Publication Date:
2016-02-13
Description:
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 fossils. More recently, Chororapithecus abyssinicus, a probable primitive member of the gorilla clade, 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 nakayamai 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 thereafter. 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 x 10(-9) per site per year (refs 13 - 15).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Katoh, Shigehiro -- Beyene, Yonas -- Itaya, Tetsumaru -- Hyodo, Hironobu -- Hyodo, Masayuki -- Yagi, Koshi -- Gouzu, Chitaro -- WoldeGabriel, Giday -- Hart, William K -- Ambrose, Stanley H -- Nakaya, Hideo -- Bernor, Raymond L -- Boisserie, Jean-Renaud -- Bibi, Faysal -- Saegusa, Haruo -- Sasaki, Tomohiko -- Sano, Katsuhiro -- Asfaw, Berhane -- Suwa, Gen -- England -- Nature. 2016 Feb 11;530(7589):215-8. doi: 10.1038/nature16510.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Natural History, Hyogo Museum of Nature and Human Activities, Sanda 669-1546, Japan. ; Association for Conservation of Culture Awassa, PO Box 6686, Addis Ababa, Ethiopia. ; Centre francais des etudes ethiopiennes (CFEE), USR CNRS 3137, French Ministry for Foreign Affairs, PO Box 5554, Addis Ababa, Ethiopia. ; Research Institute of Natural Sciences, Okayama University of Science, Okayama 700-0005, Japan. ; Research Center for Inland Seas, Kobe University, Kobe 657-8501, Japan. ; Hiruzen Institute for Geology and Chronology, Okayama 703-8252, Japan. ; EES-14/MS D462, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA. ; Department of Geology and Environmental Earth Science, Miami University, 133 Culler Hall, Oxford, Ohio 45056, USA. ; Department of Anthropology, University of Illinois, Urbana, Illinois 61801, USA. ; Department of Earth and Environmental Sciences, Kagoshima University, Kagoshima 890-0065, Japan. ; Department of Anatomy, Howard University, Washington DC 20059, USA. ; Institut de Paleoprimatologie, Paleontologie Humaine : Evolution et Paleoenvironnements (IPHEP), UMR CNRS 7262, Universite de Poitiers, 86022 Poitiers, France. ; Museum fur Naturkunde - Leibniz Institute for Evolution and Biodiversity Science, Invalidenstrasse 43, 10115 Berlin, Germany. ; Institute of Natural and Environmental Sciences, University of Hyogo, Sanda 669-1546, Japan. ; The University Museum, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. ; Rift Valley Research Service, PO Box 5717, Addis Ababa, Ethiopia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26863981" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Ethiopia
;
*Fossils
;
Geologic Sediments/chemistry
;
*Gorilla gorilla/genetics
;
Humans
;
Mutation Rate
;
*Phylogeny
;
*Radiometric Dating
;
Time Factors
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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