Dental morphology and microstructure of the Prickly DogfishOxynotus bruniensis(Squaliformes: Oxynotidae)

This study describes and illustrates the jaws, teeth, and tooth microstructure of the Prickly DogfishOxynotus bruniensis. Detailed accounts of the dental morphology ofO. bruniensisare rare and have not addressed the tissue arrangement or microstructure of the teeth. These features are documented and discussed in the contexts of interspecific comparisons with other elasmobranchs and the dietary specialization ofO. bruniensis. The overall tooth morphology ofO. bruniensisis similar to those of other closely related members in the order Squaliformes, as is the tissue arrangement, or histotype.Oxynotus bruniensisexhibits a simplified enameloid microstructure, which we compare with previously documented enameloid microstructures of other elasmobranchs. Though subtle interspecific differences in dental characters are documented, neither overall tooth morphology nor histotype and microstructure are unique toO. bruniensis. We conclude that in the case ofO. bruniensis, dietary specialization is facilitated by behavioral rather than morphological specialization.