An updated list of the ichthyofauna of Ipanema National Forest, São Paulo, Brazil

The Ipanema National Forest has been thoroughly studied in the last 25 years, and 50 species of fish species (47 native and three invasive) were reported in 2013. Intensive inventory work carried out by us between 2012 and 2017 found 39 additional species distributed in five orders and 13 families. Our study provides new data which may help efforts to preserve the Ipanema National Forest.


Introduction
Conservation units are important in preservation (Dala-Corte et al. 2009), protecting and delimiting high biodiversity areas that require protection. The reduction of natural habitats by anthropization is one of the main reasons of biodiversity loss, including freshwater fish diversity (Cetra et al. 2010), but conservation units have a central role in providing shelter and on keeping habitat diversity, critical aspects in the survival of species. In Ipanema National Forest, a national conservation unit created in 1992 (Smith and Regalado 2008), various lentic and lotic environments can be found that provide conditions for the maintenance of the ichthyofauna. Although protected areas serve to preserve biodiversity by the preservation of habitats, there is still a lack of information about this conservation area, especially regarding aquatic ecosystems (Casarim et al. 2020). Smith et al. (2013) provided a preliminary checklist of fish species of Ipanema National Forest based on previous reports by Smith (1999), Smith and Marciano (2000) in particular, as well as studies that were part of the Ipanema National Forest Management Plan in 2003(Brazil, 2003 and the studies of Smith (2003), Smith et al. (2007), Smith and Regalado (2008), and Smith et al. (2009). These sources list a total of 50 species distributed in seven orders, 21 families, and 41 genera of fishes living on Ferro Stream and Verde River, in one stretch of the Ipanema River (dam and downstream the dam), in the Hedberg Reservoir, in the Limão and Cobra lagoons and in other lagoons that occur in the conservation unit. The goal of our study was to add to the extensive information on the ichthyofauna of Ipanema National Fore by sampling new locations and recording additional species with experimental fishing techniques and by consulting more recent publications.

Study Site
Ipanema National Forest has an area of 5,180 ha (approximately 23°25′S, 047°37′W at its center). It encompasses the municipalities of Iperó, Araçoiaba da Serra, and Capela do Alto in southeastern São Paulo state, 125 km far from the capital, São Paulo ( Fig. 1).

Methods
Samples were collected from 2012 to 2017 in various water bodies using active capture methods: cast nets, trawl nets, hand nets, and a fishing rod with hooks ( Table  1). The collections were made under permit from Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio 43596-1). The specimens captured were euthanized in eugenol, fixed in 10% formalin, and preserved in 70% alcohol. Species were identified using available literature, keys, and the help of specialists. Voucher specimens were deposited at the Ichthyology Collection of the Fish Department of the Museu de Zoologia da Universidade de São Paulo (MZUSP) (Appendix) and the Laboratory of Structural and Functional Ecology of Ecosystems of the Universidade Paulista, Sorocaba Campus (LEEF). An extensive bibliographical review was carried out to verify the publication of ichthyological data in Ipanema National Forest since 2013.

Results
In this study, we added 39 species in addition to those already recorded in previous studies, resulting in a total of 89 species for Ipanema National Forest. The 39 species recorded here for the first time are distributed in five orders and 13 families. The taxonomic list of identified species is shown in Table 2, and the newly recorded species are shown in Figure 2. Most of these species belong to the orders Characiformes (23 species) and Siluriformes (10 species). The most diverse families were the Characidae and Loricariidae with 13 and six species, respectively.

