Cases of dental agenesis, supernumerary teeth and dental losses are presented in three species of South American Otariids: Arctocephalus australis (Zimmermann, 1783), A. tropicalis (Gray, 1872) and Otaria flavescens (Shaw, 1800). For the first time, congenital and acquired dental anomalies were comparatively diagnosed in skull samples from southern Brazil and nearby areas. The skulls and mandibles were accessed in the scientific collection of mammals of the Federal University of Santa Catarina, southern Brazil. Agenesis was found only among maxillary post-canine teeth, especially the distal ones (PC/6), due to an evolutionary trend towards reduction of the number of post-canine teeth in this family. Maxillary and mandibular supernumerary teeth were found in A. australis and A. tropicalis, but their positioning is unrelated to cases regarding phylogenetic and evolutionary implications. Dental losses were found in all species and different stages of alveolar obliteration suggest that this process is common in Otariids and does not affect their survival. The investigation of congenital and acquired dental anomalies in pinnipeds can provide information on dental formula evolution in Pinnipeds and in the phylogenetic relationships among Carnivora.

Este estudo caracteriza a ultramorfologia da nervura estridulatória e o som de chamado de duas populações de Eneoptera surinamensis (De Geer, 1773) de Foz do Iguaçu, Paraná e Rio Claro, São Paulo, distantes cerca de mil quilômetros. Os dentes que compõem a nervura estridulatória têm forma de concha, os maiores presentes na região mediana da fileira, reduzindo gradualmente de tamanho em direção às extremidades. Os espécimes de Foz do Iguaçu têm a nervura estridulatória com 1,89 mm ± 0,15 de comprimento, 82 ±9,8 dentes, sendo 43,76 ± 5,94 (n=15) por milímetro, enquanto os de Rio Claro 1,96 ± 0,19 mm de comprimento, 87 ± 9,81 dentes e 44,52 ± 4,61 dentes por mm (n=15). As diferenças observadas entre as populações não são estatisticamente significantes. O som de chamado é composto por um trill contínuo que alterna dois conjuntos de notas, com padrões temporais distintos.

This study characterizes the calling song and ultramorphology of the stridulatory file of two geographically isolated populations of the tropical bush cricket Eneoptera surinamensis (De Geer, 1773) from city of Foz do Iguaçu, state of Paraná, and town of Rio Claro, state of São Paulo, Brazil, distant 1,000 Km from each other. The teeth are shell-shaped, the larger ones are distributed in the medium region of the file, decreasing gradually in size towards the edges. Specimens from Foz do Iguaçu have a file with 82 ± 9.8 teeth, length=1.89 mm ± 0.15 with 43.76 ± 5.94 teeth per mm (n=15). Specimens from Rio Claro present a file with 87 ± 9.81, length=1.96 ± 0.19 mm with 44.52 ± 4.61 teeth per mm (n=15). Statistical differences found between the two populations are not significant. The calling song is an uninterrupted trill that alternates two sets of notes distinct for its temporal features.