Revista Chilena de Historia Natural 83 (3): 387-394, 2010
RESEARCH ARTICLE
Comparative anatomy of the digestive system of the skates, Urotrygon chilensis
and Dasyatis sabina (Myliobatiformes)
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.
Key words:
digestive tract, teeth,
visceral cavity, visceral musculature
