Nerves of the Mandibular Musculature of the Sand Tiger Shark Carcharias taurus (Rafinesque, 1810) (Chondrichthyes: Odontaspididae) / Nervios de la Musculatura Mandibular del Tiburón Toro Carcharias taurus (Rafinesque, 1810) (Chondrichthyes: Odontaspididae)

ABSTRACT

During this study, fifteen shark heads of sand tiger shark Carcharias taurus (Rafinesque, 1810) were analyzed. The studied material was obtained in the Santos Fishing Terminal, São Paulo, Brazil. The heads dissection was focused on the characterization of the mandibular muscles and on the description of the mandibular branch of the trigeminal nerve. The C. taurus mandibular muscles are represented by m. preorbitalis, m. levator palatoquadrati, m. quadratomandibularis and m. intermandibularis. The origin of the trigeminal nerve of C. taurus is located in a lateral portion of the medulla oblongata. In the orbita, the trigeminal nerve branches off to originate the mandibular branch that innervates the muscles which are derived from the mandibular arch. The proximal branches of the trigeminal nerve mandibular branch innervate the m. levator palatoquadrati. The muscles preorbitalis and quadratomandibularis receive fibers from the intermediate branches of the trigeminal nerve mandibular branch and the distal ramification of the mandibular branch can be visualized in the m. intermandibularis.

RESUMEN

Fueron analizadas 15 cabezas de tiburón toro Carcharias taurus (Rafinesque, 1810), obtenidas en el Terminal Pesquero de Santos, São Paulo, Brasil. La disección permitió caracterizar los músculos mandibulares y describir la rama mandibular del nervio trigémino. Los músculos mandibulares de C. taurus son M. preorbitalis, M. levator palatoquadrati, M. quadratomandibularis y M. intermandibularis. El origen aparente del nervio trigémino de C. taurus está localizado en la porción lateral de la médula oblonga. En la órbita, las ramas del nervio trigémino salen para dar origen a la ramificación mandibular, la cual inerva a los músculos derivados del arco mandibular. Las ramificaciones proximales de la rama mandibular del nervio trigémino inervan al M. levator palatoquadrati. Los Mm. preorbitalis y quadratomandibularis reciben fibras de las ramas intermedias de la ramificación mandibular del nervio trigémino, y el M. intermandibularis recibe la ramificación distal de la rama mandibular del nervio trigémino.