Topic
Chororapithecus
About: Chororapithecus is a research topic. Over the lifetime, 4 publications have been published within this topic receiving 260 citations.
Papers
TL;DR: The combined evidence suggests that Chororapithecus may be a basal member of the gorilla clade, and that the latter exhibited some amount of adaptive and phyletic diversity at around 10–11 Myr ago.
Abstract: Timing the divergence between the gorilla, chimp and human lineages has been the province of molecular phylogeny largely unconstrained by fossil evidence. Gen Suwa et al. now present fossil teeth from Ethiopia which look very similar to those of a modern gorilla, even though they are 10 million years old. If the teeth, assigned to a new species of fossil ape, are from a creature on the gorilla lineage, then the divergence between gorillas and the chimp–human stock must have happened before that time, constraining divergence dates reached through the comparison of contemporary genetic sequences. Fossil teeth from Ethiopia are presented that look very similar to those of a modern gorilla, despite being 10 million years old. If the teeth, assigned to a new species of fossil ape, come from a creature on the gorilla lineage, then the divergence between gorillas and the chimp–human stock must have happened before that time, constraining divergence dates reached through the comparison of contemporary genetic sequences. With the discovery of Ardipithecus, Orrorin and Sahelanthropus1,2,3,4,5,6,7, our knowledge of hominid evolution before the emergence of Pliocene species of Australopithecus8,9 has significantly increased, extending the hominid fossil record back to at least 6 million years (Myr) ago. However, because of the dearth of fossil hominoid remains in sub-Saharan Africa spanning the period 12–7 Myr ago, nothing is known of the actual timing and mode of divergence of the African ape and hominid lineages. Most genomic-based studies suggest a late divergence date—5–6 Myr ago and 6–8 Myr ago for the human–chimp and human–gorilla splits, respectively10,11,12,13,14—and some palaeontological and molecular analyses hypothesize a Eurasian origin of the African ape and hominid clade15,16. We report here the discovery and recognition of a new species of great ape, Chororapithecus abyssinicus, from the 10–10.5-Myr-old deposits of the Chorora Formation at the southern margin of the Afar rift. To the best of our knowledge, these are the first fossils of a large-bodied Miocene ape from the African continent north of Kenya. They exhibit a gorilla-sized dentition that combines distinct shearing crests with thick enamel on its ‘functional’ side cusps. Visualization of the enamel–dentine junction by micro-computed tomography reveals shearing crest features that partly resemble the modern gorilla condition. These features represent genetically based structural modifications probably associated with an initial adaptation to a comparatively fibrous diet. The relatively flat cuspal enamel–dentine junction and thick enamel, however, suggest a concurrent adaptation to hard and/or abrasive food items. The combined evidence suggests that Chororapithecus may be a basal member of the gorilla clade, and that the latter exhibited some amount of adaptive and phyletic diversity at around 10–11 Myr ago.
234 citations
Okayama University of Science1, Kobe University2, Los Alamos National Laboratory3, Miami University4, University of Illinois at Urbana–Champaign5, Kagoshima University6, Howard University7, Centre national de la recherche scientifique8, Museum für Naturkunde9, University of Hyogo10, University of Tokyo11
TL;DR: The Chorora evidence supports the hypothesis of in situ African evolution of the Gorilla–Pan–human clade, and is concordant with the deeper divergence estimates of humans and great apes based on lower mutation rates of ~0.5 × 10−9 per site per year.
