Lithoxancistrus Isbrücker, Nijssen & Cala, 1988 Pseudancistrus is a genus of suckermouth armored catfishes native to South America.

[1] Currently, there are 19 recognized species distributed in northern South America, with the inclusion of the genera Lithoxancistrus, the species formerly known as Hemiancistrus megacephalus, as well as the recently described Pseudancistrus corantijniensis.

[1] There is no single morphological feature which distinguishes the group from related genera.

This group comprises Guyanese derived Pseudancistrus bearing hypertrophied odontodes along the snout and nonevertible cheek plates.

[1] There is a considerable variation in size within this genus, up to over 20 cm in standard length, in the case of species such as P. pectegenitor.