Anatomía comparada del sistema digestivo de las rayas Urotrygon chilensis y Dasyatis sabina (Myliobatiformes)

Abstract

The general organization of the digestive system of the rays Urotrygon chilensis and Dasyatis sabina fits with the general morphological pattern of the Myliobatiformes. Dentition of both species shows sexual dimorphism, having the females flattened teeth whereas pointed teeth the males. Among the mandibular muscles, the adductor mandibulae is the most complex. Both the buccopharyngeal and the visceral cavities are dorsoventrally flattened. The esophagus is long, the stomach is U shaped, and the intestine is formed by the duodene, valvular intestine and rectum. The dorsal mesentery is restricted to the rectum and rectal gland. The main morphological characters differentiating both species are: the presence in U. chilensis of the cardiac sphincter and the S shape of the rectum, and the presence in D. sabina of mandibular notches and a higher number of coils of the valvular fold of the intestine. © Sociedad de Biología de Chile.