An endangered new species of seasonal killifish of the genus Austrolebias (Cyprinodontiformes: Aplocheiloidei) from the Bermejo river basin in the Western Chacoan Region.

Felipe Alonso,Yamila Cardoso,Ignacio García,Pablo Calviño,Guillermo Enrique Terán,Graciela García

doi:10.1371/journal.pone.0196261

Abstract

Austrolebias wichi, new species, is herein described from seasonal ponds of the Bermejo river basin in the Western Chacoan district in northwestern Argentina. This species was found in a single pond, a paleochannel of the Bermejo River, which is seriously disturbed by soybean plantations surrounding it. Despite intensive sampling in the area, this species was only registered in this pond where it was relatively scarce. Therefore, we consider this species as critically endangered. This species is the sister species of A. patriciae in our phylogenetic analyses and is similar, in a general external aspect, to A. varzeae and A. carvalhoi. It can be distinguished among the species of Austrolebias by its unique color pattern in males. Additionally, from A. varzeae by presenting a supraorbital band equal or longer than the infraorbital band (vs. shorter) and from A. patriciae by the convex dorsal profile of head (vs. concave). Further diagnostic characters and additional comments on its ecology and reproduction are provided.

Highlights

The genus Austrolebias Costa comprises 48 valid species [1, 2, 3] inhabiting seasonal ponds at the Southern portion of Neotropics in La Plata drainage, with one speciesfrom the Amazon basin in the Bolivian Chaco
The new species posses the diagnostic characters of the genus Austrolebias
Previous phylogenetic hypothesis of Austrolebias were very unstable in terms of presenting contradictory hypothesis of relationships among species and many unresolved clades or with low support [4, 23, 30], but still some group of species are recovered in the different analyses

Summary

Introduction

The genus Austrolebias Costa comprises 48 valid species [1, 2, 3] inhabiting seasonal ponds at the Southern portion of Neotropics in La Plata drainage, with one speciesfrom the Amazon basin in the Bolivian Chaco. Species of this genus are known from the lowlands in the ChacoPampasic floodplains of Argentina, Bolivia, and Paraguay. Six species of Austrolebias have been recorded from the Chaco Freshwater ecoregion sensu Hales and Petry [7]. We analyzed the phylogenetic relationship of this new taxon based on morphology and a molecular marker

Material and methods

Findings

Discussion