Mónica González-Isáis & Héctor Marcos Montes-Domínguez

Works conducted on batoids have revealed large variations in the musculature of the ventral cephalic region, associated to the different lifestyles of these organisms and, therefore, to their feeding mechanisms. This work aimed to conduct a comparative study of the dorsal and ventral cephalic muscular morphology of two species of the family Narcinidae: Narcine vermiculatus and Diplobatis ommata. It was observed that both species share a common morphological pattern. Muscles with larger variations in the dorsal region were the rostral depressor, the late- ral preorbital and the rostral elevator. The most relevant difference in this region between both species was the absence of the cucularis muscle in D. ommata. In the ventral region, the main differences were observed in the mandibular depressor, medial preorbital, interbranchial and hyomandibular depressor muscles. In D. ommata, the latter is formed by two packages, and by one in N. vermiculatus. It can be concluded that the cephalic musculature is constant; however, significant differences are observed in the muscle development degree in both the dorsal and the ventral regions.

KEY WORDS: Elasmobranchii; Narcinidae; Cephalic musculature; Cranial musculature.

GONZÁLEZ-ISÁIS, MÓNICA & MONTES-DOMÍNGUEZ, H. M. Morphological variation in the cephalic musculature of Diplobatis ommata and Narcine vermiculatus (Chondrychthyes: Narcinidae). Int. J. Morphol., 41(5):1304-1309, 2023.