Brazilian ichthyologists have described a new species of freshwater stingray from Peru that is very similar to the Otorongo ray (Potamotrygon falkneri).
Naming the new species Potamotrygon tatianae in the latest issue of the journal Papéis Avulsos de Zoologia, João Silva and Marcelo Carvalho distinguish it from congeners in having a colour pattern on the dorsal surface of the disc consisting of a relatively slender, highly convoluted, beige to dark brown worm-like pattern, a single row of dorsal tail spines, and a relatively longer tail behind the sting.
The new species is most similar to the Otorongo ray, but differs from it in having tail spines in one (instead of one to three) irregular row, fewer cartilaginous rays in the disc (90–93 vs. 94–100), a relatively longer tail, teeth in adult males without prominent cusps, and having spots on the dorsal surface of the disc that are all worm-like in shape and not circular, kidney-shaped or oval.
It additionally differs from the Otorongo ray in the features of the ventral lateral-line canal, dermal denticles and skull.
Potamotrygon tatianae is named after the late Tatiana Raso de Moraes Possato, an enthusiastic researcher of chondrichthyans, in particular potamotrygonids.
It is known from the Madre de Díos River, part of the upper Madeira River drainage in Peru.
For more information, see the paper: da Silva, JPCB & MR de Carvalho (2011) A new species of Neotropical freshwater stingray of the genus Potamotrygon Garman, 1877 from the Río Madre de Díos, Peru (Chondrichthyes: Potamotrygonidae). Papéis Avulsos de Zoologia 51, pp. 139–154.