Ichthyofauna of streams of the Rio Sapucaí basin , upper Rio Paraná system , Minas Gerais , Brazil

The Rio Sapucaí basin, in Minas Gerais State, Brazil, is one of the many watersheds of the upper Rio Paraná system. Ichthyofauna surveys in this basin, in general, are scarce. In addition, small rivers and streams of the region have been targets of anthropogenic actions (e.g., pollution) – which suggest that more ichthyological studies must be performed within the watershed. In this study we provide a survey of species that occur within three streams of the lower Rio Sapucaí basin. Samples were collected in April, July, and November 2017 and in May 2018. Collections resulted in 349 individuals belonging to 28 species, five orders, and 12 families. Among our findings are three putatively undescribed species and the first record of Oligosarcus argenteus and Pareiorhina hyptiorhachis within the Rio Paraná system.


Introduction
Ichthyofauna surveys are important for the conservation of freshwater fishes at both short and long-term scales.These studies provide additional information about species' distribution (e.g., Valdiviezo-Rivera et al. 2017, Bertora et al. 2018, Delariva et al. 2018, Honorio & Martins 2018, Oliveira-Silva et al. 2018) -which, in turn, may assist in new assessments about their "conservation status" (e.g., Melo et al. 2017).Additionally, surveys provide useful data for the establishment of freshwater protected areas (sensu Azevedo-Santos et al. 2018a).Therefore, ichthyological surveys should be carried out more frequently, especially in Brazilian freshwaters.
The Rio Sapucaí basin (~ 560,000 hectare; Magalhães Jr & Diniz 1997), Minas Gerais, Brazil, is part of the upper Rio Paraná system (Magalhães Jr & Diniz 1997).To our knowledge, only two ichthyological surveys have been published for this watershed.Ingenito & Buckup (2007) provided a list with the fishes of three localities in the upper portion of the basin near the Serra da Mantiqueira.Subsequently, Belei & Sampaio (2012) publishes a work with the fishes from the Rio Lourenço Velho, a direct tributary of the Rio Sapucaí.However, streams of the lower region of the watershed remain understudied.
Countless rivers and streams of the Rio Sapucaí basin have been targets of anthropogenic actions (e.g.small dams; see Belei & Sampaio 2012), which can significantly impact the overall biodiversity (Pelicice et al. 2017).These actions coupled with the lack of biodiversity knowledge suggest that more surveys must be conducted within the watershed.In this study we provide the results of a fish survey conducted in three different streams of the lower portion of the Rio Sapucaí basin, in Minas Gerais, Brazil.

Material and Methods
Fishes were collected in April, July, and November 2017, and in May 2018 (totaling four collections, one per month), across three different streams of the Rio Sapucaí basin (Table 1; Figure 1-2).Sampling occurred during daytime roughly 100 to 200 meters upstream of each stream.Collections were carried out with a small cast net (1.4 cm of mesh in opposite nodes), a hand net (~1.5 mm mesh), gill nets (1 and 2 cm in opposite nodes), and fishhooks of different sizes.Collections were performed with permission issued by Brazilian Institute of Environment and Renewable Natural Resources (IBAMA, in Portuguese) -license numbers 46904-1 and 63177-1.
Species reported in Table 2 were classified according to Fricke et al. (2018).

Results
A total of 349 individuals representing five orders, 12 families, and 28 fish species (Table 2) were collected from all reaches (i.e., R1, R2, R3).The order and family with highest species richness, considering all reaches, was Siluriformes and Characidae, respectively (Figure 3-4).We found the highest species richness at R3, with a total of 23 species, followed by R1 with nine and R2 with seven (Table 3).
Three putatively undescribed species were also collected: Astyanax sp. and 'Heptapterus' sp., both from R1, and Imparfinis sp., from R3.Additionally, we found individuals of Oligosarcus argenteus and Pareiorhina hyptiorhachis, which represent the first record of these two species within the Rio Paraná system (Table 3).Individuals of Trichomycterus septemradiatus were collected at R1, which also  expands the distribution of this species into the Rio Paraná system.Lastly, we recorded Knodus moenkhausii and Poecilia vivipara, two non-native fish species within the Rio Sapucaí basin.

