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{{short description|Extinct hominine genus from the Miocene}}
{{short description|Extinct hominine genus from the Miocene}}
{{Speciesbox
{{Speciesbox
| fossil_range = {{fossil range|Tortonian|Messinian}}
| fossil_range = [[Tortonian]], {{fossil range|8}}
| image =
| display_parents = 3
| display_parents = 3
| genus = Chororapithecus
| genus = Chororapithecus
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'''''Chororapithecus''''' is an extinct [[great ape]] from the [[Afar region]] of Ethiopia roughly 8 million years ago during the [[Late Miocene]], comprising one species, '''''C. abyssinicus'''''. It is known from 9 isolated teeth discovered in a 2005–2007 survey of the [[Chorora Formation]]. The teeth are indistinguishable from those of [[gorilla]]s in terms of absolute size and relative proportions, and it has been proposed to be an early member of [[Gorillini]]. However, this is controversial given the paucity of remains, and notable anatomical differences between ''Chororapithecus'' and gorilla teeth. The Kenyan [[ape]] ''[[Nakalipithecus]]'' has been proposed to be an ancestor of ''Chororapithecus'' or at least closely related. If correct, they would be the only identified fossil members of any modern non-[[human]] great ape lineage,{{dubious|date=January 2022}} and would push the gorilla–human [[last common ancestor]] from 8 million years ago (identified by molecular analysis) to 10 million years ago. The teeth are adapted for processing tough plant fibres as well as hard, brittle food, and the formation is thought to represent a forested lakeside habitat.
'''''Chororapithecus''''' is an extinct [[homininae|hominine]] genus that lived during the [[Miocene]] and is represented by one species, '''''Chororapithecus abyssinicus'''''. It is believed to be the earliest known [[species]] of the tribe [[Gorillini]].<ref name="suwa">{{cite journal |title=A new species of great ape from the late Miocene epoch in Ethiopia |last=Suwa |first=Gen |author2=Reiko T. Kono |author3=Shigehiro Katoh |author4-link=Berhane Asfaw |author4=Berhane Asfaw |author5-link=Yonas Beyene |author5=Yonas Beyene |journal=[[Nature (journal)|Nature]] |volume=448 |issue=7156 |pages=921–924 |date=2007-08-23 |doi=10.1038/nature06113 |pmid=17713533}}</ref> It was originally interpreted as living about {{mya|10|10.5|million years ago}}, and its existence was thought to indicate that the last [[Common descent|common ancestor]] between the [[Hominini|human/chimpanzee lineage]] and gorillas may have lived greater than {{mya|10|11|million years ago}}, which is at least 2 million years earlier than the previously thought date of divergence of about 8 million years ago.<ref name="dalton">{{cite journal|last=Dalton |first=Rex |date=2007-08-23 |title=Oldest gorilla ages our joint ancestor |journal=[[Nature (journal)|Nature]] |volume=448 |issue=7156 |pages=844–5 |doi=10.1038/448844a |pmid=17713490|doi-access=free }}</ref> However, a subsequent study by Katoh ''et al.'' (2016) dated its fossils to ~8 million years ago.<ref>{{Cite journal|author1=Shigehiro Katoh |author2=Yonas Beyene |author3=Tetsumaru Itaya |author4=Hironobu Hyodo |author5=Masayuki Hyodo |author6=Koshi Yagi |author7=Chitaro Gouzu |author8=Giday WoldeGabriel |author9=William K. Hart |author10=Stanley H. Ambrose |author11=Hideo Nakaya |author12=Raymond L. Bernor |author13=Jean-Renaud Boisserie |author14=Faysal Bibi |author15=Haruo Saegusa |author16=Tomohiko Sasaki |author17=Katsuhiro Sano |author18=Berhane Asfaw |author19=Gen Suwa |year=2016 |title=New geological and palaeontological age constraint for the gorilla–human lineage split |journal=Nature |volume=530 |issue=7589 |pages=215–218 |doi=10.1038/nature16510 |pmid=26863981}}</ref>
{{Human timeline}}
==Taxonomy==
''Chororapithecus'' teeth were discovered in the [[Afar region]], Ethiopia, in a 2005–2007 survey in the Beticha [[locality (geology)|locality]] of the [[Chorora Formation]], hence the name, and the formation itself is named after the Chorora village about {{cvt|8|km}} south of the locality. The specific name, ''abyssinicus'', is in reference to [[Abyssinia]], the former name of Ethiopia. The ape was described in 2007 by anthropologists [[Gen Suwa]], Reiko Kono, Shigehiro Katoh, [[Berhane Asfaw]], and [[Yonas Beyene]].<ref name="suwa">{{cite journal |title=A new species of great ape from the late Miocene epoch in Ethiopia |last1=Suwa |first1=G.|author1-link=Gen Suwa|first2=R. T.|last2=Kono |first3=S.|last3=Katoh |author4-link=Berhane Asfaw |first4=B.|last4=Asfaw |author5-link=Yonas Beyene |first5=Y.|last5=Beyene |journal=Nature |volume=448 |issue=7156 |pages=921–924 |year=2007|doi=10.1038/nature06113 |pmid=17713533|bibcode=2007Natur.448..921S |s2cid=4312331 |url=http://doc.rero.ch/record/15562/files/PAL_E2980.pdf }}</ref>


