Potamotrygon tigrina, a new species of freshwater stingray from the upper Amazon basin
Published on 21. April 2011
Marcelo R. de Carvalho, Mark H. Sabaj Perez, Nathan R. Lovejoy
ABSTRACT:
A new species of Neotropical freshwater stingray, family Potamotrygonidae, is described from the Río Nanay in the upper Río Amazonas basin of Peru. Potamotrygon tigrina, n. sp., is easily distinguished from all congeners by its conspicuous dorsal disc coloration, composed of bright yellow to orange vermiculations strongly interwoven with a dark-brown to deep-black back-ground. Additional features that in combination diagnose P. tigrina, n. sp., include the presence of a single angular cartilage, low and not closely grouped dorsal tail spines, and coloration of tail composed of relatively wide and alternating bands of creamy white and dark brown to black. Potamotrygon tigrina is closely related to Potamotrygon schroederi Fernandez-Yépez, 1958, which occurs in the Rio Negro (Brazil) and Río Orinoco (Venezuela, Colombia). Both species are very similar in propor-tions and counts, and share features hypothesized to be derived within Potamotrygonidae, related to their specific angular carti-lage morphology, distal tail color, dorsal tail-spine pattern, and ventral lateral-line system. To further substantiate the description of P. tigrina, n. sp., we provide a redescription of P. schroederi based on material from the Rio Negro (Brazil) and Río Orinoco (Venezuela). Specimens from the two basins differ in number of vertebral centra and slightly in size and frequency of rosettes on dorsal disc, distinctions that presently do not warrant their specific separation. Potamotrygon tigrina is frequently commercialized in the international aquarium trade but virtually nothing is known of its biology or conservation status.
Zootaxa 2827: 1–30 (2011)