.sciencemag.org/ardipithecus/ |archivedate=5 October 2009 |url-status=live }}</ref> Her fossils were also found near animal remains which indicated that she inhabited a forest type of environment, contrary to the theory that bipedalism originated in savannahs[[savannah]]s.<ref>{{citation |publisher=[[Smithsonian's National Museum of Natural History]], The Smithsonian Institution's Human Origins Program |title=Ardipithecus Ramidus |year=2010 |access-date=November 17, 2016 |url=http://humanorigins.si.edu/evidence/human-fossils/species/ardipithecus-ramidus}}</ref>

[[File:Ardipithecus ramidus, artistic reconstruction.jpg|thumb|left|250px|Scientific [[paleoart]]ist [[Jay Matternes]]' rendition of Ardi]]

Ardi weighed about {{convert|50|kg|lb|abbr=on}}, and could be up to {{convert|120|cm|ft|abbr=on}} tall. Although she is a biped, Ardi had both opposable big toes and thumbs in order to climb trees. It is speculated that her bipedality impeded movement, but enabled her to bear more offspring.<ref name="Shreeve 07-2010">{{cite magazine |last=Shreeve |first=Jamie |title=The Evolutionary Road |magazine=The [[National Geographic]], [[Print (magazine)|Print]] |volume=218 |issue=1 |url=https://www.nationalgeographic.com/magazine/2010/07article/middle-awash/ |date=July 2010 |pages=38–67}}</ref>{{rp|67}}{{unclear inline|date=June 2022}}

Although it is not yet clear how Ardi's species is related to ''[[Homo sapiens]]'', the discovery is of great significance and added much to the debate on ''[[Ardipithecus]]'' and its place in [[human evolution]]. With regards to Ardi's body composition, archaeologists note that she is unique in that she possesses traits that are characteristic of both extinct primates and early hominids.<ref name="Shreeve 07-2010" />{{rp|63}} It is still a point of debate whether Ardi was capable of bipedal movement. Ardi's divergent big toes are not characteristic of a biped.<ref name="Shreeve 07-2010" />{{rp|66}} However, the found remains of her legs, feet, pelvis, and hands suggested that she walked upright when on the ground but was a quadruped when moving around trees. Her big toe, for example, spreads out quite a bit from her foot to better grasp tree limbs. Unlike chimpanzees, however, her foot contains a unique small bone inside a tendon which kept the big toe stronger. When seen along with Ardi's other bone structures, this unique bone would have helped her [[Walking|walk]] bipedally, though less efficiently than Lucy.<ref name="Shreeve 10-2009">{{cite news |last=Shreeve |first=Jamie |url=https://news.nationalgeographic.com/news/2010/10/101025-oldest-human-fossil-china-out-of-africa-science/ |archive-url=https://web.archive.org/web/20101027083341/http://news.nationalgeographic.com/news/2010/10/101025-oldest-human-fossil-china-out-of-africa-science/ |url-status=dead |archive-date=October 27, 2010 |title=Oldest Modern Human Outside of Africa Found |newspaper=[[National Geographic News|National Geographic]] |date=2009-10-01 |access-date=2016-12-01}}</ref> Her wrist bones also provided her with flexibility but the palm bones were short. This suggests that Ardi did not walk on her knuckles and only used her palms to move along tree branches.<ref>{{citation |last=Dorey |first=Fran |title=Ardipithecus Ramidus |publisher=[[The Australian Museum]] |access-date=2016-12-01 |url=http://australianmuseum.net.au/ardipithecus-ramidus}}</ref>

Some of Ardi's teeth are still connected to her jawbone and show enamel wear suggesting a diet consisting of fruit and nuts.<ref name="Shreeve 07-2010" />{{rp|38}} The canine teeth of ''A. ramidus'' are smaller, and equal in size between males and females. This suggests reduced male-to-male conflict, [[pair-bonding]], and increased parental investment.<ref name="Reexamininghuman">{{citation |title=Reexamining human origins in light of Ardipithecus ramidus |first=C. Owen |last=Lovejoy |journal=Science |date=2009-10-02 |volume=326 |issue=74|pages=74e1–8 |doi=10.1126/science.1175834 |pmid=19810200 |bibcode=2009Sci...326...74L |s2cid=42790876 |url=http://doc.rero.ch/record/211449/files/PAL_E4439.pdf }}</ref> "Thus fundamental reproductive and social behavioral changes probably occurred in hominids long before they had enlarged brains and began to use stone tools."<ref name="Oldest Skeleton of Human Ancestor Found">{{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|publisher = National Geographic|title = Oldest Skeleton of Human Ancestor Found|date = October 2009|accessdate = 2009-10-01}}</ref>