Order Characiformes Family Acestrorhynchidae
Acestrorhynchus lacustris (Lütken, 1875) Figure   Identification. Body deep and high; mouth terminal; inner row of premaxilla with 5 teeth, outer row with 4 or 5, dentary with 8-16, no maxillary teeth. Lateral line complete, with 34-36 scales; transversal series above lateral line with 7-7½ scale rows and below with 6-6½ scale rows. Dorsal fin with 10 rays, pectoral fin with 12 or 13 rays, pelvic fin with 9 rays, anal fin with 25-27 rays, and caudal fin with 19 rays. Ground color silvery; one black rounded humeral blotch followed by another vertically elongated humeral blotch to median caudal-fin rays. Yellowish fins (Graça and Pavanelli 2007;Ota et al. 2018). Identification. Body high and laterally compressed; premaxilla with two rows of teeth; outer row with three to six teeth; cycloid scales regularly imbricated; lateral line slightly curved; greatest body depth anterior to dorsal fin origin (Tatsumi 2006).

Discussion
The predominance of the orders Characiformes, Siluriformes, Gymnotiformes, and Cichliformes was expected as they have greatest number of species in the Neotropical Region (Lowe-McConell 1987;Castro and Menezes 1998;Reis et al. 2003;Winemiller et al. 2008). Most of the species in Ipanema National Forest are native, small, and dependent on sources of allochthonous material from riparian vegetation, or they are endemic to the Alto Paraná and the Sorocaba and Middle Tietê river basins (Smith et al. 2013). Although only three species are Endangered, the presence of a diverse fish fauna in the Ipanema National Forest is indicative of the importance of this conservation unit. Ipanema National Forest is one of the most important sites for the conservation of the fish fauna of the Sorocaba river basin. Prochilodus vimboides, Pseudopimelodus mangurus (Valenciennes, 1835), and Bunocephalus larai (Ihering, 1930) have been assessed as Vulnerable in the state of São Paulo (Oyakawa et al. 2010). Two rare species, Tatia neivai (Ihering, 1930) and Bunocephalus larai, have already been recorded in the Ipanema River.
The species P. vimboides was not captured during this work. Currently, in addition to being rare in the literature, the catch records of P. vimboides are also scarce (Vieira and Rodrigues 2010;Marques et al. 2013). According to Polaz et al. (2011), there was a large catch of approximately 15 tons of curimbatás, in 1952 in the Paraíba valley region (mainly in the Paraíba do Sul River); the species was probably P. vimboides. Honji et al. (2017) mentioned that P. vimboides is present in the Estação de Hidrobiologia e Aquicultura de Paraibuna of CESP and Piabanha Project (NGO Piabanha Project), two conservation units in a tributary of the Paraíba do Sul River.
We noticed that P. vimboides is replaced by its congener, Prochilodus lineatus. Possibly, the process of substituting one species for another is due to its lower biotic potential and may also be associated with environmental changes. This explains the increasingly rare records of P. vimboides and the more abundant P. lineatus (Polaz et al. 2011). Honji et al. (2017 highlighted two threats to P. vimboides. Most severe is the construction of dams and reservoirs. As a rheophilic species, the genus Prochilodus needs to migrate to reproduce, and with the rivers blocked, it is not possible to complete the migration process. The second threat is the presence of introduced species, which is currently one of the largest threats to global biodiversity (Moraes et al. 2017).
The presence of Psalidodon paranae (previously identified as Astyanax scabripinnis), a species typically found in streams (Castro and Casatti 1997) was found in the Ribeirão do Ferro. This species is widely distributed in headwaters, indicating its preference for small streams. According Oyakawa et al. (2006), knowledge on the species diversity in headwaters is lacking and headwater fish species are in general small and uninteresting for fishing, habitats are cryptic, and aquatic environments are quite restricted. Oyakawa et al. also highlight the difficulty in sampling all species at the headwaters of rivers.
Among all the species found, only Phalloceros harpagos Lucinda, 2008 was found in all collecting sites, which can be attributed to this species′ successful adaptation to the different habitat types in quieter waters (Mazzoni et al. 2011). The predominant species at our sampling sites are native and non-threatened species, as is expected for Neotropical hydrographic basins and in São Paulo state. These small, Neotropical species depend on the marginal vegetation (Oyakawa and Menezes 2011).