A new species of Pareiorhina is described from the Ribeirão Grande and adjacent drainages, in the left bank of the Rio Paraíba do Sul basin, in São Paulo State, southeastern Brazil. Pareiorhina brachyrhyncha is uniquely diagnosed among its congeners by the reduction or absence of azygous plates in front of the nuchal plate. It also differs from its congeners by the presence of a minute lateral cusp in the teeth, wider body, anterior and lateral profile of head rounded, broad distal profile of the paired fins, and lower number of vertebrae. The species is considered to be closely related to the sympatric P. rudolphi, based on the lack of azygous dorsal plates above the caudal peduncle.