Dental anomalies in Caluromys (Marsupialia, Didelphimorphia, Didelphidae, Caluromyinae) and a reassessment of malformations in New World marsupials (Didelphimorphia, Microbiotheria and Paucituberculata)

Abstract

Dental anomalies have been documented in almost all mammalian orders, and include supernumerary or missing teeth, teeth with aberrant occlusal surfaces and/or roots and teeth in unusual positions. Our objectives were the description and categorization of dental anomalies in all species of the genus Caluromys. We studied 462 crania, recorded and classified dental anomalies in four categories: variations in occlusal/root morphology; teeth in unusual positions; supernumerary/missing teeth; presence of unshed deciduous premolars. We found anomalies in all species, with a percentage ranging from 11% to 6.3%. Caluromys derbianus produced anomalous M4/m4 and flipped crowns, the other two species produced higher numbers of missing teeth. We infer that flipped crowns might have consequences in mastication, while other anomalies seem to be less functionally important, especially those at the end of the toothrow. Comparisons with other New World marsupials show caluromyines have more anomalies in M4/m4 shape (similar to microbiotherids) and flipped crowns, while didelphids have more supernumerary teeth, and caenolestids have more missing teeth.