A geometric morphometric approach to investigate primate proximal phalanx diaphysis shape
Wennemann, Sophie E. (University of Southern California. Department of Integrative Anatomical Sciences)
Lewton, Kristi L. (University of Southern California. Department of Biological Sciences)
Orr, Caley M. (University of Colorado Denver. Department of Anthropology)
Almécija, Sergio (Institut Català de Paleontologia Miquel Crusafont)
Tocheri, Matthew W. (University of Wollongong. Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage)
Jungers, William L. (Association Vahatra (Madagascar))
Patel, Biren A. (University of Southern California. Department of Biological Sciences)

Date:	2022
Abstract:	Current approaches to quantify phalangeal curvature assume that the long axis of the bone's diaphysis approximates the shape of a portion of a circle (included angle method) or a parabola (second-degree polynomial method). Here we developed, tested, and employed an alternative geometric morphometrics-based (GM) approach to quantify diaphysis shape of proximal phalanges in humans, apes and monkeys with diverse locomotor behaviors. One hundred landmarks of the central longitudinal axis were extracted from 3D surface models and analyzed using 2DGM methods, including generalized Procrustes analyses. Principal components analyses were performed and PC1 scores (>80% of variation) represented the dorsopalmar shape of the bone's central longitudinal axis and separated taxa consistently and in accord with known locomotor behavioral profiles. The most suspensory taxa, including orangutans, hylobatids and spider monkeys, had significantly lower PC1 scores reflecting the greatest amounts of phalangeal curvature. In contrast, bipedal humans and the quadrupedal cercopithecoid monkeys sampled (baboons, proboscis monkeys) exhibited significantly higher PC1 scores reflecting flatter phalanges. African ape (gorillas, chimpanzees and bonobos) phalanges fell between these two extremes and were not significantly different from each other. PC1 scores were significantly correlated with both included angle and the a coefficient of a second-degree polynomial calculated from the same landmark dataset, but had a significantly higher correlation with included angles. Our alternative approach for quantifying diaphysis shape of proximal phalanges to investigate dorsopalmar curvature is replicable and does not assume a priori either a circle or parabola model of shape, making it an attractive alternative compared with existing methodologies.
Grants:	Agencia Estatal de Investigación PID2020-116908GB-I00
Note:	Altres ajuts: CERCA Programme/Generalitat de Catalunya
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Curvature ; Geometric morphometrics ; Included angle ; Phalanx ; Suspensory
Published in:	American Journal of Biological Anthropology, Vol. 177, Issue 3 (March 2022) , p. 581-602, ISSN 2692-7691

DOI: 10.1002/ajpa.24460
PMID: 35755956

Postprint 68 p, 1.6 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Institut Català de Paleontologia Miquel Crusafont (ICP)
Articles > Research articles
Articles > Published articles