Headwater stream fish fauna from the Upper Paranapanema River basin

The Paraná River basin has about 600 fish species. In the Upper Paraná, 310 fish species were recorded, with 52 species were registered in the streams and headwaters of the Paranapanema River. The aim of this study was to characterize the stream fish communities in the Upper Paranapanema River basin. Samplings were conducted with electrofishing during the dry season in the year of 2014. The collection effort consisted of 30 streams stretches. As a result, 41 species of stream fish were recorded in the Upper Paranapanema River basin, distributed in 26 genera, 11 families and 7 orders. Thirty-nine percent of the species can be considered rare, 41% intermediate and 20% common. We captured approximately eight species by stream stretch and the estimated richness (Schao2) was 40 ± 6 species. Around 40% of the individuals had less than 50 mm in length.


Introduction
The Paraná River basin is the second largest in area in the Neotropical region (Agostinho & Júlio Jr. 1999), with about 2.6 million km 2 .Older estimates suggest that this basin has nearly 600 fish species (Bonetto 1986).Recently, 310 fish species were recorded in the Upper Paraná (Langeani et al. 2007), which comprises approximately 900,000 km 2 and the portion of this basin in São Paulo State includes 260 species along the Paraná River and its main tributaries, Paranapanema, Tietê and Grande (Oyakawa & Menezes 2011).About 65% of these species were small sized (less than 21 cm), and occurred in streams and headwaters (Langeani et al. 2007).Recent inventories documented a high diversity fish fauna for the Upper Paraná (Casatti et al. 2001, Castro & Casatti 1997, Castro et al. 2003, 2004, 2005, Langeani et al. 2005ab, Fagundes et al. 2015).
As recommended by Casatti et al. (2008), this study intended to perform the following actions: (i) survey the fish populations in the Upper Paranapanema River basin, which currently presents a knowledge gap; (ii) study the fish community from streams and headwaters that are especially interesting for sharing species with neighboring basins; (iii) provide information on the fish populations that can be used in the monitoring of riparian forests restoration projects.This study aimed to characterize the stream fish communities in the Upper Paranapanema River and supplement the species lists of Castro et al. (2003).

Study area
The Upper Paranapanema River basin is located in the Unidade de Gerenciamento dos Recursos Hídricos [Water Resources Management Unit] (UGRHI 14).This unit presents agriculture activity and population density around 30 inhabitants/km 2 .About 15% of the area is covered by native vegetation, and the headwaters are covered by reforested area (Eucaliptus spp.) and native forests (CETEC 1999).The headwater streams are in the Serra de Paranapiacaba, at about 1100 m altitude, and are tributaries of the Paranapanema River, which, after running along 500 km, will flow into the Paraná River.

Fish Sampling
Fish sampling was conducted from June to November 2014 as the associations between fish assemblage and environmental structure are better described in the dry season (Pinto et al. 2006).Furthermore, it is important to control the effect of sources of temporal variation.
The wadeable stream stretches have at least one sequence of rifflerun-pool meso-habitats.The organisms collected were fixed for 48h in 4% formalin and then transferred to 70% alcohol.Vouchers of the species collected were deposited in the collection of Laboratório de Ictiologia of the Departamento de Zoologia e Botânica da UNESP -São José do Rio Preto ) and of Laboratório de Ictiologia de Ribeirão Preto -FFCLRP/USP (LIRP 11826).The specimens were identified according to Castro et al. (2003), Castro & Vari (2004), Vari & Castro (2007), Lucinda (2008), Zawadzki et al. (2008), Lippert et al. (2014) and with the assistance of specialists in some groups.

