The Uberaba River is an important right-bank tributary to the Grande River, in the Upper Paraná River system, Brazil, and the main water source for the public supply of the Uberaba city, Minas Gerais state. An inventory, an identification key, and photographs of the fish species of the Uberaba River are provided, based on samples made between 2012 and 2014 at 14 sampling sites in the river system. A total of 73 species was recorded from six orders, 20 families, and 49 genera. Characiformes and Siluriformes are the most speciose orders and Characidae and Loricariidae are the most commonly recorded families. Most species are autochthonous, nine are considered allochthonous, and two species are exotic. The Uberaba River has a diverse and heterogeneous ichthyofauna, typical of rheophilic environments, with endemic species and few non-native species.

Brazilian Cerrado, freshwater fish, Neotropical Region, rheophilic environment, threatened species

Approximately 34,797 species of fish have been formally described worldwide (Fricke et al. 2018), and recent estimates suggest that ca. 13,000 species are partially or exclusively freshwater (Nelson 2016). The Neotropical region has a unique and diverse freshwater fish fauna (Albert and Reis 2011), with 9,100 species exclusively distributed in South America (Reis et al. 2016), an impressive number when compared to the global estimates. Approximately 43% of the Neotropical fish diversity occurs in Brazil (Buckup et al. 2007), and the Amazon and La Plata river drainages bear the largest fish diversity in South America (Langeani et al. 2007).

With geological origin dating from the Mesozoic (Neocretaceous), the La Plata River has an estimated drainage area of ca. 3 million km² across five countries, Bolivia, Brazil, Paraguay, Argentina, and Uruguay, and is the second largest drainage in South America, with the main drainages the Paraná-Paraguay drainage and Uruguay River (Albert and Reis 2011). The Upper Paraná River system is a catchment above the Sete Quedas Falls, currently flooded by the Itaipu hydroelectric dam, located at the border between Brazil, Paraguay, and Argentina. In the Brazilian portion, the Upper Paraná River system drains the states of Goiás, Minas Gerais, São Paulo, Mato Grosso do Sul, and Paraná, comprising the subsystems of the Grande, Paranaíba, Tietê, and Paranapanema rivers (Souza-Filho and Stevaux 1997; Langeani et al. 2007).

The Upper Paraná River, according to Langeani et al. (2007), harbors approximately 360 of fish species. Subsequently, Fagundes et al. (2015) provide 46 new records for this system. Additionally, at least 28 new species have been described since the last twenty years (e.g., Silveira et al. 2008; Martins and Langeani 2011a, 2011b; Carvalho and Langeani 2013; Serra and Langeani 2015). The increased number of species recorded in the Upper Paraná River in the last decade reflects intense sampling carried out in the region. Some authors (e.g., Langeani et al. 2007; Oyakawa and Menezes 2011) report that the Upper Paraná River is among the most well-sampled Brazilian regions, especially the São Paulo state (Oyakawa and Menezes 2011), and is one of the most impacted by dams, which considerably altered the hydrological regime and natural environments, affecting the dynamics and recruitment in fish populations (Agostinho et al. 2004). Fagundes et al. (2015) carried out intense samplings in tributaries of the Paranaíba, Araguari, and Grande rivers in the state of Minas Gerais, northwest, east, and southeast of the Triângulo Mineiro region, contributing significantly to the knowledge on local fish faunas. However, despite the recent contributions to the Upper Paraná River system, some areas were poorly sampled (e.g., south and southwest of the Triângulo Mineiro region, northeast and south parts of the Minas Gerais state, most of the Mato Grosso do Sul and Goiás states) and information on fish fauna composition and distribution is still missing.

The Uberaba River is a right-bank tributary of the Grande River, in the Upper Paraná River system, Brazil, and it is the main water source for Uberaba city in Minas Gerais state. In the driest period, the water level of the Uberaba River is very low and it is not able to be the only source of public water supply to the Uberaba city. This problem becomes worse with the intensive anthropogenic impact on the environment which results in modifications of hydrological dynamics and associated biotic structures (Candido et al. 2010; Cruz 2003; Valera et al. 2016). A dam located in the middle section of the Uberaba River, designed to capture and treat water for human consumption, significantly altered the natural characteristics and self-depuration capacity of the river (Sousa et al. 2016), even more aggravated by the high loads of raw sewage released into some river sections (Cruz 2003).

The fish fauna of the Uberaba River is only partially known, with only few sections sampled and no seasonal investigations (see SEMEA 2004; Souza et al. 2016). In this paper, we present an inventory of the fish fauna of the Uberaba River based on samples from several sections of the river system. In addition, an identification key and photographs of some species are presented.

