A new Trichomycterus lacking pelvic fins and pelvic girdle with a very restricted range in Southern Brazil (Siluriformes: Trichomycteridae)

Trichomycterus tropeiro, new species, is described from the headwaters of the rio das Antas, laguna dos Patos system, Southern Brazil. Trichomycterus tropeiro is distinguishable from other species of the genus by the absence of pelvic fins and pelvic girdle, except from Trichomycterus candidus and Trichomycterus catamarcensis. It differs from these two species in several counts and measurements. The apparent endemism of the species is discussed.