Guillermo Enrique Terán

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

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.

Living in the waterfalls: A new species of Trichomycterus (Siluriformes: Trichomycteridae) from Tabay stream, Misiones, Argentina

A new species assigned to the genus Trichomycterus from the area of the waterfalls of Tabay stream, Paraná River basin, Misiones, Argentina, is described. Trichomycterus ytororo sp. nov. is distinguished from all other species in the genus by the presence of 31–35 dorsal procurrent caudal-fin rays and the combination of some external characters such as: coloration, number of pectoral–fin rays and pores of the laterosensory canals. The new taxon belongs to a presumably monophyletic group of species composed of T. crassicaudatus, T. igobi, and T. stawiarski based on the presence of 24 or more thickly ossified and rigid procurrent caudal-fin rays with a slender distal tip extending along the tips of at least ten neural spines.

Geographical distribution of Austrolebias monstrosus (Huber, 1995), A. elongatus (Steindachner, 1881) and A. vandenbergi (Huber, 1995) (Teleostei: Cyprinodontiformes), with comments on the biogeography and ecology of Rivulidae in Pampasic and Chaco floodplains

We present a new record for Austrolebias elongatus from Gualeguaychu, in Entre Rios province, Argentina, based on new fieldwork and a revision of material deposited in national ichthyological collections. We also give evidence on the erroneous records of Austrolebias monstrosus and A. vandenbergi from Ituzaingo, Corrientes province, as well as present additional records from Salta province for those species. Material previously determined as A. elongatus from Santiago del Estero is attributed to A. monstrosus . We restrict the distribution of these two species to Semi-arid Chaco Region in Argentina, Paraguay and Bolivia.

First record of Astyanax puka Mirande, Aguilera & Azpelicueta, 2007 (Teleostei: Characidae) in Juramento River basin, Salta, Argentina

Astyanax puka was described from the endorheic Rio Sali basin, Argentina, and it was not previously recorded elsewhere, being considered until now as endemic from that basin. Herein we record for the first time this species in the Rio Juramento basin, Rio de La Plata system.

A new species of Astyanax (Ostariophysi: Characidae) from the headwaters of the arheic Río Sucuma, Catamarca, Northwestern Argentina

is described from the arheic system of Rio Sucuma, in Catamarca, Northwestern Argentina. The new species is distinguished from its congeners by a combination of characters including the presence of a broad vertical humeral spot, absence of maxillary teeth, and absence of in posterior field of scales. Furthermore, this species is

First record of Hypostomus boulengeri (Siluriformes: 1 Loricariidae) from Río Bermejo basin.

Hypostomus boulengeri (Eigenmann y Kennedy 1903) es una especie poco conocida registrada de las cuencas de los Rios Paraguay Parana. En este trabajo reportamos por primera vez la presencia de esta especie en la cuenca del Rio Bermejo representado una ampliacion en la distribucion de mas de 600km.

Occurrence of Astyanax dissensus Lucena & Thofehrn, 2013 (Teleostei: Characidae) in Argentina

The occurrence of Astyanax dissensus in the Uruguay River, at Yapeyu, Corrientes, Argentina is reported for the first time in the country.

First record of the banjo catfish Bunocephalus doriae Boulenger 1902 (Siluriformes: Aspredinidae) in the Bermejo River basin, Salta, Argentina

Intense sampling in the upper Bermejo River basin revealed the presence of specimens of the aspredinid genus Bunocephalus . After detailed morphological and morphometric analyses specimens were identified as Bunocephalus doriae . This is the first record of any member of the Aspredinidae in the upper Bermejo River basin.

Range extension of Hypostomus cochliodon Kner, 1854 (Siluriformes: Loricariidae) in Bermejo River, Salta, Argentina

Hypostomus cochliodon Kner, 1854 had been recorded from Paraguay and Parana rivers in Argentina. We recorded for the first time specimens of H. cochliodon to the Bermejo River basin. It is also the first record of this species to Salta province, Argentina.