Ancistrus cuiabae

Ancistrus cuiabae reaches a standard length of 11.5 cm (4.5 in). Ancistrus species develop soft, bushy tentacles on the snout when sexually mature, these are better developed in the males than they are in females.

Ancistrus cuiabae was formerly thought to be restricted to the Cuiabá River basin, in the upper portion of the Paraguay River drainage in Brazil, being considered to be endemic to the Pantanal region near Poconé. However, this species has also been recorded in the Miranda River system thus A. cuiabae is endemic to the upper Paraguay River system rather than only the Cuiabá system. A. cuiabae occurs in areas of turbid water, which develops a greenish coloration in the dry season as the nutrients concentrate, where there is a muddy substrate and depths ranging from 0.5 to 1.5 m (1 ft 8 in to 4 ft 11 in). It lives under the trunks and branches of submerged trees and in rocks, in environments with low or no current.

Ancistrus cuiabae is classified in the genus Ancistrus, a name coined by Rudolf Kner when he proposed the genus but Kner did not explain the etymology of the name. It is thought to be from the Greek ágkistron, meaning a "fish hook" or the "hook of a spindle", a reference to the hooked odontodes on the interopercular bone. The specific name, cuiabae, is a reference to the Cuiabá River basin, the basin this species is endemic to.