In total, 2,722 specimens were collected and assigned to 49 genera and 73 species. The identified taxa are listed in Table 2. Most of the species in the Uberaba River are autochthonous (80.0%). Nine species (12.3%) have been recognized as allochthonous (Galeocharax gulo (Cope), Metynnis lippincottianus (Cope), Knodus aff. moenkhausii (Eigenmann & Kennedy), Hoplerythrinus unitaeniatus (Spix & Agassiz), Gymnotus inaequilabiatus (Valenciennes), Trichomycterus brasiliensis Lütken, Megalechis thoracata (Valenciennes), Poecilia reticulata Peters, and Cichla piquiti Kullander & Ferreira), and only two (2.7%) species are exotic (Coptodon rendalli (Boulenger) and Oreochromis niloticus (Linnaeus)). Six orders were recognized, of which Characiformes and Siluriformes were the most representative (90.3%), with eight families and 33 species for the former and five families and 27 species for the latter. Gymnotiformes (two families and three spp.), Cichliformes (one family and seven spp.), Cyprinodontiformes (two families and three spp.), and Synbranchiformes (one sp.) together represent 9.7% of the groups collected (Figure 3). Characidae (48.8%) and Loricariidae (16.8%) correspond to the most abundant families (Figure 4) and occur in the entire river system. The species richness suggested a longitudinal gradient, with more species in the lower reaches whereas in the upper reaches the richness does not exceed ten species (Figure 5 and Table 3). The loricariids are mainly represented by Hypostomus species, up to 92% of the total loricariid number. The most abundant species is Knodus aff. moenkhausii with 507 collected specimens comprising 38% of all characiform species. All other species have already been recorded in the Upper Paraná River.

Figure 3. 

Species richness for each fish order collected in Uberaba River, Upper Paraná River system, Brazil.

Figure 4. 

Species richness of each fish family collected in Uberaba River, Upper Paraná River system, Brazil.

Figure 5. 

Species richness along longitudinal gradient in Uberaba River, Upper Paraná River system, Brazil. Circle diameter corresponds to species richness.

The diversity recorded in the Uberaba River (73) is slightly greater than in similar tributaries of the Grande River in São Paulo state, in which 64 species have been recorded in the tributaries of the Pardo, Turvo, and Sapucaí rivers (Castro et al. 2004). Our data increase the number of species previously recorded for the Uberaba River by 44, which corresponds to an increase of 150% of the species referred so far in the region (see more details in SEMEA 2004; Souza et al. 2016). However, these figures may reflect the differences in sampling methods used by us and the previous authors as well as a larger area investigated in this study. Estimates of species richness and diversity considerably depend on methods used as discussed by Oliveira et al. (2014).

The number of species (73) recorded in the Uberaba River comprises ca. 19% of the total species number known in the Upper Paraná River system when compared to the data in Langeani et al. (2007). The ichthyofauna of the Uberaba River is composed mainly of autochthonous species, few allochthonous species and only two exotic species. The autochthonous origin of some of these species in the Upper Parana River still needs further research. For example, the scarcity of data on the origin or taxonomic status of some putative species such as Knodus aff. moenkhausii, Trichomycterus brasiliensis or Megalechis thoracata, does not allow to reasonably hypothesize on their origin.

Some species recorded in the Uberaba River potentially correspond to new species and some considerations are provided. Astyanax fasciatus (Cuvier) is described for the São Francisco River basin and it is widely distributed in the Paraná-Paraguay drainage and coastal drainages of eastern of Brazil. However, based on the definitions by Eigenmann (1921) it is possible to infer the existence of a "A. fasciatus species complex" in the Paraná-Paraguay and other coastal drainages. Thus, the name A. fasciatus should be used strictly for the São Francisco River lineage (Melo and Buckup 2006). In the La Plata drainage, the Hoplias malabaricus species group is constantly corroborated by morphological, cytogenetic and molecular evidence, and a recognition and taxonomic delineating of new entities is currently in progress (Rosso et al. 2018). Additionally, the nominal species name Hoplias malabaricus (Bloch) should be applied exclusively to the Guiana shield lineage (Rosso et al. 2018). Similarly, some authors (see Buckup 1992) suggest that populations of Characidium zebra Eigenmann throughout South America represent more than one species. Characidium zebra was described in tributaries of the Branco River (Negro River system) in the Amazon. Recent evidence suggests that C. zebra populations in the San Francisco and Paraná rivers correspond to the same species (Serrano et al. 2018) distinct from the C. zebra populations of the Amazon drainage.

Figure 6. 

