A microanatomical and histological study of the fin long bones of the Devonian sarcopterygian Eusthenopteron foordi

Authors

  • François J. Meunier,

    1. UMR CNRS 7208 -IRD-University P.M. Curie, BOREA, Département des Milieux et peuplements aquatiques, Muséum national d’Histoire naturelle, C.P. 26, 43 rue Cuvier, 75231 Paris Cedex 05, France
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  • Michel Laurin

    1. UMR 7207 CNRS/MNHN/UPMC, “Centre de Recherches sur la Paléobiodiversité et les Paléoenvironnements”, Muséum National d’Histoire Naturelle, Bâtiment de Géologie, C P 48, 43 rue Buffon, F-75231 Paris Cedex 05 France
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Michel Laurin, UMR 7207 CNRS/MNHN/UPMC, “Centre de Recherches sur la Paléobiodiversité et les Paléoenvironnements”, Muséum National d’Histoire Naturelle, Bâtiment de Géologie, C P 48, 43 rue Buffon, F-75231 Paris Cedex 05 France. E-mail: michel.laurin@upmc.fr

Abstract

Meunier F.J. and Laurin M. 2012. A microanatomical and histological study of the fin long bones of the Devonian sarcopterygian Eusthenopteron foordi. —Acta Zoologica (Stockholm) 93: 88–97.

A paleohistological study of the endoskeletal bones of the dorsal and pelvic fins shows that Eusthenopteron foordi had true long bones that grew in length and thickness through endochondral and periosteal ossification, respectively. Endochondral ossification required cartilaginous epiphyses with a growth plate system whose presence is confirmed by both calcified cartilage and thin endochondral bony trabeculae that overlaid the erosive bays located in hypertrophic calcified cartilage. Articulations between axial mesomeres in paired fins were diarthroses. This microanatomical organization, i.e. longitudinal growth of diaphysis and articulations between epiphyses, can be considered an exaptation for terrestrial locomotion as it can produce skeletal elements able to support strong mechanical stress.

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