Pseudoloricaria laeviuscula is the only species of the monotypic genus Pseudoloricaria, a genus of the family Loricariidae of catfish (order Siluriformes).[1] The phylogenetic position of Pseudoloricaria is uncertain.[1]
This species is endemic to Brazil where it is found in the middle and lower Amazon basin, including the Negro and Branco Rivers.[1] P. laeviuscula is found over sandy bottoms, in clear waters, in the main flow of rivers, and in neighboring temporary ponds.[1]
Pseudoloricaria laeviuscula reaches a length of 30.5cm (12inches) SL. Although reproductive habits are unknown, this species is probably a lip brooder.[1] Sexual dimorphism includes hypertrophied development of the lower lip suggesting that P. laeviuscula is a lip brooder.[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]