Skeleton of batoids has been important to outline kinship relations in this group. Therefore, the objective of this work is describing the anatomy of five species of genus Urotrygon. Skeleton of Urotrygonids displayed a common morphological pattern, with the following differences: 1) preorbital processes are reduced in Urotrygon nana and Urotrygon munda, and developed on all other species; 2) the first postorbital process is reduced in U. nana and U. munda; 3) the first hypobranchial cartilage is fragmented only in Urotrygon rogersi; 4) only Urotrygon aspidura had a bridge in the basibranchial cartilage; lateral processes of the synarcuale in U. aspidura are long and thin, while short and wide in U. nana and U. rogersi; 6) U. nana has only one single fenestra in its pectoral girdle, while other species have two; 7) In U. nana and U. munda the mesopterygium is rounded, but in all other species it is elongated in its anterior part; 8) U. nana y U. munda have a more arched pelvic girdle. Species with more plesiomorphic characters are U. nana and U. munda.
KEY WORDS: Batoids; Urotrygonidae; Urotrygon; Neurocranium; Skeleton.
