Urotrygon rogersi (Myliobatiformes: Urotrygonidae) from the subtropical, provides new biological, genetic, taxonomic, and distribution data for the genus Urotrygon

This study provides morphometric, genetic, taxonomic, and biogeographic information for Urotrygon rogersi (Jordan & Starks, 1895). A complete taxonomic identification was applied to 77 specimens of Urotrygon spp., which are housed and preserved in the two ichthyological collections of Baja California Sur (Mexico), and to 33 new fresh material specimens. Of all the 110 examined specimens, 48 were morphologically identified as U. rogersi. Of the latter, a subset of samples was selected for DNA taxonomy validation using NADH₂ and COI genes. Both mitochondrial markers successfully distinguished U. rogersi from other Urotrygonidae species. The NADH₂ specimens sequenced were identical to one available in the searched online databases. The biomaterial used from the latter is housed in the Biological Research and Teaching Collection (Texas, USA) and cataloged as Urotrygon simulatrix (Miyake & McEachran, 1988). Similarly, COI results showed identical sequences among this study and two Urotrygon sp. held in public databases. Both ichthyological collections assessed presented taxonomic misidentifications of U. rogersi. Which most frequently occurred for juvenile specimens, showing the taxonomic complexity of this group of batomorph fishes. Fifteen of the U. rogersi specimens studied were longer and broader than the maximum sizes previously reported for this species. The geographic distribution of U. rogersi was established between the marine ecoregion (ME) of the Magdalena Transition (Mexico) and Panama Bight (Colombia), with the Cortezian zone (Gulf of California) having the highest number of records. Conversely, the presence of U. simulatrix inhabiting Mexican waters is discarded. Similarly, Urotrygon aspidura (Jordan and Gilbert, 1882) spatial distribution may be restricted to the ME of the Mexican Tropical Pacific instead of Magdalena Transition and Cortezian. The new biological, taxonomic, genetic, and geographic distribution information in this study should be considered in any further evaluation regarding the conservation status of this endemic American round ray.