Potamotrygon Identification: Confusion?!?!

Taxonomic work on the family is constrained by the fact that many species of Potamotrygon are poorly described, lack adequate material, or present much intraspecific variation in coloration. This is compounded by generally overlapping meristic and morphometric features among species of Potamotrygon (both other genera are monotypic). Therefore, the approach adopted here has been to not recognize certain species that are inadequately defined at present, or that lack adequate material for proper characterization. Due to Potamotrygon being polymorphic, the identification confusion has become increasingly abundant.

Natural Hybridization has been suggested, but with no physical proof of genetic testing and/or DNA testing, we will never have solid results.  Many potamotrygon have been synonymized with each other, and or mis-identified through improper or uneducated literature.  The collection area and or locus typicus can play a major factor in the identification.

A holotype is a single physical example (or illustration) of an organism, known to be used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several such, but explicitly designated as the holotype.  The problem with holotypes involving potamotrygons, is the collection data is very old, vague, and unclear.  At that time, their knowledge of the polymorphism in stingrays was little known, and many new species were created based on unclear information.

The issue of mis-identification is handed down from the Fisherman, to Collectors, to Exporters, to Importers, and to Wholesalers.. and Finally, your local fish store will sell whatever they are told the species is.  Sadly, most times the identification is incorrect.

Here are some Scientific Identification Tools

"sp." = Species ~ Following the genus name, this represents lack of scientific description and has not yet been formally described.

"cf." = Compare ~ In front of the species name, this represents a species variations or population to have altered traits, but these traits do not justify placing them in a species group of their own.

"sp. aff." = Similar To ~ In front of the species name, this represents a species that is un-identified, but very similar to that named.