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Morphological integration and shape covariation between the trapezium and first metacarpal among extant hominids

Bardo, Ameline, Dunmore, Christopher J., Cornette, Raphaël, Kivell, Tracy L. (2023) Morphological integration and shape covariation between the trapezium and first metacarpal among extant hominids. American Journal of Biological Anthropology, . ISSN 2692-7691. (doi:10.1002/ajpa.24800) (KAR id:101870)

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Objectives: The shape of the trapezium and first metacarpal (Mc1) markedly influence thumb mobility, strength, and the manual abilities of extant hominids. Previous research has typically focused solely on trapezium‐Mc1 joint shape. Here we investigate how morphological integration and shape covariation between the entire trapezium (articular and non‐articular surfaces) and the entire Mc1 reflect known differences in thumb use in extant hominids. Materials and Methods: We analyzed shape covariation in associated trapezia and Mc1s across a large, diverse sample of Homo sapiens (n = 40 individuals) and other extant hominids (Pan troglodytes, n = 16; Pan paniscus, n = 13; Gorilla gorilla gorilla, n = 27; Gorilla beringei, n = 6; Pongo pygmaeus, n = 14; Pongo abelii, n = 9) using a 3D geometric morphometric approach. We tested for interspecific significant differences in degree of morphological integration and patterns of shape covariation between the entire trapezium and Mc1, as well as within the trapezium‐Mc1 joint specifically. Results: Significant morphological integration was only found in the trapezium‐Mc1 joint of H. sapiens and G. g. gorilla. Each genus showed a specific pattern of shape covariation between the entire trapezium and Mc1 that was consistent with different intercarpal and carpometacarpal joint postures. Discussion: Our results are consistent with known differences in habitual thumb use, including a more abducted thumb during forceful precision grips in H. sapiens and a more adducted thumb in other hominids used for diverse grips. These results will help to infer thumb use in fossil hominins.

Item Type: Article
DOI/Identification number: 10.1002/ajpa.24800
Uncontrolled keywords: thumb, orangutans, African apes, morphological integration, trapeziometacarpal joint
Subjects: G Geography. Anthropology. Recreation > GN Anthropology
Divisions: Divisions > Division of Human and Social Sciences > School of Anthropology and Conservation
Funders: Fyssen Foundation (
European Research Council (
SWORD Depositor: JISC Publications Router
Depositing User: JISC Publications Router
Date Deposited: 18 Jul 2023 11:31 UTC
Last Modified: 19 Jul 2023 09:16 UTC
Resource URI: (The current URI for this page, for reference purposes)
Bardo, Ameline:
Dunmore, Christopher J.:
Cornette, Raphaël:
Kivell, Tracy L.:
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