Abstract: A substantial revision to the age of the Chorora Formation, Ethiopia, constraining the deposits to around 8 million years old and forming a revised age constraint for the human–gorilla lineage split. The Chorora Formation, at the southern margin of the Afar rift in Ethiopia, has been regarded as providing a fossil record approximately 10.5 million years old. In 2007, Gen Suwa et al. reported the discovery of a fossil relative of the gorilla in the Chorora Formation. Thought to have been between 10 and 10.5 million years old, Chororapithecus abyssinicus was seen a primitive member of the gorilla clade. Now Suwa and colleagues report new field observations, geochemical, magnetostratigraphic and radioisotopic data, consistent with a substantial revision of the age of the Chorora Formation to around 8 million years old. This lifts Chororapithecus from a time when apes were common in Eurasia, to one in which evidence for fossil apes is scarce. The attribution to the gorilla lineage looks all the more important as it helps constrain the split between gorillas and the lineage leading to hominins and chimpanzees, and suggests that this split occurred in Africa. The palaeobiological record of 12 million to 7 million years ago (Ma) is crucial to the elucidation of African ape and human origins, but few fossil assemblages of this period have been reported from sub-Saharan Africa. Since the 1970s, the Chorora Formation, Ethiopia, has been widely considered to contain ~10.5 million year (Myr) old mammalian fossils1,2,3,4,5,6,7. More recently, Chororapithecus abyssinicus, a probable primitive member of the gorilla clade6, was discovered from the formation. Here we report new field observations and geochemical, magnetostratigraphic and radioisotopic results that securely place the Chorora Formation sediments to between ~9 and ~7 Ma. The C. abyssinicus fossils are ~8.0 Myr old, forming a revised age constraint of the human–gorilla split. Other Chorora fossils range in age from ~8.5 to 7 Ma and comprise the first sub-Saharan mammalian assemblage that spans this period. These fossils suggest indigenous African evolution of multiple mammalian lineages/groups between 10 and 7 Ma, including a possible ancestral-descendent relationship between the ~9.8 Myr old Nakalipithecus nakayamai8 and C. abyssinicus. The new chronology and fossils suggest that faunal provinciality between eastern Africa and Eurasia had intensified by ~9 Ma, with decreased faunal interchange thereafter9,10,11,12. The Chorora evidence supports the hypothesis of in situ African evolution of the Gorilla–Pan–human clade, and is concordant with the deeper divergence estimates of humans and great apes based on lower mutation rates of ~0.5 × 10−9 per site per year (refs 13, 14, 15).
53 citations
1 Jan 2016
TL;DR: This paper investigated both the morphology and the environment of a group of hominids that have been published as early human ancestors but which have only been mentioned in passing so far in this account.
Abstract: I am attempting several things in this chapter. In the first place we must consider the environments associated with the fossil apes described in the previous chapter, although for some of them there is little information. I am then going to go straight on to investigate both the morphology and the environment of a group of hominids that have been published as early human ancestors but which have only been mentioned in passing so far in this account. I am making no judgement about whether or not they are on the human lineage, but they are included in this chapter to produce a measure of continuity between them and their fossil ape precursors. They are all important in the tracing of the common ancestor of apes and humans, and the one thing that all can agree on is that they are close to the ape/human common ancestor, either as descendants or as precursors. The only disagreement comes when a decision has to be made as to which side of the common ancestor they fall: on the human or hominin lineage after it has split off from the apes; or on the hominid lineage preceding the split. Before discussing the environments associated with them, it is necessary to consider some of the morphologies present on these fossils, both to show how they were adapted to the environment and to extract characters that may have been important in the common ancestry of apes and humans. The environment in the late Miocene The site at Beticha from which Chororapithecus abyssinicus was found occurs relatively late in the Chorora Formation and has a rather different animal fauna from that present in the lower deposits. The sediments formed in a braided river system with palaeosol formation, and the sparse fauna includes a monkey species as well as the fossil ape. There is, however, almost no information on the likely palaeoenvironment present at that time. Similarly, the site at Nakali with fragmentary remains of Nakalipithecus nakayamai has little information on environment. The deposits come from a volcanic mudflow in the upper member of the Nakali Formation, suggesting rapid sediment accumulation. The animal fauna is similar to that of the Samburu Hills site (see below), and it includes several other primate species. It is said to resemble the southern Eurasian faunas linked with evergreen woodland.
TL;DR: The relative abundance of Eurasian apes between 12.5 and 8 Ma—in contrast to a dearth of African apes during the same chronologic interval—has led some investigators to suggest that the African ape–human clade evolved from a Eurasian ancestor, specifically, a previously undescribed and unnamed ape from Turkey.
Abstract: The relative abundance of Eurasian apes between 12.5 and 8 Ma—in contrast to a dearth of African apes during the same chronologic interval—has led some investigators (1, 2) to suggest that the African ape–human clade evolved from a Eurasian ancestor, specifically, a previously undescribed and unnamed ape from Turkey (3). In the last several weeks, three new ape genera have been reported, one from Turkey (Ouranopithecus turkae), one from Ethiopia (Chororapithecus abyssinicus), and the latest, Nakalipithecus nakayamai, from Kenya, which is the subject of the article by Kunimatsu et al. (4) in a recent issue of PNAS.
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2016 | 2 |
| 2007 | 2 |