{{cladogram|title=[[Hominidae]]|align=left|caption=Family tree showing ''Chororapithecus'' as a [[stem group|stem]] gorilla<ref name=Katoh2016/>
The only evidence found of this [[extinction|extinct]] ape is currently nine fossilized teeth of at least three individuals, recovered from the [[Chorora Formation]] which runs along the southern [[Afar Depression]] of [[Ethiopia]] (the same place where the remains of [[Lucy (Australopithecus)|Lucy]] were discovered in 1974). Analysis of eight [[Molar (tooth)|molars]] (two of them fragmented) and a [[canine tooth]] show that their structure is partly similar to modern gorillas.<ref name="suwa" />
|cladogram=
{{clade
|1={{clade
|1=''[[Kenyapithecus]]''
|2={{clade
|1=''[[Nakalipithecus]]'' (as a stem [[hominid]])
|label2=[[Homininae]]
|2={{clade
|label1=[[Gorillini]]
|1={{clade
|1=''Nakalipithecus'' (as a stem gorilla)
|2={{clade
|1='''''Chororapithecus'''''
|2=[[Gorilla]]s
}}
}}
|label2=[[Hominini]]
|2={{clade
|1={{clade
|1=[[Chimpanzee]]
|2=[[Bonobo]]
}}
|2={{clade
|1=''[[Ardipithecus]]''
|2={{clade
|1=''[[Australopithecus]]''
|2=''[[Homo]]'' (humans)
}}
}}
}}
}}
}}}}}}}}
The remains represent at least 3, perhaps over 6, different individuals. The [[holotype specimen]], CHO-BT 4, is a right upper second [[molar (tooth)|molar]], and the [[paratype]]s are a left lower [[canine tooth|canine]], 3 right upper third molars, a left lower third molar, a left lower first molar, and a left and a right lower molar fragment, making for a total of 9 isolated teeth. The discoverers noted the teeth have some of the same adaptations for shearing food as those of [[gorilla]]s, and classified it as the first fossil member and the only other [[genus]] of the [[tribe (taxonomy)|tribe]] [[Gorillini]]. Because the ''Chororapithecus'' teeth have several specializations not shared with those of gorillas (they exhibit a [[synapomorphy and apomorphy|derived]] condition compared to the presumed last common ancestor, LCA), they did not consider it as ancestral to the gorilla.<ref name=suwa/> However, the discovers also conceded it is possible that ''Chororapithecus'' and gorillas instead [[convergent evolution|convergently evolved]] the same teeth due to a similar diet.<ref name="suwa"/> If ''Chororapithecus'' is not a gorillin, it may be a [[stem group|stem]] [[Homininae|hominine]]<ref name=Schroer2013>{{cite book|first1=K.|last1=Schroer|first2=B.|last2=Wood|author2-link=Bernard Wood (geologist)|year=2013|title=Anthropological Perspectives on Tooth Morphology: Genetics, Evolution, Variation|publisher=Cambridge University Press|pages=183–184|isbn=978-1-139-61950-9}}</ref> or not a hominine at all.<ref name=Begun2010>{{cite journal|first=D. R.|last=Begun|year=2010|title=Miocene Hominids and the Origins of the African Apes and Humans|journal=Annual Review of Anthropology|volume=39|page=77<!--only citing this page-->|doi=10.1146/annurev.anthro.012809.105047}}</ref>


