Description of a new species of the catfish genus Trichomycterus (Teleostei: Siluriformes: Trichomycteridae) from the rio Paraiba do Sul basin, southeastern Brazil)

Trichomycterus maculosus, new species is described from the upper rio Paraiba do Sul basin, southeastern Brazil. It is hypothesized to be closely related to T. itatiayae, T. nigroaurants, and T. diabolus based on the presence of a broad metapterygoid, which is wider than deeper. Trichomycterus maculosus differs from all those three species by having 45 to 52 interopercular odontodes; distinguished from T. itatiayae and T. diabolus by having seven branchiostegal rays, and 17 to 18 opercular odontodes. It is also distinguished from T. itatiayae by having eight pectoral-fin rays, ten anal-fin rays, anal-fin origin in the vertical through the posterior portion of the dorsal-fin base, opercular and interopercular odontodes conical, caudal fin subtrucate, and color pattern exhibiting a dark gray row of blotches horizontally elongated along lateral midline of body; from T. nigroauratus, by having more slender head, narrower caudal peduncle, color pattern showing a dark gray row of blotches horizontally elongated along lateral midline of body, and by absence of golden stripes on the flank; and from T. diabolus, by having caudal fin subtruncate, absence of osseous articulation between metapterygoid and quadrate, presence of the pectoral-fin filament, and absence of unpigmented zone on proximal region of caudal fin.