Characiformes collected in the Uberaba River. 1 Leporinus amblyrhynchus 2 Steindachnerina insculpta 3 Leporinus striatus 4 Leporinus friderici (uncataloged) 5 Leporinus octofasciatus 6 Hoplerythrinus unitaeniatus 7 Schizodon nasutus 8 Prochilodus lineatus 9 Hoplias intermedius 10 Hoplias aff. malabaricus 11 Brycon nattereri 12 Apareiodon piracicabae 13 Galeocharax gulo 14 Apareiodon affinis 15 Apareiodon ibitiensis 16 Astyanax lacustris 17 Astyanax paranae 18 Astyanax aff. paranae 19 Parodon nasus 20 Metynnis lippincottianus 21 Astyanax aff. fasciatus 22 Astyanax bockmanni 23 Bryconamericus turiuba 24 Myloplus tiete 25 Hasemania uberaba 26 Hyphessobrycon uaiso 27 Oligosarcus pintoi 28 Knodus aff. moenkhausii 29 Piabarchus stramineus 30 Piabina argentea 31 Serrasalmus maculatus 32 Crenuchidae (undescribed genus and species) and 33 Characidium aff. zebra. Photographs are of specimens presented in Table 2. Scale bar: 10 mm.

Figure 7. 

Siluriformes (Loricariidae absent), Gymnotiformes, Cichliformes, Cyprinodontiformes, and Synbrachiformes collected in the Uberaba River. 1 Megalechis thoracata 2 Tatia neivai 3 Trichomycterus candidus 4 Trichomycterus brasiliensis 5 Imparfinis borodini 6 Rhamdiopsis sp. 7 Corydoras difluviatilis 8 Aspidoras fuscoguttatus 9 Rhamdia quelen 10 Pimelodella avanhadavae 11 Eigenmannia trilineata 12 Gymnotus sylvius 13 Gymnotus inaequilabiatus (uncataloged) 14 Crenicichla jaguarensis 15 Crenicichla britskii 16 Cichla piquiti 17 Geophagus brasiliensis 18 Coptodon rendalli 19 Oreochromis niloticus (uncataloged) 20 Cichlasoma paranaense 21 Phalloceros harpagos (female above and male below) 22 Poecillia reticulata (female above and male below) 23 Melanorivulus giarettai (male above and female below) and 24 Synbranchus marmoratus. Photographs are of specimens presented in Table 2. Scale bar: 10 mm.

Astyanax aff. paranae Eigenmann collected from the Uberaba River may represent a distinct species in the complex “Astyanax scabripinnis species complex” sensu Moreira-Filho and Bertollo (1991), a group with an underestimated diversity (Bertaco and Malabarba 2001) as it differs by a number of features (e.g., eye coloration and some measurements). Knodus moenkhausii (Eigenmann & Kennedy) was described from the Arroyo Trementina in the Paraguay River system. The specimens from the Upper Paraná River and identified so far as K. moenkhausii apparently represents an undescribed species (F. R. Carvalho pers. comm.).

The taxonomic boundaries of the Hypostomus species are unclear. Some species of the genus Hypostomus are highly variable morphologically and widely distributed. In addition, some important diagnostic characters, such as color pattern, cannot be seen at present in type specimens collected more than 100 years ago, making identification of the species difficult (Zawadzki et al. 2004). For example, Hypostomus hermanni Ihering is widely distributed within the Upper Paraná River system. A comparison of the specimens collected in the Uberaba River with specimens from other locations revealed a discrepancy in some meristic and color traits. The Uberaba specimens are especially different from specimens from the Piracicaba River, the type locality of H. hermanni. It has been also shown that different populations of Hypostomus paulinus (Ihering) are effectively reproductively isolated and characterized by a high degree of inbreeding (Zawadzki et al. 2004).

The occurrence of Metynnis lippincottianus may be a result of accidental introduction (Ota 2015). Among the allochthonous species, Poecilia reticulata was introduced to control mosquito larvae (Ota et al. 2018). Cichla piquiti was probably introduced for sport fishing (Langeani et al. 2007; Ota et al. 2018), and Gymnotus inaequilabiatus originally from the Lower Paraná River, Paraguay and Uruguay rivers (Maxime and Albert 2014), colonized the upper reaches of the Paraná River after the construction of the Itaipu hydroelectric dam in the 1980s. Ota et al. (2018) suggested that the occurrence of Hoplerythrinus unitaeniatus in the Upper Paraná River can be associated with its introduction as a live bait or after inundation of the Sete Quedas Falls after the construction of the Itaipu dam. Galeocharax gulo is widely distributed in almost all Upper Amazon River systems, also in the Orinoco, Oyapok, Araguaia-Tocantins, and Paraná rivers (Giovannetti et al. 2017). The occurrence of this species in the Upper Paraná system may be a result of natural dispersion. Coptodon rendalli and O. niloticus probably represent results of escapes from fish farms (Langeani et al. 2007; Ota et al. 2018) and the populations of both species are probably established in the region as they have been regularly registered since long ago. Finally, Souza et al. (2016) report the occurrence of Cyphocharax nagelii (Steindachner) and Steindachnerina brevipinna (Eigenmann & Eigenmann) in the system, but we could not confirm these data and refrained from including them in the species list.

