The first two species of South American freshwater stingrays of the genus Potamotrygon, reported from the Orinoco Basin of Colombia by François Roulin in 1829
by Tyson R. Roberts – aqua 26 (3-4) pp. 92-112
Pseudogobiopsis rubrimaculosus n. sp. is described from a freshwater stream in Sandaun Province, Papua New Guinea, on the basis of eight specimens, 16.6-24.2 mm SL. Diagnostic features include: second dorsal-fin elements I,7; anal-fin elements I,5-7 (modally 6); pectoral-fin rays 14-15 (modally 15), longitudinal scales 23-25 (modally 23); transverse scales (TRB) 7-8 (modally 7); predorsal scales 7-9 (modally 7), reaching to behind eyes;jaws enlarged in adult males; dorsal head pores and preopercular pores present; fourth dorsal spine longest, none elongate; pterygiophore formula 3-21210; generally tan with narrow brown scale outlines on upper body and double series of brownish to red-brown markings laterally on sides; dorsal and caudal fins with reddish spots, anal fin reddish, and pelvic fins blackish.