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The Postcranial Musculoskeletal System of Xenarthrans: Insights from over Two Centuries of Research and Future Directions

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Abstract

Xenarthrans stand out among mammals for various reasons, one of them being their musculoskeletal postcranial specializations. Extant armadillos, anteaters, and sloths feature archetypical adaptations to digging and/or diverse arboreal lifestyles. Numerous extinct xenarthrans dramatically depart in size and morphology from their extant relatives, which has sparked functional interpretations since the end of the eighteenth century. Here, we review the diverse methodological approaches that have been used to investigate functional aspects of the postcranial musculoskeletal system in extant and extinct xenarthrans. Specifically, we address qualitative and quantitative bone morphology (including geometric morphometrics), body size and allometry, bone inner structure, myology, as well as in vivo, ex vivo, and in silico experimentation. Finally, a short account is given on those analyses that included xenarthrans to gain insight into primate anatomy. This review helped to identify potential future directions for the functional analysis of the xenarthran anatomy, a tradition over two centuries old.

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Acknowledgements

Olivier Lambert is acknowledged for helping to recover a bibliographical reference. Cécile Colin-Fromont is thanked for providing the photograph of the glyptodonts formerly exhibited at the Muséum national d’Histoire naturelle (Paris, France). Steven Jasinsky, Nick Milne, Stephanie Pierce, Sergio Vizcaíno, and Néstor Toledo should receive our gratitude for allowing reproduction of figures from their articles. Susana Bargo is thanked for co-organizing the Xenarthran symposium at the International Congress of Vertebrate Morphology (2016), from which this article stems, and for improving the manuscript acting as Guest Editor. Two anonymous reviewers and the Editor, John Wible, are also acknowledged for their useful inputs. EA was funded by the Alexander von Humboldt Foundation.

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  1. Eli Amson and John A. Nyakatura contributed equally.

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  1. AG Morphologie und Formengeschichte, Institut für Biologie & Bild Wissen Gestaltung - ein interdisziplinäres Labor, Humboldt-Universität, Philippstraße 12/13, D-10115, Berlin, Germany

    Eli Amson & John A. Nyakatura

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Amson, E., Nyakatura, J.A. The Postcranial Musculoskeletal System of Xenarthrans: Insights from over Two Centuries of Research and Future Directions. J Mammal Evol 25, 459–484 (2018). https://doi.org/10.1007/s10914-017-9408-7

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