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Updated: Jun 16, 2026
Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton
Published on: May 7, 2016
The histological structure of glyptosaurine osteoderms (Squamata: Anguidae), and the problem of osteoderm development
Vivian de Buffrénil1, Jean-Yves Sire, Jean-Claude Rage
1Département Histoire de la Terre, Muséum National d'Histoire Naturelle, UMR 7207 CNRS, Paris, France. vdebuff@mnhn.fr
Abstract:
Glyptosaurinae, a fossil clade of anguid lizards, possess robust osteoderms, with granular ornamentation. In this study, the structural and histological features of these osteoderms were described in order to reconstruct their developmental pattern and further document the degree of homology that could exist between vertebrate integumentary skeletons. Glyptosaurine osteoderms have a diploe architecture and display an unusually complex structure that includes four tissue types: a core of woven-fibered bone intensely remodeled; a peripheral formation of the same tissue containing dense bundles of long Sharpey fibers; a thick basal layer of lamellar bone; and a superficial layer of a non-osseous material that belongs to the category of hypermineralized tissues such as ganoine, or enameloid and enamel tissues. The growth pattern of glyptosaurine osteoderms involved appositional processes due to osteoblast activity. In early growth stages, osseous metaplasia might have also been involved, but this possibility is not substantiated by histological observations. The superficial layer of the osteoderms must have resulted from epidermal contribution, a conclusion that would support previous hypotheses on the role of epidermal-dermal interactions in the formation of squamate osteoderms.
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