The teeth were originally dated to 10.5–10 million years ago (mya), and the discoverers then concluded that the gorilla–human LCA existed about 12 mya, but they were re-dated to about 8 mya. If ''Chororapithecus'' was indeed a [[stem group|stem]] gorilla, the latter date is more consistent with the timing of 8 mya for the LCA according to molecular data. Based on the revised date and similarly large premolar size, the 10 million year old Kenyan ''Nakalipithecus'' has been proposed to have been the ancestor to ''Chororapithecus'', which would move the LCA to 10 mya if correct.<ref name=Katoh2016>{{cite journal|first1=S.|last1=Katoh|first2=Y.|last2=Beyene|first3=T.|last3=Itaya|display-authors=et al.|year=2016|title=New geological and palaeontological age constraint for the gorilla–human lineage split|journal=Nature|volume=530|issue=7589|pages=215–218|doi=10.1038/nature16510|pmid=26863981|bibcode=2016Natur.530..215K|s2cid=205247254}}</ref> Nonetheless, because there are so few remains known, its relations to modern [[great ape]]s is unclear. It was the first extinct ape to have been proposed to be a member of the gorilla lineage.<ref name="dalton">{{cite journal|last=Dalton |first=Rex |year=2007 |title=Oldest gorilla ages our joint ancestor |journal=Nature News |volume=448 |issue=7156 |pages=844–845 |doi=10.1038/448844a |pmid=17713490|bibcode=2007Natur.448..844D |doi-access=free }}</ref>
The researchers compared the make-up of the teeth to those of other current and fossil apes, and concluded that the new ape fossils were possibly those of a species of gorilla which ate mostly high-fiber plants, and that the fossil species is likely a 'direct ancestor' of the gorillas currently living in Africa. Alternatively, the idea that the finds are the remains of early [[hominin]]s has not been ruled out entirely.<ref name="dalton" />


It is debated if great apes evolved in Africa or Eurasia given the abundance of early fossil apes species in the latter and the paucity in the former, despite all modern great apes except the [[orangutan]] being known from Africa. The first Miocene African great ape was discovered in 1997, ''[[Samburupithecus]]'', and the only others known are ''[[Nakalipithecus]]'' and ''Chororapithecus''. If ''Chororapithecus'' is indeed an early gorilla, then it would point to an African origin for great apes.<ref name=Katoh2016/><ref name="dalton" /> However, earlier Eurasian [[dryopithecine]]s may be early hominines.<ref name=Begun2010/>
==Previous research==
Previous efforts to find fossils of great ape ancestors in Africa from between 12 and 8 million years ago had been largely unsuccessful. This absence led some to hypothesize that apes were absent from Africa during this time, and had recolonized Africa from areas in Asia where fossils from this time period are more plentiful. Molecular estimates that humans and gorillas diverged after 8 million years ago were consistent with this idea, in which an [[adaptive radiation]] might have occurred after a single species entered Africa and began to adapt to different environments.


==Anatomy==
Current fossils and research prior to this finding indicate that the evolutionary split between gorillas and humans occurred around 8 million years ago. The new fossils indicate that the split may have happened as long as 10.5 million years ago. It is thought that humans shared a common ancestor with [[Pan (genus)|chimpanzees]] as recently as {{mya|4|7|million years ago}}. <!-- Per [[Chimpanzee]] but needs a cite. Note: 5-6 Myr date is given in abstract of current Nature article -->
The teeth, both in absolute size and relative proportions, are the same as in gorillas, and the molars range in size between the largest and smallest of what is normally seen in adult gorillas. Like in gorillas, the upper molars have a long [[protocone]] crest, and the lower molars have a correspondingly long [[trigonid]] crest, which increase shearing efficacy. Compared to gorillas, the cusp tips are relatively peripheral, are not well pronounced, and the [[tooth enamel|enamel]] is thicker especially at the side cusps where the tooth borders other teeth. This causes a wide basin on the middle of the molar.<ref name="suwa"/> This is reminiscent of the condition seen in [[Hominini]] (humans and [[chimpanzee]]s).<ref name=Schroer2013/> The upper molars are elongated and narrow, and also have a gorilla-like enamel-[[dentine]] juncture.<ref name="suwa"/>


