Nine new species of Rineloricaria are described from upper and middle rio Uruguay basin in states of Rio Grande do Sul and Santa Catarina, Brazil. Rineloricaria misionera Rodriguez & Miquelarena, 2005 is the only species currently known from this basin. The new species are diagnosed mainly by abdominal plates arrangement, color pattern, extension of the anterior snout naked area, and fins length. The species described here are endemic to the rio Uruguay. Rineloricaria anitae and R. tropeira are restricted to the tributaries of the rio Canoas and the rio Pelotas; R. zaina is widely distributed from the confluence of the rio Canoas with the rio Pelotas to the rio Ibicuí; R. anhanguapitan is restricted to the rio Passo Fundo; R. capitonia occurs in the upper rio Ijuí; R. stellata is known from the rio Buricá, rio Ijuí, rio Piratini and rio Ibicuí; R. setepovos and R. reisi are described from the rio Piratini; and R. sanga is only known from the vicinity of Iraí. Comments on the fish diversity of the rio Uruguay and on the variation of abdominal plates in Rineloricaria are made.
Rineloricaria; Loricariidae; Uruguay river; taxonomy; Neotropical
