Assessing the status of the KNM-ER 42700 fossil using Homo erectus neurocranial development.

Autor: Baab KL; Department of Anatomy, College of Graduate Studies, Midwestern University, Glendale, AZ, 85308, USA; NYCEP Morphometrics Group, New York, NY, 10016, USA. Electronic address: kbaab@midwestern.edu., Nesbitt A; Pathology and Anatomical Sciences, School of Medicine, University of Missouri, Columbia, MO, USA., Hublin JJ; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Collège de France, Paris, France., Neubauer S; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
Jazyk: angličtina
Zdroj: Journal of human evolution [J Hum Evol] 2021 May; Vol. 154, pp. 102980. Date of Electronic Publication: 2021 Mar 29.
DOI: 10.1016/j.jhevol.2021.102980
Abstrakt: Based on ontogenetic data of endocranial shape, it has been proposed that a younger than previously assumed developmental status of the 1.5-Myr-old KNM-ER 42700 calvaria could explain why the calvaria of this fossil does not conform to the shape of other Homo erectus individuals. Here, we investigate (ecto)neurocranial ontogeny in H. erectus and assess the proposed juvenile status of this fossil using recent Homo sapiens, chimpanzees (Pan troglodytes), and Neanderthals (Homo neanderthalensis) to model and discuss changes in neurocranial shape from the juvenile to adult stages. We show that all four species share common patterns of developmental shape change resulting in a relatively lower cranial vault and expanded supraorbital torus at later developmental stages. This finding suggests that ectoneurocranial data from extant hominids can be used to model the ontogenetic trajectory for H. erectus, for which only one well-preserved very young individual is known. However, our study also reveals differences in the magnitudes and, to a lesser extent, directions of the species-specific trajectories that add to the overall shared pattern of neurocranial shape changes. We demonstrate that the very young H. erectus juvenile from Mojokerto together with subadult and adult H. erectus individuals cannot be accommodated within the pattern of the postnatal neurocranial trajectory for humans. Instead, the chimpanzee pattern might be a better 'fit' for H. erectus despite their more distant phylogenetic relatedness. The data are also compatible with an ontogenetic shape trajectory that is in some regards intermediate between that of recent H. sapiens and chimpanzees, implying a unique trajectory for H. erectus that combines elements of both extant species. Based on this new knowledge, neurocranial shape supports the assessment that KNM-ER 42700 is a young juvenile H. erectus if H. erectus followed an ontogenetic shape trajectory that was more similar to chimpanzees than humans.
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.
(Copyright © 2021 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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