Aphanotorulus is a genus of armored catfishes native to the Amazon, Orinoco, Essequibo and Jaguaribe basins in South America.[1] They typically occur on a sand or gravel bottom in slow to moderately flowing rivers and streams,[2] but some species occur in areas with fast current.[3] The largest species in the genus reaches up to 51cm (20inches) in standard length.[2]
The taxonomy of this genus has been a matter of dispute, all having been placed in Hypostomus in the past, and some occasionally placed in Squaliforma. Squaliforma is now regarded as a synonym of Aphanotorulus, but species west of the Andes have been moved to Isorineloricaria.[1]
There are currently 7 recognized species of Aphanotorulus:[1] [3]
Of these species, the validity of A. phrixosoma is questionable, as the only known specimen likely is a hybrid between A. horridus and A. unicolor.[1]