A new species of Hemibrycon (Teleostei: Characiformes: Characidae) from the río Ucayali drainage, Sierra del Divisor, Peru

Vinicius A Bertaco,Luiz R Malabarba,Max Hidalgo,Hernán Ortega

doi:10.1590/s1679-62252007000300003

Abstract

A new characid species, Hemibrycon divisorensis, is described from the río Ucayali drainage, Loreto, Peru. The new species is distinguished from all Hemibrycon species by the presence of a wide black asymmetrical spot covering base of caudal-fin rays and extending along entire length of caudal-fin rays 9 to 12-13 (except from H. surinamensis), and a black band in the lower half of the caudal peduncle extending from the region above the last anal-fin rays to the caudal-fin base. Furthermore, it is distinguished from most species of the genus by the number of scale rows below the lateral line (4-5 vs 5-9), except H. jabonero, H. microformaa, H. orcesi, and H. surinamensis. It differs from these species by scale and fin ray counts and color pattern. The lack of a supraorbital in Hemibrycon species is discussed and confirmed.

Highlights

Hemibrycon is a Neotropical genus of characid fishes which comprises about 21 valid species, occurring in the coastal drainages of the Caribbean sea and East Pacific in Colombia, río Tuira drainage in Panama, rivers drainages in Trinidad and Tobago, río Orinoco and lago Maracaibo in Venezuela, upper río Amazonas in Bolivia, Peru, and Ecuador, and coastal drainages of French Guiana and Suriname (Lima et al, 2003; Román-Valencia & Ruiz-C., 2007).The genus Hemibrycon was proposed by Günther (1864), as a subgenus of Tetragonopterus Cuvier, differing by “cleft of the mouth of moderate width, and the entire edge of the maxillary denticulated”
Malabarba & Weitzman (2003) recognized Hemibrycon as belonging to a large monophyletic clade inside Characidae, based on the putative derived presence of four teeth in the inner series of the premaxilla and reduced number of dorsal-fin rays (ii,8). They considered Hemibrycon and Boehlkea as apparently the most basal genera in that clade, by lacking all specializations related to insemination, development of caudal- and/or anal-fin glands or the jaw and teeth modifications related to the ventral position of the mouth, as observed in the remaining genera and species of Clade A
The new species is described in Hemibrycon considering the definition of the genus currently in use, proposed by Günther (1864) and further elaborated by Eigenmann (1927)

Summary

Introduction

Hemibrycon is a Neotropical genus of characid fishes which comprises about 21 valid species, occurring in the coastal drainages of the Caribbean sea and East Pacific in Colombia, río Tuira drainage in Panama, rivers drainages in Trinidad and Tobago, río Orinoco and lago Maracaibo in Venezuela, upper río Amazonas in Bolivia, Peru, and Ecuador, and coastal drainages of French Guiana and Suriname (Lima et al, 2003; Román-Valencia & Ruiz-C., 2007). Malabarba & Weitzman (2003) recognized Hemibrycon as belonging to a large monophyletic clade inside Characidae (therein named Clade A), based on the putative derived presence of four teeth in the inner series of the premaxilla and reduced number of dorsal-fin rays (ii,). Malabarba & Weitzman (2003) recognized Hemibrycon as belonging to a large monophyletic clade inside Characidae (therein named Clade A), based on the putative derived presence of four teeth in the inner series of the premaxilla and reduced number of dorsal-fin rays (ii,8) They considered Hemibrycon and Boehlkea as apparently the most basal genera in that clade, by lacking all specializations related to insemination, development of caudal- and/or anal-fin glands or the jaw and teeth modifications related to the ventral position of the mouth, as observed in the remaining genera and species of Clade A. This is part of a systematic study of Hemibrycon conducted by the senior author (doctoral thesis)

Materials and Methods

Discussion

Literature Cited