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

Abstract

Anatomía comparada del sistema digestivo de las rayas ABSTRACTThe 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.

Ecomorphology of the digestive tract of the brazilian electric ray Narcine brasiliensis (Olfers, 1831) (Torpediniformes: Narcinidae)

“…The presence of the cardiac sphincter, which function is to prevent gastric reflux, is less common in Chondrichthyies (Kobelkowsky 2010). Rays swallow the whole prey and use benthonic suction with highly movable mandibles.…”

Early Miocene chondrichthyans from the Culebra Formation, Panama: A window into marine vertebrate faunas before closure the Central American Seaway

“…Bigelow and Schroeder, 1953;Nordell, 1994;Kobelkowsky, 2010). Crowns are trapezoid and low in females and immature males teeth; and triangular and high in mature males.…”

Claves taxonomicas para el reconocimiento dentario en taxa del superorden Rajomorphii de Chile (Chondrichthyes, Batoidea)

“…Al respecto, se debe aclarar que ambas especies después de su primera descripción por sus respectivos autores (las cuales no consideran descripciones dentales), nunca más se tuvo registro de captura en aguas chilenas, en especial con U. marmoratus que además de no registrarse nuevas capturas en Chile, tampoco han habido registros en otras partes del mundo. En el caso de U. chilensis, recientemente se capturaron ejemplares en México (Kobelkowsky, 2010). Sin embargo, pese a la falta de material dentario de estas dos especies, como fueron descritas en Chile, se consideraron parte de la fauna batoidea chilena.…”