Planiloricaria cryptodon is the only species of the monotypic genus Planiloricaria, a genus of the family Loricariidae of catfish (order Siluriformes).[1]
This species is native to Bolivia, Brazil and Peru where it occurs in the upper Amazon basin, including the Ucayali, Purus, and Mamoré River drainages.[1] P. cryptodon inhabits sandy substrates in the main streams of large rivers.[1]
Planiloricaria cryptodon reaches a length of 21.5cm (08.5inches) SL. Although reproductive habits are unknown, this species is probably a lip brooder.[1] Sexual dimorphism is characterized by the shape of the genital area; the genital area in males is elongate and narrow compared with the large and roundish area of females.[1] This species shows derived features such as a reduction in size and number of teeth, premaxillary teeth absent, a circular head shape, and eyes reduced in size without iris operculum.[1]