Expanding the geographical distribution of Astyanax biotae Castro & Vari , 2004 ( Characiformes , Characidae ) , with comments on its conservation status

Astyanax biotae Castro & Vari, 2004 was only known from the type locality, a first-order stream from the lower Paranapanema River, a left bank tributary from the upper Paraná river basin. We report A. biotae from the Ivinhema River, rio do Peixe and other tributaries of Paranapanema River, expanding its distribution to both margins of the Paraná River. Astyanax biotae is zooplanktivorous and regarding its conservation status, can be classified as Least Concern.

Among the hundreds of fish species that inhabit the upper Paraná River, there are 7 species of Astyanax Baird & Girard, 1854 (Lima et al. 2003, Graça and Pavanelli 2007, Langeani et al. 2007, Vari and Castro 2007, Garutti and Langeani 2009, Lucena and Soares 2016).Astyanax is one of the most diverse genera in the Characidae (Schmitter-Soto 2017).The genus is widely distributed in the Neotropics (Casciotta et al. 2005) and does not form a monophyletic clade (Mirande 2010, Rossini et al. 2016).The most encompassing taxonomic revision of Astyanax was made by Eigenmann (1910Eigenmann ( , 1917Eigenmann ( , 1921Eigenmann ( , 1927) ) who proposed the current definition of the genus.Following Eigenmann (1921), the genus is diagnosed by a combination of characters: 2 rows of premaxillary teeth, 5 teeth in the inner premaxillary series, lateral line complete, adipose fin present and caudal fin naked.
Astyanax biotae Castro & Vari, 2004 (Fig. 1) was described from a single locality, a first-order stream situated about 2.5 km from the mouth of the Paranapanema River, left bank of upper Paraná River.Thirteen years after its description, A. biotae is still only known from its type locality.The examination of Astyanax samples deposited at the DZSJRP (Departamento de Zoologia e

Methods
Counts and measurements were taken following Fink and Weitzman (1974) and Menezes and Weitzman (1990), except for number of scales series below the lateral line, which follows Bertaco and Lucena (2006).Additional measurements include: (1) the distance from pectoral-to pelvic-fin origins; (2) the distance from pelvic-to anal-fin origins.Measurements were taken point-to-point using a digital caliper to the nearest 0.1 mm, on the left side of the fish.All measurements are expressed as percentages of SL, except those subunits of the head, which are expressed as percentages of head length (HL).In Table 1, proportions were rounded to 0.1%.

Discussion
The discovery of A. biotae in 2004 was a result of the extensive fauna study implemented by the Program BIOTA/FAPESP through the thematic project "Fish diversity of the headwaters and streams of the upper Paraná river system in the state of São Paulo, Brazil".Castro and Vari (2004) described A. biotae solely based on material from the lower Paranapanema River, its type locality.The type locality of A. biotae is a first order creek surrounded by a narrow area of native vegetation.For that reason, Castro and Vari (2004) suggested that the species may be at risk of extinction since the area was threatened by several anthropogenic activities (e.g.deforestation, extensive use of fertilizers and pesticides in agricultural practices).Here we report that A. biotae also occurs in São Paulo state (rio do Peixe basin, and tributaries of lower Paranapanema River and Paraná River, all left bank of upper Paraná River) and Mato Grosso do Sul state (Ivinhema River basin, right bank of upper Paraná River) (Fig. 2).
Even though the known geographic distribution of A. biotae is still restricted to a relatively small area in the upper Paraná drainage and most sites are threatened by anthropogenic activities, no threats were detected in rio Ivinhema at Parque Estadual das Várzeas do Rio Ivinhema (PEVRI) (Fig. 3).Therefore, A. biotae can be classified as Least Concern, according to the International Union for Conservation of Nature criteria (IUCN 2017).
The feeding habits for the specimens from rio Ivinhema were also determined.Astyanax biotae can be considered zooplanktivorous, as more than 80% of its diet was composed by microcrustaceans, mainly Copepoda.The other items consumed were chironomid larvae, ephemeropteran naiads, and fruits.

Figure 2 .
Figure 2. Map of Central Brazil showing the records of Astyanax biotae.Red star indicates the type locality and yellow dots new records for the species.