Dental sexual dimorphism and morphology of Urotrygon microphthalmum

摘要

Dental sexual dimorphism has been described for different species of batoids, and it has been suggested that this differentiation is advantageous to reproduction in most cases. The aim of the present study was to investigate the morphology of the dentition in the ray Urotrygon microphthalmum using scanning electron microscopy. The present study brings a detailed description of morphological characteristics in males and females during ontogenetic development. Dental sexual dimorphism was observed both in maturing and mature males, while females maintain the same crushing shape dentition during all development stages. The teeth modification in males corresponds to the onset of maturation, which occurs when the animal reaches approximately 171.7 mm in total length, indicating that this morphological modification is closely related to mating behavior-grasp females during copulation thus ensuring body attachment and clasper insertion during swimming.