title: Contributions to the tooth morphology in early embryos of three species of hammerhead sharks (Elasmobranchii: Sphyrnidae) and their evolutionary implications.
abstract: The tooth types in the embryos of the hammerhead sharks Sphyrna tiburo, Sphyrna tudes and Eusphyra blochii are here described in labial and lingual views, and, in some cases, in additional views. The presence of cusplets was observed in the anterior teeth of S. tiburo and S. tudes, which is secondarily lost after early embryonic stages. Many aligned root foramina were detected in the sphyrnids, which, as the cusplets, are shared by many phylogenetic-related carcharhinids. Other anatomic features, related to the root and central cusp, are presented for the first time. Such characters represent the first step to compare the teeth of extant and fossil species.
authors.affiliation: Departamento de Zoologia, Laboratório de Ictiologia, Tempo e Espaço, Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier, 524, CEP 20550-900 Maracanã, Rio de Janeiro, Brazil; Faculdade de Biologia, Centro Universitário Celso Lisboa, Rua Vinte e Quatro de Maio, 797, CEP 20950-092 Engenho Novo, Rio de Janeiro, Brazil. Electronic address: neymello.ictio@gmail.com.
authors.forename: Waldiney
authors.initials: W
authors.lastname: Mello
authors.forename: Paulo Marques Machado
authors.initials: PM
authors.lastname: Brito
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002965:Classification; D004625:Embryo, Nonmammalian / Q000648:ultrastructure; D005260:Female; D008297:Male; D009805:Odontogenesis; D012754:Sharks / Q000033:anatomy & histology / Q000196:embryology*; D013045:Species Specificity; D014070:Tooth / Q000196:embryology* / Q000648:ultrastructure
keywords: Dents; Embryonic; Embryonnaires; Morphologie; Morphology; Sphyrna; Sphyrnidae; Teeth