In dorsal view, three other elements of the pectoral girdle can be observed: propterygium, mesopterygium and metapterygium.
In dorsal view, the pectoral girdle has three more elements: the propterygium, mesopterygium and metapterygium, the more variable of which is the mesopterygium articulating the other two.
The first one would include Urotrygon nana and Urotrygon munda, as their cranium shows reduced preorbital processes and nasal capsules slightly projected towards their ventral region, and the mesopterygium in the pectoral girdle is rounded.