==Palaeobiology==
==Possible implications==
[[File:Gorilla Male skull base.png|thumb|The molars of ''Chororapithecus'' have similarities to those of a gorilla (visible above)]]
"Based on this fossil, that means the split is much earlier than has been anticipated by the molecular evidence. That means everything has to be put back," said researcher at the Rift Valley Research Service in Ethiopia and a co-author of the study, [[Berhane Asfaw]]. This refers to the [[Molecular clock#Calibration|calibration of the molecular clock]], the average rate of fixation of [[neutral mutation]]s in the human and ape ancestors living in this environment over the past 10 million years. The human-gorilla split could have occurred 10 million years ago only if the mutations arose five times more slowly than previously thought, suggesting that other common ancestors of [[great apes]] likewise arose longer ago than believed.{{citation needed|date=August 2012}}
The teeth exhibit adaptations for shearing, but the low cusp height indicates the teeth likely folded and pulverised tough plant fibres rather than cut through them as gorillas and other [[folivore]]s with higher cusps do. The thick enamel is more similar to that of [[orangutan]]s, and may indicate the consumption of hard, brittle foods.<ref name="suwa"/> Orangutan molars are probably adapted for eating hard fruits and nuts.<ref>{{cite journal|first=R. T.|last=Kono|year=2004|title=Molar enamel thickness and distribution patterns in extant great apes and humans: new insights based on a 3-dimensional whole crown perspective|journal=Anthropological Science|volume=112|issue=2|page=121|doi=10.1537/ase.03106|doi-access=free}}</ref> ''Chororapithecus'' and ''[[Oreopithecus]]'' are the only known folivorous Miocene apes.<ref name="suwa"/>


The Chorora Formation represents a braided river system, possibly a forested area alongside a lake in a [[forest-savanna mosaic]] environment.<ref name="suwa"/> It is the only [[sub-Saharan Africa|sub-Saharan]] vertebrate-bearing formation spanning from 9–7.4 mya, and records the earliest known occurrences of [[cercopithecine]] monkeys, [[hippo]]s, and [[rabbit]]s in Africa. At the Beticha locality, the large vertebrate assemblage is: colobine and cercopithecine monkeys, a hippo, the pig ''[[Nyanzachoerus]]'', the antelope-like [[Sivatherium|siveratheriine]] and ''[[Palaeotragus]]'', a [[Boselaphini|bosalephine]] antelope, [[Bovini|wild cattle]], the horse ''[[Cormohipparion]]'' and an unidentified [[equine]], a rhino, what may be the elephant ''[[Stegotetrabelodon]]'', a [[Percrocutidae|percrocutid]] [[hyena]], and a large cat. Because horses and [[rodent]]s are much less common in the Beticha locality than the [[type locality (geology)|type locality]] of the formation, Beticha may have been a comparatively more forested and closed environment.<ref name=suwa2015>{{cite journal|first1=G.|last1=Suwa|author1-link=Gen Suwa|first2=Y.|last2=Beyene|first3=H.|last3=Nakaya|display-authors=et al.|year=2015|title=Newly discovered cercopithecid, equid and other mammalian fossils from the Chorora Formation, Ethiopia|journal=Anthropological Science|volume=123|issue=1|pages=19–39|doi=10.1537/ase.150206|doi-access=free}}</ref>
==Other expert opinions==
Despite the finds, other researchers are not convinced that the conclusions are correct. Although the teeth are very similar to those of modern gorillas, they could have been shaped by [[parallel evolution]] of a genetically different species which consumed similar foods. "It is stretching the evidence to base a time scale for the evolution of the great apes on this new fossil. These structures appear on at least three independent lineages of apes, including gorillas, and they could relate to a dietary shift rather than indicating a new genetic trait," said Professor Peter Andrews at the [[Natural History Museum, London|Natural History Museum]] in [[London]], UK, who also added, "but the fossil evidence for the evolution of our closest living relatives, the great apes, is almost non-existent."<ref name="nhm">{{cite web|url= http://www.nhm.ac.uk/about-us/news/2007/august/news_12280.html |title=Ancient ape fossil found |date=2007-08-23 |accessdate=2007-08-28 |publisher=Natural History Museum |archive-url=https://web.archive.org/web/20120206205550/http://www.nhm.ac.uk/about-us/news/2007/august/news_12280.html |archive-date=2012-02-06 |url-status=dead}}</ref>

