Three new species of Astyanax from drainages of southern Brazil (Characiformes: Characidae)

Carlos A S De Lucena,Jonas Blanco Castro,Vinicius A Bertaco

doi:10.1590/s1679-62252013000300007

Abstract

Three new species of Astyanax are described from southern Brazil: A. dissensus and A. xiru from the laguna dos Patos system and rio Uruguay basin, the first species also occurring in the rio Tramandaí system, and A. procerus from the laguna dos Patos system. Astyanax procerus and A. xiru possess outer row premaxillary teeth pentacuspid and inner row heptacuspid, maxillary with one tri- to pentacuspid teeth, 18-23 branched anal-fin rays, and two humeral spots. Astyanax procerus has the largest body depth (38.3-46.0% of SL), while A. xiru has the lowest body depth (32.5-37.5% of SL) among the three species. The characters combination can distinguish these species from its congeners. Astyanax dissensus distinguish from Astyanax species by the presence of one developed heptacuspid teeth on maxillary, 22-28 branched anal-fin rays, 35-39 perforated scales along the lateral line, two humeral spots, conspicuous lateral band continuous on middle caudal rays, 6-7 scale row between dorsal-fin origin and lateral line, and head length 22.7-27.3% of SL. All three species has the predorsal region of the body scaled. An identification key to the species of Astyanax species from the rio Uruguay basin, and laguna dos Patos and rio Tramandaí systems is provided.

Highlights

The genus Astyanax Baird & Girard is a speciose group of characiform fishes, comprising 138 valid species (Eschmeyer, 2012), and occurring in all Neotropical drainages from the Colorado River, Texas and New Mexico, USA (OrnelasGarcia et al, 2008) to rio Colorado, northern of Patagonia, Argentina (Menni, 2004; López et al, 2008)
The three new species were assigned to Astyanax according to the traditional definition of the genus given by Eigenmann (1921, 1927)
None of the characters used by Eigenmann are unique to the genus along with the large number of species assigned to it, makes a difficult task to understand the boundaries of the genus

Summary

Introduction

The genus Astyanax Baird & Girard is a speciose group of characiform fishes, comprising 138 valid species (Eschmeyer, 2012), and occurring in all Neotropical drainages from the Colorado River, Texas and New Mexico, USA (OrnelasGarcia et al, 2008) to rio Colorado, northern of Patagonia, Argentina (Menni, 2004; López et al, 2008). With basis on the review study of Astyanax species from the rio Uruguay and laguna dos Patos system drainages, beyond of thirteen recognized species (A. aramburui Protogino, Miquelarena & López, 2006, A. brachypterygium Bertaco & Malabarba, 2001, A. cremnobates Bertaco & Malabarba, 2001, A. eigenmanniorum (Cope, 1894), Astyanax aff. With basis on the review study of Astyanax species from the rio Uruguay and laguna dos Patos system drainages, beyond of thirteen recognized species (A. aramburui Protogino, Miquelarena & López, 2006, A. brachypterygium Bertaco & Malabarba, 2001, A. cremnobates Bertaco & Malabarba, 2001, A. eigenmanniorum (Cope, 1894), Astyanax aff. fasciatus, sensu Melo & Buckup, 2006, A. henseli Melo & Buckup, 2006, A. jacuhiensis (Cope, 1894), A. laticeps (Cope, 1894), A. obscurus (Hensel, 1870), A. ojiara Azpelicueta & Garcia, 2000, A. paris Azpelicueta, Almirón & Casciotta, 2002, A. saguazu Casciotta, Almirón & Azpelicueta, 2003, and A. stenohalinus Messner, 1962), three new species were identified and here in described

Material and Methods

Results

Discussion

X X X distributions we can observe two distributional trends

Literature Cited