Results and Discussion
We captured about 7 kg of fish: 1878 individuals, 41 species, 26 genera, 11 families and 7 orders (Table 2).Following the criteria of Teshima et al. (2015), 16 species (39%) can be considered rare, 17 species (41%) are intermediate and 7 species (20%) are common.On average, we captured approximately 8 species by stream stretch and the estimated richness (Schao2) was 40 ± 6 species.Around 40% of individuals had less than 50 mm in length.
The orders Siluriformes and Characiformes represented the majority of the species richness, 44% and 37% respectively, reflecting a well-known pattern recognized for South American rivers (Lowe-McConnell 1999).Twelve species are not on the list of species that occur in the Upper Paraná (Langeani et al. 2007), and 18 are not in the list by Castro et al. (2003) that collected fish in streams of the Paranapanema basin.
Some species have been listed with different names as presented in Castro et al. (2003) and Langeani et al. (2007) (Table 2, with asterisk).This happened because some species that had been recognized as distinct morphotypes were later formally described.This is the case of Astyanax sp1 and Astyanax sp2 (Castro et al. 2003), later described as A. bockmanni and A. biotae (Castro & Vari 2004, Vari & Castro 2007).A Bryconamericus morphotype with humeral spot was identified only at the genus level (Castro et al. 2003).Langeani et al. (2007) identified a morphotype of Bryconamericus with humeral spot as B. iheringii, highlightening that this could probably represent a new species.Also, these previous lists included Phalloceros caudimaculatus as a single species, but we found herein both species currently recognized in the genus for the Paranapanema basin (see below).
The São Paulo State fish fauna is relatively well known (Langeani et al. 2007, Oyakawa & Menezes 2011).However, there are still many taxa to be better studied and that probably represent new species.It is known, for instance, that Astyanax scabripinnis represents a group of species, some of which still undescribed, and further detailed analysis based on larger and more complete sample series may result in the description new species (e.g., Moreira-Filho & Bertollo 1991, Bertaco & Malabarba 2001, Bertaco & Lucena 2006, Fagundes et al. 2015).
Neoplecostomus selenae, Phalloceros reisi and P. harpagos were described in 2008 but were already cited as new species under description by Langeani et al. (2007).Otothyropsis biamnicus was recently described (Calegari et al. 2013) and included in a recent species list of the Upper Paraná (Fagundes et al. 2015).The species mentioned above were described in the last 10 years, hence discovered in relative recent times.In addition, some taxa could not be identified to species level, probably because they represent new taxa awaiting description.As noted by Langeani et al. (2007), this may be the case of Hypostomus sp1, Hypostomus sp2, Trichomycterus sp1, Trichomycterus sp2 and Othothyropsis sp, which should contribute to the increase in the species richness from the Upper Paraná.
The exotic species Misgurnus anguillicaudatus had been registered in the Iguaçu River basin (Ingenito et al. 2004, Vitule 2009) and was recently captured in preserved streams in the Ribeira de Iguape River basin (Gomes et al. 2011, Cetra et al. 2012).We herein present the first record of this species in the Paranapanema River basin in the São Paulo State.
Among the 41 fish species sampled in the present study, we highlight Neoplecostomus selenae, a species listed as vulnerable on the list of endangered species in São Paulo State (Oyakawa et al. 2009).This species was included in that list because it was known solely from the type locality in Ribeirão das Bateias basin, Ribeirão Grande municipality (Zawadzki et al 2008).For the conservation of this species, Oyakawa et al. (2009) suggested habitat protection and scientific research to obtain data on its biology, and inventories to better access the distribution of this species.The results in the present study expanded the area of occurrence of N. selenae (Apiaí-Guaçu, Apiaí-Mirim, Guapiara, Itararé, Panema, Taquaral, Taquari-Guaçu and Verde sub-basins) yielding new specimens for further studies.
The present study complemented data on fish populations of the Upper Paraná River basin, specifically of the tributary streams of the Paranapanema River (e.g., Castro et al. 2003, Langeani et al. 2007), representing a considerable increase in the richness in the latter drainage, in addition to a few putative new species.Although the fish fauna of the Paraná River basin is relativelky well known (eg, Langeani et al. 2007, Oyakawa

Table 2 .
Langeani et al. (2007) headwater streams from Upper Paranapanema River basin with respective status.X: species listed inCastro et al. (2003)and/orLangeani et al. (2007).Asterisk indicates species listed with a different name in previous papers.