[[Paleoanthropology|Palaeoanthropologist]] Jay Kelley of the [[University of Illinois at Chicago]] was also skeptical. He remained unconvinced that it was a gorilla, saying that more work would need to be done to determine where this specimen may fit in [[Hominidae|hominid]] evolution. He said he would be "very cautious" about realigning divergence dates between species based on this specimen.<ref name="dalton" />

These teeth are collectively indistinguishable from those of modern gorilla subspecies in dental size and represented proportions. This modest sample nevertheless exhibits substantial size variation, with molars at both the largest and smallest end of the modern gorilla ranges of variation.


==See also==
==See also==
{{columns-list|colwidth=20em|
{{Div col}}
*[[Timeline of human evolution]]
* {{annotated link|Anoiapithecus|''Anoiapithecus''}}
* ''[[Afropithecus]]''
* {{annotated link|Dryopithecus|''Dryopithecus''}}
* ''[[Anoiapithecus]]''
* {{annotated link|Nakalipithecus|''Nakalipithecus''}}
* ''[[Danuvius guggenmosi|Danuvius]]''
* {{annotated link|Pierolapithecus|''Pierolapithecus''}}
* ''[[Dryopithecus]]''
* {{annotated link|Samburupithecus|''Samburupithecus''}}
* ''[[Graecopithecus]]''
{{div col end}}
* ''[[Hispanopithecus]]''
* ''[[Khoratpithecus]]''
* ''[[Lufengpithecus]]''
* ''[[Oreopithecus]]''
* ''[[Pierolapithecus]]''
* ''[[Sivapithecus]]''
}}


==Notes==
==References==
{{Reflist}}
{{Reflist}}

==References==
*Text originally used in this article was copied from the [[Wikinews]] article [[n:New fossils from 10 million year old ape found in Ethiopia|New fossils from 10-million-year-old ape found in Ethiopia]].


==External links==
==External links==
*{{Wikinews-inline|New fossils from 10 million year old ape found in Ethiopia}}
*{{Wikispecies-inline|Chororapithecus abyssinicus|''Chororapithecus abyssinicus''}}
*{{Wikispecies-inline|Chororapithecus abyssinicus|''Chororapithecus abyssinicus''}}
*[https://www.reuters.com/article/scienceNews/idUSL2263391820070822?feedType=RSS&feedName=scienceNews Researchers find fossils of 10 million-year-old ape] at [[Reuters]]
*[https://www.reuters.com/article/scienceNews/idUSL2263391820070822?feedType=RSS&feedName=scienceNews Researchers find fossils of 10 million-year-old ape] at [[Reuters]]

{{Portal bar|Evolutionary biology|Paleontology|Science}}
{{Haplorhini|Ho.}}
{{Taxonbar|from=Q133702}}
{{Taxonbar|from=Q133702}}

{{good article}}


[[Category:Fossil taxa described in 2007]]
[[Category:Fossil taxa described in 2007]]
[[Category:Miocene primates of Africa]]
[[Category:Miocene primates of Africa]]
[[Category:Monotypic primate genera|†Chlororapithecus]]
[[Category:Monotypic prehistoric primate genera]]
[[Category:Prehistoric apes]]
[[Category:Prehistoric apes]]
[[Category:Gorillas]]
[[Category:Gorillini]]
[[Category:Prehistoric primate genera]]

