A 4.3-million-year-old Australopithecus anamensis mandible from Ileret, East Turkana, Kenya, and its paleoenvironmental context.

Autor: Lewis JE; Turkana Basin Institute, Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Chronicle Heritage, 319 E Palm Lane, Phoenix, AZ 85004, USA., Ward CV; Department of Pathology & Anatomical Sciences, University of Missouri, Columbia, MO 65212, USA. Electronic address: wardcv@missouri.edu., Kimbel WH; Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287-4101, USA., Kidney CL; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112-0112, USA., Brown FH; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112-0112, USA., Quinn RL; School of Earth, Environment & Society, Bowling Green State University, Bowling Green, OH 43403-0085, USA., Rowan J; Department of Archaeology, University of Cambridge, Cambridge, UK., Lazagabaster IA; National Research Center on Human Evolution (CENIEH), Paseo Sierra de Atapuerca 3, Burgos 09002, Spain; Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool L69 3BX, UK., Sanders WJ; Museum of Paleontology, University of Michigan, Ann Arbor, MI 48109-1085, USA., Leakey MG; Turkana Basin Institute, Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA., Leakey LN; Turkana Basin Institute, Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Department of Paleontology, National Museums of Kenya, Museum Hill, Nairobi, Kenya.
Jazyk: angličtina
Zdroj: Journal of human evolution [J Hum Evol] 2024 Sep; Vol. 194, pp. 103579. Date of Electronic Publication: 2024 Aug 21.
DOI: 10.1016/j.jhevol.2024.103579
Abstrakt: A hominin mandible, KNM-ER 63000, and associated vertebrate remains were recovered in 2011 from Area 40 in East Turkana, Kenya. Tephrostratigraphic and magnetostratigraphic analyses indicate that these fossils date to ∼4.3 Ma. KNM-ER 63000 consists of articulating but worn and weathered mandibular corpora, with a broken right M 2 crown and alveoli preserved at other tooth positions. Despite extensive damage, KNM-ER 63000 preserves diagnostic anatomy permitting attribution to Australopithecus anamensis. It can be distinguished from Australopithecus afarensis by its strongly inclined symphyseal axis with a basally convex, 'cut-away' external surface, a lateral corpus that sweeps inferomedially beneath the canine-premolar row, and alignment of the canine alveolus with the postcanine axis. KNM-ER 63000 is distinguished from Ardipithecus ramidus by its thick mandibular corpus and large M 2 crown. The functional trait structure and enamel's stable carbon isotopic composition of the Area 40 large-mammal community suggests an environment comparable to Kanapoi and other ∼4.5-4 Ma eastern African sites that would have offered Au. anamensis access to both C 3 and C 4 food resources. With an age of ∼4.3 Ma, KNM-ER 63000 is the oldest known specimen of Au. anamensis, predating the Kanapoi and Asa Issie samples by at least ∼100 kyr. This specimen extends the known temporal range of Au. anamensis and places it in temporal overlap with fossils of Ar. ramidus from Gona, Ethiopia. The morphology of KNM-ER 63000 indicates that the reconfigured masticatory system differentiating basal hominins from the earliest australopiths existed in the narrow temporal window, if any, separating the two. The very close temporal juxtaposition of these significant morphological and adaptive differences implies that Ar. ramidus was a relative rather than a direct phyletic ancestor of earliest Australopithecus.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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Databáze: MEDLINE
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