New taxa have been described from the Uberaba River system over the past decade, e.g., Hasemania uberaba (Serra and Langeani 2015), Hyphessobrycon uaiso (Carvalho and Langeani 2013), and Microlepidogaster dimorpha (Martins and Langeani 2011). These newly described species are only known from their type localities or from a few localities corroborating several examples of endemism in the Upper Paraná River, previously indicated by some authors (e.g., Langeani et al. 2007). This clearly demonstrates the importance of inventories and consequent conservation measures. Two species registered in the Uberaba River are definitely threatened: Brycon nattereri Günther and Myloplus tiete (Eigenmann & Norris) are assigned to “Vulnerable” (VU) and “Endangered” (EN) respectively, on the IBAMA Red List of Endangered Species (ICMBio 2015). The main threats to the local fauna are related to changes in hydrological cycles and the loss of riparian vegetation, as well as overexploitation of natural stocks (Lima et al. 2008; Lima et al. 2015). In addition, the presence of migratory rheophilic species such as Prochilodus lineatus (Valenciennes), Leporinus friderici (Bloch), B. nattereri, and M. tiete, is because these species use local resources, at least partially, to complete their life cycle, as suggested by Carolsfeld et al. (2003). Considering all the factors discussed above, the Uberaba River contains a diverse and heterogeneous fish fauna, with two endemic species, H. uberaba and an undescribed crenuchid (a description is in the process by Ribeiro et al.) and a low number of allochthonous and exotic species. The Uberaba River has undergone several anthropogenic actions over the last decades, such as the increase of the area destined to grazing, resulting in only 17.7% of native vegetation remains (Valle-Junior et al. 2010) and the reduction of the lotic environments due to damming. The impact of human-induced environmental change is dramatic on the structure and composition of the local fauna. Development of management plans on conservation areas such as the implementation of “Area de Proteção Ambiental Rio Uberaba – APA-Rio Uberaba” project (SEMEA 2004) is necessary to mitigate the effects and help the sustainable use of local natural resources.

Figure 8. 

Loricariidae, genus Hypostomus collected in the Uberaba River (dorsal, lateral, and ventral photographs). 1 Hypostomus ancistroides 2 Hypostomus albopunctatus 3 Hypostomus strigaticeps 4 Hypostomus margaritifer 5 Hypostomus butantanis 6 Hypostomus regani 7 Hypostomus aff. paulinus 8 Hypostomus topavae and 9 Hypostomus nigromaculatus, Photographs are of specimens presented in Table 2. Scale bar: 10 mm.

Figure 9. 

Another loricariids collected in the Uberaba River (dorsal, lateral, and ventral photographs). 1 Hypostomus aff. hermanni 2 Hypostomus fluviatilis 3 Rineloricaria latirostris 4 Proloricaria prolixa 5 Curculionichthys insperatus 6 Microlepdogaster dimorpha and 7 Loricaria lentiginosa (uncataloged). Photographs are of specimens presented in Table 2. Scale bar: 10 mm.

We thank Fernando Carvalho, Fernanda Martins, and Claudio Zawadzki for help with species identification; Felipe Montefeltro, Nivaldo Urzulin, and Cristiéle Ribeiro for proofreading; Cristiane Santos, Simony Santos, Ronaldo Santos, Flavienne Carvalho, Gustavo Carvalho, and Luciano Henrique for the help in the field work; José Noel Prata, Paulo César Macedo, Vander Neto, Mario Cesar, Eliana Miranda Araújo, and Pedro César Chagas for support in various activities throughout the work. We are grateful for the support given by the Military Police of Minas Gerais (16° Pel. and 5ª Cia PM Ind. MAmb. de Planura). This project was partially funded by Prefeitura Municipal de Uberaba. DCR and MRT were supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes) and JMAC and FL by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). The manuscript benefitted from reviews by Carla Pavanelli, Nina Bogutskaya, Nathalie Yonow, and anonymous referees.