Latest revision as of 18:11, 6 November 2024

Chororapithecus
Temporal range: Tortonian, 8 Ma
↓
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Family: Hominidae
Subfamily: Homininae
Tribe: Gorillini
Genus: †Chororapithecus
Suwa et al., 2007
Species:
†C. abyssinicus
Binomial name
†Chororapithecus abyssinicus
Suwa et al., 2007

Chororapithecus is an extinct great ape from the Afar region of Ethiopia roughly 8 million years ago during the Late Miocene, comprising one species, C. abyssinicus. It is known from 9 isolated teeth discovered in a 2005–2007 survey of the Chorora Formation. The teeth are indistinguishable from those of gorillas in terms of absolute size and relative proportions, and it has been proposed to be an early member of Gorillini. However, this is controversial given the paucity of remains, and notable anatomical differences between Chororapithecus and gorilla teeth. The Kenyan ape Nakalipithecus has been proposed to be an ancestor of Chororapithecus or at least closely related. If correct, they would be the only identified fossil members of any modern non-human great ape lineage,[dubious – discuss] and would push the gorilla–human last common ancestor from 8 million years ago (identified by molecular analysis) to 10 million years ago. The teeth are adapted for processing tough plant fibres as well as hard, brittle food, and the formation is thought to represent a forested lakeside habitat.

Taxonomy

[edit]

Chororapithecus teeth were discovered in the Afar region, Ethiopia, in a 2005–2007 survey in the Beticha locality of the Chorora Formation, hence the name, and the formation itself is named after the Chorora village about 8 km (5.0 mi) south of the locality. The specific name, abyssinicus, is in reference to Abyssinia, the former name of Ethiopia. The ape was described in 2007 by anthropologists Gen Suwa, Reiko Kono, Shigehiro Katoh, Berhane Asfaw, and Yonas Beyene.[1]

Hominidae

Kenyapithecus

Nakalipithecus (as a stem hominid)

Homininae
Gorillini

Nakalipithecus (as a stem gorilla)

Chororapithecus

Gorillas

Hominini
Family tree showing Chororapithecus as a stem gorilla[2]

The remains represent at least 3, perhaps over 6, different individuals. The holotype specimen, CHO-BT 4, is a right upper second molar, and the paratypes are a left lower canine, 3 right upper third molars, a left lower third molar, a left lower first molar, and a left and a right lower molar fragment, making for a total of 9 isolated teeth. The discoverers noted the teeth have some of the same adaptations for shearing food as those of gorillas, and classified it as the first fossil member and the only other genus of the tribe Gorillini. Because the Chororapithecus teeth have several specializations not shared with those of gorillas (they exhibit a derived condition compared to the presumed last common ancestor, LCA), they did not consider it as ancestral to the gorilla.[1] However, the discovers also conceded it is possible that Chororapithecus and gorillas instead convergently evolved the same teeth due to a similar diet.[1] If Chororapithecus is not a gorillin, it may be a stem hominine[3] or not a hominine at all.[4]

The teeth were originally dated to 10.5–10 million years ago (mya), and the discoverers then concluded that the gorilla–human LCA existed about 12 mya, but they were re-dated to about 8 mya. If Chororapithecus was indeed a stem gorilla, the latter date is more consistent with the timing of 8 mya for the LCA according to molecular data. Based on the revised date and similarly large premolar size, the 10 million year old Kenyan Nakalipithecus has been proposed to have been the ancestor to Chororapithecus, which would move the LCA to 10 mya if correct.[2] Nonetheless, because there are so few remains known, its relations to modern great apes is unclear. It was the first extinct ape to have been proposed to be a member of the gorilla lineage.[5]

It is debated if great apes evolved in Africa or Eurasia given the abundance of early fossil apes species in the latter and the paucity in the former, despite all modern great apes except the orangutan being known from Africa. The first Miocene African great ape was discovered in 1997, Samburupithecus, and the only others known are Nakalipithecus and Chororapithecus. If Chororapithecus is indeed an early gorilla, then it would point to an African origin for great apes.[2][5] However, earlier Eurasian dryopithecines may be early hominines.[4]

