Two new species of Pseudancistrus (Siluriformes, Loricariidae) from the Amazon basin, northern Brazil.

Fábio F Roxo,Gabriel S C Silva,Claudio Oliveira

doi:10.3897/zookeys.482.6909

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: Pseudancistrus kayabi from the rio Teles Pires (rio Tapajós basin) and Pseudancistrus asurini from the rio Xingu. The new species are distinguished from congeners (Pseudancistrus barbatus, Pseudancistrus corantijniensis, Pseudancistrus depressus, Pseudancistrus nigrescens, Pseudancistrus reus, and Pseudancistrus zawadzkii) by the coloration pattern. Pseudancistrus kayabi has dark bars on the dorsal and caudal fins which are similar to that of Pseudancistrus reus from the Caroní River, Venezuela. Pseudancistrus asurini is unique among Pseudancistrus in having whitish tips of the dorsal and caudal fins in juveniles to medium-sized adults.

Highlights

With 892 species, the suckermouth armoured catfish family Loricariidae is the fifth most species-rich family of vertebrates and one of the most species-rich groups among Neotropical fishes (Eschmeyer and Fong 2014)
Morphometrics are given as percentages of standard length (SL), except for subunits of the head region that are expressed as percentages of head length (HL)
The two new species, P. kayabi and P. asurini, are typical Pseudancistrus, recognized by non-evertible cheek plates and the presence of hypertrophied odontodes along the snout margin. This last character is shared with species of Lithoxancistrus and Pseudolithoxus

Summary

Introduction

With 892 species, the suckermouth armoured catfish family Loricariidae is the fifth most species-rich family of vertebrates and one of the most species-rich groups among Neotropical fishes (Eschmeyer and Fong 2014). The loricariids are distinguished by having a ventral oral disk, the body covered with ossified dermal plates, and the presence of small external teeth known as odontodes. Within this family, all species that have highly evertible clusters of cheek odontodes are placed within the subfamily. C. Silva et al / ZooKeys 482: 21–34 (2015)

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