NEOTROPICAL FRESHWATER FISHES: A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.

First record of Jupiaba acanthogaster (Eigenmann, 1911) (Ostariophysi, Characidae) in the upper Paraná river basin, Brazil

Jupiaba Zanata, 1997 is a genus with small species within Characidae, identified by a pair of modified bones in the form of spines just anteriorly to pelvic-fin base. The genus is mostly distributed throughout the Amazon drainage, except J. acanthogaster (Eigenmann, 1911), which also occurs in the Paraguay river basin. In this work, we recorded for the first time J. acanthogaster in the Sucuriú River drainage, upper Paraná river basin, Brazil. Its occurrence may be a consequence of the historical hydrological interaction between the Paraná and Paraguay river basins.

First record and extended distribution of Otothyropsis piribebuy (Loricariidae: Hypoptopomatinae) in Brazil

Cascudinhos are a group of small benthic fishes included in the Hypoptopomatinae subfamily, inhabiting small to moderate streams and rivers within the Neotropical region, from Venezuela to Northern Argentina. Until now, Otothyropsis piribebuy originally described from the rio Paraguay basin, in Paraguay, is the only species of the genus not recorded in Brazil. Recent samples in the rio Tererê, rio Paraguay basin, Brazil, revealed a population of Otothyropsis with uncertain taxonomic identity. Therefore, the study aimed to unveil the distribution of Otothyropsis within Brazilian territory. External morphology, osteology, measurements, and counts (plates, teeth, and rays) of these specimens from rio Tererê were compared to data from the original description of O. piribebuy, and also with specimens of O. piribebuy sampled in Paraguayan territory. Observations indicated no differences among the analyzed specimens. Furthermore, a Principal Component Analysis (PCA), carried out using log-transformed measures from Brazilian and Paraguayan specimens, showed no separation of these populations, also indicating that all analyzed specimens pertain to the same species. Based on this, a prediction map of distribution, using Maximum Entropy, was produced. The correct identification of spatial range of occurrence is an essential step to ensure the conservation of species, and the extended distribution of Otothyropsis piribebuy was confirmed, enhancing the list of neotropical fish from Brazil.

Conservation status of Astyanax biotae (Characiformes: Characidae) in Mato Grosso do Sul, upper Paraná River basin, Brazil

Astyanax biotae é uma espécie originalmente descrita em um afluente do Rio Paranapanema, bacia do alto Paraná. Durante amostragens realizadas em drenagens dos rios Ivinhema e Verde, no sistema do alto Paraná, em Mato Grosso do Sul, exemplares de A. biotae foram coletados em cabeceiras de pequenos riachos e em lagoas de várzea, tanto em Unidades de Conservação como em áreas de agricultura intensiva. Os dados morfomerísticos de 20 indivíduos analisados foram similares aos da série-tipo. Exemplares testemunhos estão depositados nas coleções ictiológicas da UFMS (ZUFMS), UEMS (CPUEMS) e UNESP (DZSJRP). Com base nos critérios da IUCN, sugerimos sua classificação como Menos Preocupante (LC) no estado de Mato Grosso do Sul, considerando principalmente a inexistência de ameaças efetivas em duas das áreas de ocorrência da espécie, situadas dentro de Unidades de Conservação. No entanto, reforçamos a urgência em medidas para a proteção das regiões de cabeceiras de riachos, a fim de evitar o aumento do desmatamento, assoreamento e poluição agrícola, problemas recorrentes no Cerrado, que comprometem severamente a manutenção desses hábitats e suas espécies. É necessário investir em estudos sobre a biologia da espécie e ampliar as amostragens, buscando diminuir os vazios amostrais ainda existentes nas drenagens estaduais.

Unrecognized biodiversity in a world’s hotspot: three new species of Melanorivulus (Cyprinodontiformes: Rivulidae) from tributaries of the right bank of the Rio Paraná basin, Brazilian Cerrado

The genus Melanorivulus presents a wide geographical distribution in the Neotropical region. Among Melanorivulus, the M.pictus species group has currently 18 species distributed in the Brazilian Cerrado, mainly in the upper Rio Paraná basin, with some species occurrences in the upper Rio Araguaia and Tocantins. In the present study, we describe three new Melanorivulus species, belonging to the M.pictus species group from different drainages of the right bank of the Rio Paraná basin in Mato Grosso do Sul state, Brazil. These new species are easily distinguished from the others by their unique colour patterns. Melanorivulusinterruptus is distinguished from all species of the M.pictus group by the presence of oblique chevron-like red bars interrupted, mainly on the midline of the flank in males; while M.ivinhemensis by the yellow colouration of the caudal fin with thin red bars arranged only in the median region of the fin in males. Melanorivulusamambaiensis is distinguished from all species of the M.pictus species group by having an orange anal fin or sometimes more reddish-orange with distal margin grey or dark grey and chevron-like bars along the body, distinctly branched ventrally forming an inverted Y-shape in males. The high diversity of the Melanorivulus species with high levels of endemism demands the development of conservation strategies to avoid the loss of their vulnerable habitats in the Cerrado biome. We expect presence of more species of the M.pictus species group also along the lower reaches of the tributaries of the Rio Paraná. Additionally a dichotomic identification key of the M.pictus species group is provided.