Anatomy

[edit]

The teeth, both in absolute size and relative proportions, are the same as in gorillas, and the molars range in size between the largest and smallest of what is normally seen in adult gorillas. Like in gorillas, the upper molars have a long protocone crest, and the lower molars have a correspondingly long trigonid crest, which increase shearing efficacy. Compared to gorillas, the cusp tips are relatively peripheral, are not well pronounced, and the enamel is thicker especially at the side cusps where the tooth borders other teeth. This causes a wide basin on the middle of the molar.[1] This is reminiscent of the condition seen in Hominini (humans and chimpanzees).[3] The upper molars are elongated and narrow, and also have a gorilla-like enamel-dentine juncture.[1]

Palaeobiology

[edit]
The molars of Chororapithecus have similarities to those of a gorilla (visible above)

The teeth exhibit adaptations for shearing, but the low cusp height indicates the teeth likely folded and pulverised tough plant fibres rather than cut through them as gorillas and other folivores with higher cusps do. The thick enamel is more similar to that of orangutans, and may indicate the consumption of hard, brittle foods.[1] Orangutan molars are probably adapted for eating hard fruits and nuts.[6] Chororapithecus and Oreopithecus are the only known folivorous Miocene apes.[1]

The Chorora Formation represents a braided river system, possibly a forested area alongside a lake in a forest-savanna mosaic environment.[1] It is the only sub-Saharan vertebrate-bearing formation spanning from 9–7.4 mya, and records the earliest known occurrences of cercopithecine monkeys, hippos, and rabbits in Africa. At the Beticha locality, the large vertebrate assemblage is: colobine and cercopithecine monkeys, a hippo, the pig Nyanzachoerus, the antelope-like siveratheriine and Palaeotragus, a bosalephine antelope, wild cattle, the horse Cormohipparion and an unidentified equine, a rhino, what may be the elephant Stegotetrabelodon, a percrocutid hyena, and a large cat. Because horses and rodents are much less common in the Beticha locality than the type locality of the formation, Beticha may have been a comparatively more forested and closed environment.[7]

See also

[edit]

References

[edit]
  1. ^ a b c d e f g h Suwa, G.; Kono, R. T.; Katoh, S.; Asfaw, B.; Beyene, Y. (2007). "A new species of great ape from the late Miocene epoch in Ethiopia" (PDF). Nature. 448 (7156): 921–924. Bibcode:2007Natur.448..921S. doi:10.1038/nature06113. PMID 17713533. S2CID 4312331.
  2. ^ a b c Katoh, S.; Beyene, Y.; Itaya, T.; et al. (2016). "New geological and palaeontological age constraint for the gorilla–human lineage split". Nature. 530 (7589): 215–218. Bibcode:2016Natur.530..215K. doi:10.1038/nature16510. PMID 26863981. S2CID 205247254.
  3. ^ a b Schroer, K.; Wood, B. (2013). Anthropological Perspectives on Tooth Morphology: Genetics, Evolution, Variation. Cambridge University Press. pp. 183–184. ISBN 978-1-139-61950-9.
  4. ^ a b Begun, D. R. (2010). "Miocene Hominids and the Origins of the African Apes and Humans". Annual Review of Anthropology. 39: 77. doi:10.1146/annurev.anthro.012809.105047.
  5. ^ a b Dalton, Rex (2007). "Oldest gorilla ages our joint ancestor". Nature News. 448 (7156): 844–845. Bibcode:2007Natur.448..844D. doi:10.1038/448844a. PMID 17713490.
  6. ^ Kono, R. T. (2004). "Molar enamel thickness and distribution patterns in extant great apes and humans: new insights based on a 3-dimensional whole crown perspective". Anthropological Science. 112 (2): 121. doi:10.1537/ase.03106.
  7. ^ Suwa, G.; Beyene, Y.; Nakaya, H.; et al. (2015). "Newly discovered cercopithecid, equid and other mammalian fossils from the Chorora Formation, Ethiopia". Anthropological Science. 123 (1): 19–39. doi:10.1537/ase.150206.
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