Discussion
Overall, members of the orders Siluriformes and Characiformes comprise the majority of species found in the three sampled streams of the Rio Sapucaí basin (see Figure 3).Dozens of investigators who have conducted fish surveys of rivers, reservoirs, or streams of the upper Paraná basin (e.g., Casatti et al. 2003, Smith et al. 2007, Smith & Petrere Jr 2007, Fagundes et al. 2015, Frota et al. 2016, Santos et al. 2017, Cavalli et al. 2018) have also found species richness to be highest in these orders.Therefore, the relatively high species counts in these two orders, as we found in this study, is an expected result for many regions of the upper Rio Paraná system.
The families with highest species richness in the lower Rio Sapucaí region are Characidae and Heptapteridae.However, in context of the Rio Paraná basin as a whole, Loricariidae has been reported to contribute higher species richness than Heptapteridae (Langeani et al. 2007).This suggests that loricariid species may have been undersampled in this survey.Specimens were collected only during the day (see Material and Methods section), which may have contributed to an undersampling of loricariids and possibly other groups (see below).Therefore, for future studies we recommend sampling at each stream during the night as well.
Three putatively undescribed species (i.e., Astyanax sp., 'Heptapterus' sp., and Imparfinis sp.) were collected during this survey (Figure 5a, b, c).In addition to this study, Ingenito & Buckup (2007) discovered six undescribed species within the upper Rio Sapucaí basin.With these results we believe more ichthyological surveys in rivers and streams of the Rio Sapucaí basin are necessary, as additional undescribed species likely remain to be discovered.Langeani et al. (2007) did not report Oligosarcus argenteus (Figure 5e) within the upper Rio Paraná system.Additionally, in a recent revision of the genus Oligosarcus, Ribeiro & Menezes (2015) reported this species as endemic to the Rio São Francisco and Rio Doce basins.In turn, Pareiorhina hyptiorhachis (Figure 5f) was recently described from the Rio Paraíba do Sul basin (Silva et al. 2013).Our study reports individuals of O. argenteus at R1 and individuals of P. hyptiorhachis at R1 and R2.Therefore, these findings represent the first records of these two species in the Rio Sapucaí basin, as well as in the Rio Paraná system in general.Trichomycterus septemradiatus (Figure 5h) was previously known only from its type locality, a single stream in the Rio Sapucaí basin (Katz et al. 2013).Our study reports individuals of T. septemradiatus at R1; therefore, we extend the distribution of this species within the basin.
Individuals of two non-native species, Knodus moenkhausii and Poecilia vivipara, were collected in this survey (see Table 3).Knodus moenkhausii (Figure 5d) has previously been assigned by different authors as non-native to the upper Rio Paraná system (e.g., Langeani et al. 2007, Souza et al. 2015, Azevedo-Santos et al. 2018b).Poecilia vivipara (Figure 5g) has also been reported by Langeani et al. (2007) as a non-native species introduced to the upper Rio Paraná system.Therefore, we consider K. moenkhausii and P. vivipara as non-native species within the Rio Sapucaí basin (sensu Langeani et al. 2007).However, sources of these introductions remain unknown.
Here we contribute to the knowledge of the fish fauna of the Rio Sapucaí basin, upper Paraná system.However, we recognize this study likely represents a small fraction of what remains to be sampled within this basin.The presence of putative undescribed species coupled with increasing anthropogenic effects highlights the need to conduct more surveys of the ichthyofauna of waterbodies of this region.

Figure 1 .
Figure 1.Partial view of Rio Sapucaí (under influence of the Furnas reservoir), in Minas Gerais, Brazil, with the location of each reach (R1, R2, and R3) sampled.

Figure 4 .
Figure 4. Species richness by families collected in reaches of three different streams of the Rio Sapucaí basin, Minas Gerais, Brazil.

Table 1 .
Localities sampled from the lower Rio Sapucaí basin, Rio Paraná system, Minas Gerais, Brazil composed by sandy, with a local composed by rocks.Some locals impacted due the cattle breeding.

Table 2 .
Fish species captured in three reaches of streams of the Rio Sapucaí basin, upper Rio Paraná system, Minas Gerais, Brazil.