Resumo

CHAVEZ-APONTE, Edwin Orlando et al. Histology and ultrastructure of the fossil osteoderms of glyptodon clavipes and holmesina sp. (xenarthra: cingulata). INCI [online]. 2008, vol.33, n.8, pp.616-619. ISSN 0378-1844.

This work is a structural analysis of the fossil osteoderms of Glyptodon clavipes (Glyptodontidae) and Holmesina sp. (Pampatheriidae) colected at the Muaco site (Colina Municipality, Falcon State, Venezuela). For the microanatomical study, the samples were observed under cross polarized light and scanning electronic microscopy. In Holmesina sp., the osteoderms of the anterior and posterior bucklers are hexagonal, composed of a single figure with the surface perforated by circular depressions of variable depths. In G. clavipes, most of the osteoderms are hexagonal and formed by a central figure with a small depression and defined by a central sulcus and surrounded by six to eight peripheral figures, separated from each other by radial sulci. At the microscopical level, the surface of the osteoderms of G. clavipes is texturized by a greater number of pits than in Holmesina sp. A histological section of a Holmesina osteoderm shows a superficial layer, integrated by mineralized fibers, and a deep area of compact bone perforated by vascular channels. In contrast, osteoderms of G. clavipes have a more extensive trabecular region with osteons and irregular resortion areas.

Palavras-chave : Cingulata; Glyptodon clavipes; Histología; Holmesina sp; Osteodermos.