title: Hyperossification in miniaturized toadlets of the genus Brachycephalus (Amphibia: Anura: Brachycephalidae): Microscopic structure and macroscopic patterns of variation.
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.
authors: Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Estadual de Campinas, 13083-970 Campinas, São Paulo, Brazil.
authors: Rute B G
authors: RB
authors: Clemente-Carvalho
authors: Marta M
authors: MM
authors: Antoniazzi
authors: Carlos
authors: C
authors: Jared
authors: Célio F B
authors: CF
authors: Haddad
authors: Ana C R
authors: AC
authors: Alves
authors: Henrique S
authors: HS
authors: Rocha
authors: Gabriela R
authors: GR
authors: Pereira
authors: Davi F
authors: DF
authors: Oliveira
authors: Ricardo T
authors: RT
authors: Lopes
authors: Sergio F
authors: SF
authors: Dos Reis
mesh_terms: D000818:Animals; D001001:Anura / Q000033:anatomy & histology / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010012:Osteogenesis / Q000502:physiology*; D012886:Skull / Q000502:physiology / Q000648:ultrastructure; D013045:Species Specificity; D013131:Spine / Q000502:physiology / Q000648:ultrastructure; D017356:Synchrotrons