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Article Dans Une Revue Journal of Anatomy Année : 2010

Vertebral microanatomy in squamates: structure, growth and ecological correlates.

Alexandra Houssaye
Arnaud Mazurier
Anthony Herrel
Virginie Volpato
  • Fonction : Auteur

Résumé

The histological study of vertebrae in extant squamates shows that the internal vertebral structure in this group differs from that of other tetrapods. Squamate vertebrae are lightly built and basically composed of two roughly concentric osseous tubes--one surrounding the neural canal and the other constituting the peripheral cortex of the vertebra--connected by few thin trabeculae. This structure, which characteristically evokes that of a tubular bone, results from a peculiar remodelling process characterised by an imbalance between local bone resorption and redeposition; in both periosteal and endosteo-endochondral territories, bone is extensively resorbed but not reconstructed in the same proportion by secondary deposits. This process is particularly intense in the deep region of the centrum, where originally compact cortices are made cancellous, and where the endochondral spongiosa is very loose. This remodelling process starts at an early stage of development and remains active throughout subsequent growth. The growth of squamate centra is also strongly asymmetrical, with the posterior (condylar) part growing much faster than the anterior (cotylar) part. Preliminary analyses testing for associations between vertebral structure and habitat use suggest that vertebrae of fossorial taxa are denser than those of terrestrial taxa, those in aquatic taxa being of intermediate density. However, phylogenetically informed analyses do not corroborate these findings, thus suggesting a strong phylogenetic signal in the data. As our analyses demonstrate that vertebrae in snakes are generally denser than those of lizards sensu stricto, this may drive the presence of a phylogenetic signal in the data. More comprehensive sampling of fossorial and aquatic lizards is clearly needed to more rigorously evaluate these patterns.

Domaines

Paléontologie

Dates et versions

hal-00591875 , version 1 (10-05-2011)

Identifiants

Citer

Alexandra Houssaye, Arnaud Mazurier, Anthony Herrel, Virginie Volpato, Paul Tafforeau, et al.. Vertebral microanatomy in squamates: structure, growth and ecological correlates.. Journal of Anatomy, 2010, 217 (6), pp.715-27. ⟨10.1111/j.1469-7580.2010.01307.x⟩. ⟨hal-00591875⟩
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