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Metacarpal trabecular architecture variation in the chimpanzee ( Pan troglodytes ): Evidence for locomotion and tool‐use?
Author(s) -
Lazenby Richard A.,
Skinner Matthew M.,
Hublin JeanJacques,
Boesch Christophe
Publication year - 2011
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.21390
Subject(s) - troglodytes , subspecies , anatomy , bipedalism , biology , head (geology) , geography , zoology , paleontology
Trabecular architecture was assessed by 3D micro‐computed tomography from spherical volumes of interest located within the head and base of metacarpals (MC) 1, 2, and 5 from n = 19 adult common chimpanzees. Two subspecies, West African Pan troglodytes verus from the Taï Forest, Côte d'Ivoire ( n = 12) and Central African P. t. troglodytes from Cameroon ( n = 7), were studied. For the combined sample, the metacarpal head is distinguished by greater bone volume fraction across all metacarpals, though the MC 1 is distinctive in having thicker, more plate‐like trabeculae. The architecture in the MC 2 and MC 5 can be related to strains associated with terrestrial knuckle‐walking. In particular, the relatively robust MC 5 head architecture may result from functional loading incurred during braking and use of a palm‐in hand posture. Examining differences between samples, we found that the Cameroon chimpanzees possess a more robust architecture across all metacarpals in the form of greater bone volume fraction, higher connectivity, and somewhat more plate‐like structure. These differences are not explicable in terms of population distinctions in body size or daily travel distance, but possibly reflect a combination of more terrestrial knuckle‐walking in the Cameroon sample and more diverse hand postures and precision handling required of nut‐cracking in West African chimpanzees. Am J Phys Anthropol, 2011. © 2010 Wiley‐Liss, Inc.