Although ''Ardipithecus'' had more ancestral hands, feet, and limbs,<ref name=":0">{{Cite journalweb |last1=Shook |first1=Beth |last2=Nelson |first2=Katie |last3=Aguilera |first3=Kelsie |last4=Braff |first4=Lara |last5=Eds |date=9 December 2019-12-09 |title=Early Hominins |url=https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/chapter/chapter-9-early-hominins-2/ |language=en |work=[[University of Hawaii]] |accessdate=13 December 2023}}</ref> Ardi’sArdi's pelvis gives a different perspective. The parts of Ardi’sArdi's pelvis that were recovered include her left hip, her right ilium, and a fragment of her distal sacrum.<ref name=":1">{{Cite journal |last1=Lovejoy |first1=C. Owen |last2=Suwa |first2=Gen |last3=Spurlock |first3=Linda |last4=Asfaw |first4=Berhane |last5=White |first5=Tim D. |date=2009-10-02 |title=The Pelvis and Femur of Ardipithecus ramidus: The Emergence of Upright Walking |url=https://www.science.org/doi/abs/10.1126/science.1175831 |journal=Science |volume=326 |issue=5949 |pages=71e1–6 |language=EN |doi=10.1126/science.1175831|pmid=19810197 |bibcode=2009Sci...326...71L |s2cid=19505251 }}</ref> A shorter ilium and a curve in the lower spine<ref name=":1" /> were the characteristics gathered from these partial remains that indicate Ardi, and the ''Ardipithecus ramidus'' species, had the ability to walk upright.<ref name=":0" /> The shift to bipedality is only beginning to emerge in Ardi because there are characteristics in Ardi’sArdi's pelvis that are both found in all later hominids and characteristics that are found in extant African apes.<ref name=":2">{{Cite journal |last1=White |first1=Tim D. |last2=Asfaw |first2=Berhane |last3=Beyene |first3=Yonas |last4=Haile-Selassie |first4=Yohannes |last5=Lovejoy |first5=C. Owen |last6=Suwa |first6=Gen |last7=WoldeGabriel |first7=Giday |date=2009-10-02 |title=Ardipithecus ramidus and the Paleobiology of Early Hominids |url=https://www.science.org/doi/abs/10.1126/science.1175802 |journal=Science |volume=326 |issue=5949 |pages=64–86 |language=EN |doi=10.1126/science.1175802|bibcode=2009Sci...326...75W |s2cid=20189444 }}</ref> A characteristic that is found in Ardi and in all later hominids is a separate growth site for the anterior inferior iliac spine.<ref name=":2" /> A similar ischial structure is a characteristic found in Ardi and in extant African apes.<ref name=":2" /> This mixture of characteristics indicates Ardi’sArdi's bipedality was an earlier version of bipedalism compared to later hominids like [[Lucy (Australopithecus)|Lucy]].<ref name=":1" /> Regardless of how ancestral Ardi’sArdi's bipedality was, these characteristics found in Ardi’sArdi's pelvis show [[bipedalism]] was well underway by 4.4 million years ago, even with the ability for arboreal locomotion still present in the hands and limbs.<ref name=":1" />

Ardi’sArdi's foot is a special area of interest when examining the evolution of bipedalism in early Hominids, and the bipedality of ''Ardipithecus ramidus,'' because all five toes do not line up.<ref name=":3">{{Cite journal |last=Shreeve |first=Jamie |date=2010-07-01 |title=The Birth of Bipedalism |url= |journal=National Geographic |volume=218 |issue=1 |pages=61–67 |via=Ebsco Host}}</ref> The remains of the foot from Ardi and other ''Ardipithecus ramidus'' specimens that can be studied includes “a"a talus, medial and intermediate cuneiforms, cuboid, first, second, third, and fifth metatarsals, and several phalanges.<ref>{{Cite journal |last1=Lovejoy |first1=C. Owen |last2=Latimer |first2=Bruce |last3=Suwa |first3=Gen |last4=Asfaw |first4=Berhane |last5=White |first5=Tim D. |date=2009-10-02 |title=Combining Prehension and Propulsion: The Foot of Ardipithecus ramidus |url=https://www.science.org/doi/abs/10.1126/science.1175832 |journal=Science |volume=326 |issue=5949 |pages=72e1–8 |language=EN |doi=10.1126/science.1175832|pmid=19810198 |bibcode=2009Sci...326...72L |s2cid=26778544 }}</ref>”" The foot of Ardi contains an opposable hallux (big toe) that is similar to [[Chimpanzee|chimpanzees]].<ref name=":0" /> This opposable hallux is believed to have been used to aid in tree climbing.<ref name=":0" /> On the outside, Ardi’sArdi's foot may look like it belongs with other Apes, but on the inside, Ardi’sArdi's foot contains a bone called the os peroneum, which allows the bottom of the foot to be more rigid.<ref name=":3" /> The rigidity of the bottom of the foot was believed to allow Ardi to walk upright, and the other four toes that were aligned performed the “toe"toe off”off" action during a bipedal motion.<ref name=":3" /> The combination of features found in Ardi’sArdi's and other ''Ardipithecus ramidus'' foot bones captures a moment in time where these primitive primates were beginning to leave the trees and spending longer periods of time on the ground.<ref name=":3" />