title: Two new species of Pseudancistrus (Siluriformes, Loricariidae) from the Amazon basin, northern Brazil.
abstract: Two new species of Pseudancistrus, a genus diagnosed by non-evertible cheek plates and hypertrophied odontodes along the snout margin, are described from two drainages of the Brazilian Shield: Pseudancistruskayabi from the rio Teles Pires (rio Tapajós basin) and Pseudancistrusasurini from the rio Xingu. The new species are distinguished from congeners (Pseudancistrusbarbatus, Pseudancistruscorantijniensis, Pseudancistrusdepressus, Pseudancistrusnigrescens, Pseudancistrusreus, and Pseudancistruszawadzkii) by the coloration pattern. Pseudancistruskayabi has dark bars on the dorsal and caudal fins which are similar to that of Pseudancistrusreus from the Caroní River, Venezuela. Pseudancistrusasurini is unique among Pseudancistrus in having whitish tips of the dorsal and caudal fins in juveniles to medium-sized adults.
authors.affiliation: Laboratório de Biologia e Genética de Peixes, Departamento de Morfologia, IB-UNESP, Campus de Botucatu, 18618-970, SP, Brazil.
authors.forename: Gabriel S C
authors.initials: GS
authors.lastname: Silva
authors.affiliation: Laboratório de Biologia e Genética de Peixes, Departamento de Morfologia, IB-UNESP, Campus de Botucatu, 18618-970, SP, Brazil.
authors.forename: Fábio F
authors.initials: FF
authors.lastname: Roxo
authors.affiliation: Laboratório de Biologia e Genética de Peixes, Departamento de Morfologia, IB-UNESP, Campus de Botucatu, 18618-970, SP, Brazil.
authors.forename: Claudio
authors.initials: C
authors.lastname: Oliveira
keywords: Ancistrini; Brazilian Shield; Neotropical fish; freshwater; taxonomy