Hyperossification in miniaturized toadlets of the genus Brachycephalus (Amphibia: Anura: Brachycephalidae): Microscopic structure and macroscopic patterns of variation |
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| Authors: | Rute B.G. Clemente‐Carvalho Marta M. Antoniazzi Carlos Jared Célio F.B. Haddad Ana C.R. Alves Henrique S. Rocha Gabriela R. Pereira Davi F. Oliveira Ricardo T. Lopes Sergio F. dos Reis |
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| Affiliation: | 1. Programa de Pós‐Gradua??o em Genética e Biologia Molecular, Universidade Estadual de Campinas, 13083‐970 Campinas, S?o Paulo, Brazil;2. Laboratório de Biologia Celular, Instituto Butantan, 05503‐900 S?o Paulo, S?o Paulo, Brazil;3. Departamento de Zoologia, Universidade Estadual Paulista, 13506‐900 Rio Claro, S?o Paulo, Brazil;4. Laboratório de Instrumenta??o Nuclear, Universidade Federal do Rio de Janeiro, 21945‐970 Rio de Janeiro, Rio de Janeiro, Brazil;5. Departamento de Parasitologia, Universidade Estadual de Campinas, 13083‐970 Campinas, S?o Paulo, Brazil |
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| Abstract: | Species of the genus Brachycephalus, have a snout‐vent length of less than 18 mm and are believed to have evolved through miniaturization. Brachycephalus ephippium, is particularly interesting; because its entire skull is hyperossified, and the presacral vertebrae and transverse processes are covered by a dorsal shield. We demonstrate in this paper that, at the macroscopic level, a completely hyperossified skull and dorsal shield occur only in B. ephippium, but not in B. ferruginus, B. izechsohni, B. pernix, B. pombali, B. brunneus, B. didactylus, and B. hermogenesi. An intermediate condition, in which the skull is hyperossified but a dorsal shield is absent, occurs in B. vertebralis, B. nodoterga, B. pitanga, and B. alipioi. The microscopic structure of hyperossification was examined in skulls of B. ephippium and B. pitanga, revealing a complex organization involving the presence of Sharpey fibers, which in humans are characteristic of periodontal connections. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc. |
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| Keywords: | miniaturization skeletal morphology Sharpey fibers anura skull morphology |
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