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.

basin.The specimens were collected near El Tunal dam, Metán department in Salta, Argentina.
Astyanax puka is distinguished from the remaining species of the genus by the presence of one distally expanded maxillary tooth with 7-9 cusps and combination of characters given by Mirande et al (2007).Specimens from Río Salí basin and the ones from Río Juramento basin are morphologically indistinguishable, and they belong to the same species.
The presence of Astyanax puka in the Río Juramento basin is not surprising since, according to López et al (2008), the Juramento and Salí-Dulce basins are included in the Ichthyological Pampean province due to the share of several fish species.The finding of Astyanax puka in the Río Juramento basin provides new evidence that reinforces the hypothesis of a close historical relationship of both basins.
The Río Juramento basin also shares elements with the Bermejo river basin, maybe because relatively malleable bedrock erosion, which potentially allows river captures on their heads.Therefore, although the populations are isolated at present, perhaps they had recent genetic exchanges (Mirande 2012).
Astyanax puka lives in sympatry in the Juramento River with other species of the genus: A. abramis, A. asuncionensis, A. eigenmanniorum, and A. lineatus.Also, Astyanax rutilus was found in the middle Juramento-Salado basin, Figueroa dam, Figueroa department in Santiago del Estero (see Appendix 1).
The fish genus Astyanax Baird & Girard (Characiformes: Characidae) is one of the dominant genera of South America freshwaters environments, including more than 140 nominal species (Eschmeyer and Fricke 2014).They present a wide distributional range, latitudinally from Patagonia in Argentina to New Mexico in the United States, and altitudinally from lowlands at sea level to mountain streams.Species of this genus are also found on both slopes of the Cordilleras from Ecuador to Mexico (Eigenmann 1917).This broad distribution is possible because this genus occupies a wide variety of environments in the Neotropical Region (Ringuelet 1975).
In recent years, several species similar to Astyanax eigenmanniorum (Cope 1894) in the number of anal-fin rays and scales of the lateral line have been described from Argentina, e.g., Astyanax Mirande et al. (2007) considered this species to be endemic of the Río Salí basin, with specimens in the Mandolo and Salí rivers in the province of Tucumán (Figure 1).
Río Juramento-Salado basin is an important fluvial system with about 1500 km from its origins - in the Calchaquies valley - to the Paraná River (Gonzo 2003).The study site corresponds to the upper portion of this basin.
A thorough revision of specimens of Astyanax from the Río Juramento basin, El Tunal, Salta, Argentina (Figure 1), revealed that A. puka (Figure 2) is also present in that First record of Astyanax puka Mirande, Aguilera & Azpelicueta, 2007 (Teleostei: Characidae)  Abstract: Astyanax puka was described from the endorheic Río Salí 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 Río Juramento basin, Río de La Plata system.

Figure 1 .
Figure 1.Map of Tucumán and Salta provinces, located at Northern Argentina.Salta province is colored in yellow.The square indicates the study site in the Río Juramento basin (25°13′ S, 64° 28′ W).Full red spots show sites where Astyanax puka was collected in Sali-Dulce basin (for detailed map see Mirande et al 2007) an empty red spot indicates the place where Astyanax puka was record in Juramento River.