Survey of fish species from plateau streams of the Miranda River Basin in the Upper Paraguay River Region, Brazil

Abstract The objective of this study was to provide a comprehensive list of the fish fauna of headwater streams of the Miranda River in the Upper Paraguay River Basin. Our primary data set was constructed from sampling of fish using a rectangular sieve, trawl, and gill nets from 2004 to 2015. Our secondary data were derived from published reports conducted in the Miranda River Basin, in addition to taxonomic and distribution data from other studies conducted in the basin. All data were compiled, which in the end encompassed a period from 1999 to 2015. The datasets yielded a total of 143 species, 104 from the primary data (72.7%) and 39 from the secondary data (27.3%). Species were distributed among seven orders and 30 families were found in the Miranda River Basin. Characiformes and Siluriformes were the predominant orders, and the families Characidae and Loricariidae had the greatest number of species. Our results indicate a greater number of species compared to other studies of the Upper Paraguay Basin headwaters, likely due to the longer time frame covered by our primary and secondary datasets.

Fishes from Baía da Medalha, southern Pantanal, Brazil: A 20 years review

Abstract Located in the Pantanal of Miranda-Abobral, the Baía da Medalha is the largest pond close to the Base de Estudos do Pantanal of the Universidade Federal de Mato Grosso do Sul. The Baía da Medalha has been a study site for several didactic and scientific projects for years. Nevertheless, its fish fauna has never been inventoried. Based on data collected from the beginning of the 1990s up to 2011, we provide a list of fish species from the Baía da Medalha. A total of 97 species were recorded, corresponding to about 40% of the species stated for the Pantanal. Characiformes and Siluriformes were the most species-rich orders, being Characidae and Cichlidae the families with the highest number of species. Regional seasonal flood dynamics and the abundance of aquatic macrophytes may be associated with this high diversity. The representative richness found in this lagoon highlights the importance of such taxonomic surveys to preserve the diversity of aquatic habitats within the Pantanal ecosystem.

First record of the camboatá Megalechis picta (Müller & Troschel, 1849) (Siluriformes: Callichthyidae) for the Pantanal, Brazil

Herein we report the first record of Megalechis picta in the Brazilian Pantanal based in a single specimen captured in a tributary to the rio Miranda, municipality of Corumbá, rio Paraguay basin, State of Mato Grosso do Sul, Brazil. Additional discussion about its co-occurrence with M. thoracata is also provided.

Ecomorphology and diet reflect the spatial segregation between two Siluriformes species inhabiting a stream of the Bodoquena Plateau, in Central Brazil

Pimelodella taenioptera Miranda Ribeiro, 1914 and Imparfinis schubarti (Gomes, 1956) are two of the most common fish species in Bodoquena Plateau streams, Paraguay basin. These species have benthic habits and subaquatical observations suggested that they present differentiation in their preference for mesohabitat types. Pimelodella taenioptera shows preference for slow waters, such as pools, while I. schubarti is associated to riffles. In this study we investigated if the known patterns of mesohabitat use of P. taenioptera and I. schubarti can be predict by their ecomorphological and trophic traits. We described the dietary habits and ecomorphological attributes of P. taenioptera and I. schubarti individuals, captured in the Parque Nacional da Serra da Bodoquena (PNSB), Mato Grosso do Sul state, central Brazil. Pimelodella taenioptera presented a more generalist diet, consuming a total of 23 different food items. Imparfinis schubarti have a diet based exclusively on aquatic insects. The ecomorphological analysis revealed that the species differed in relation to five morphological traits associated to habitat use (p <0.01). The results of this study reveal a clear functional dissimilarity between P. taenioptera and I. shubarti. The observed trophic and ecomorphological patterns are congruent with the known habitat use for these species and probably reflect the spatial and temporal variability on conditions and resources present in riffles and pools. Therefore, as expected, the morphological and feeding attributes represent predictive information related to mesohabitat use.

Ancistrus cuiabae Knaack, 1999 (Siluriformes: Loricariidae: Ancistrinae): first record for the Southern Pantanal

Ancistrus cuiabae, an easily identified species of armored catfish from the Upper Paraguay River basin has recently been described from the Cuiabá River basin. Its distribution was previously restricted to the state of Mato Grosso. However, here we report the southernmost record of this species, the first within the Mato Grosso do Sul State.

Geophagy in two parrot species in southern Pantanal, Brazil

Geophagy is a habit recorded for parrots, which seek earthy or soil-like substances presumably to help them in digestive functions, whether mechanical or chemical ones. Few studies are devoted to this feeding peculiarity in the Pantanal region. Here are reported two events of geophagy, for the Blue-and-yellow Macaw (Ara ararauna) and the Nanday Parakeet (Aratinga nenday) in the Pantanal subregions of the Miranda-Abobral and Nhecolândia, Mato Grosso do Sul, respectively.

Fruit-eating fishes of Banara arguta (Salicaceae) in the Miranda River floodplain, Pantanal wetland

The role of fish as frugivorous and its ecological consequences are often neglected in ecological studies. However, the importance of the interaction between fish and plants is gaining force in scientific literature, and fish has been considered effective seed dispersers. The fruit-eating fish assemblage of Banara arguta (Salicaceae) was evaluated in Southern Pantanal wetlands. Nine species were reported consuming fruits, with different strategies to capture them. The distribution of B. arguta associated with the Pantanal floodplain and the presence of several species of fruit-eating fish, suggest that ichthyochory can be an important seed dispersal strategy to B. arguta.