Fish functional trophic groups in headwater karst streams from the Upper Paraguay River basin

Data obtained by direct observation of organisms in their natural habitats can provide valuable contributions regarding intra- and inter-specific interactions, as well as spatial distribution and trophic relationships. However, relatively few such data are available for the Neotropical ichthyofauna relative to the great species diversity of this region. We present data on the ichthyofauna in karst environments of the Serra da Bodoquena, Upper Paraguay River basin regarding their categorization into functional trophic groups. We used direct observations that focused on the most frequent feeding tactics and their spatial (vertical and horizontal) distribution in the channel. We observed 83 fish species in 17 functional trophic groups. The greatest species richness was concentrated in the Characidae and Loricariidae in the categories Diurnal Backwater Drift Feeders and Grazers, respectively. Regarding horizontal depth stratification, we found a positive relationship between the association of small fish with the shallow marginal habitats. This work represents a contribution to a region known for its high tourist potential and to the important diversity of the entire ichthyofauna of the Upper Paraguay basin region that requires proper conservation strategies for sustaining these species.(AU)

Dados obtidos pela observação direta dos organismos em seus hábitats naturais podem fornecer valiosas contribuições com relação a interações intra e inter-específicas, além de distribuição espacial e relações tróficas. Entretanto, relativamente poucos dados estão disponíveis no que diz respeito à ictiofauna neotropical dada à grande diversidade dessa região. Apresentamos dados sobre a ictiofauna em ambientes cársticos da Serra da Bodoquena, bacia do alto rio Paraguai e a categorização das mesmas em grupos tróficos funcionais baseada em observações diretas relacionadas às táticas alimentares mais frequentes e à sua distribuição espacial (vertical e horizontal) no canal. Assim sendo, observamos 83 espécies de peixes alocadas em 17 grupos tróficos funcionais. A maior riqueza de espécies concentrou-se nas famílias Characidae e Loricariidae, abrangendo as categorias Catadores Diurnos de Itens Arrastados pela Corrente e Pastadores, respectivamente. Com relação à estratificação horizontal, encontramos a relação positiva entre a associação de peixes de pequeno porte com relação aos hábitats marginais. Esse trabalho representa uma contribuição a uma região conhecida pelo seu alto potencial turístico e à importante diversidade da ictiofauna da região da bacia do alto Paraguai que requer estratégias de conservação adequadas para sustentar essas espécies.(AU)

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.

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

Abstract 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.

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.(AU)

Ecomorphology and diet reflect the spatial segregation between two Siluriformes species inhabiting a stream of the Bodoquena Plateau, in Central Brazil / Ecomorfologia e dieta refletem a segregação entre duas espécies de Siluriformes que habitam um córrego do Planalto da Bodoquena, no Brasil Central

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(AU)

Pimelodella taenioptera Miranda Ribeiro, 1914 e Imparfinis schubarti (Gomes, 1956) estão entre as espécies de peixe mais comuns nos riachos do Planalto da Bodoquena, bacia do rio Paraguai. Estas espécies compartilham hábito bentônico, entretanto observações subaquáticas sugerem que estas espécies apresentam diferenças na preferência por tipos de mesohábitats. Pimelodella taenioptera apresenta preferência por habitats lênticos, tais como poços, enquanto I. schubarti é associado a corredeiras. Neste estudo, investigamos se os padrões conhecidos de uso de mesohábitats de P. taenioptera e I. schubarti predizem suas características ecomorfológicas e tróficas. Descrevemos os hábitos alimentares e os atributos ecomorfológicos de indivíduos de P. taenioptera e I. schubarti, capturados no Parque Nacional da Serra da Bodoquena (PNSB), Estado do Mato Grosso do Sul, Brasil Central. Pimelodella taenioptera apresentou dieta mais generalista, consumindo um total de 23 itens alimentares. Imparfinis schubarti apresentou dieta exclusivamente composta por insetos aquáticos. A dieta de P. taenioptera foi mais variável na estação chuvosa do que na estação seca (p=0,05) e foi significativamente mais variável do que a dieta de I. schubarti (p 0,01). A variabilidade na composição da dieta entre indivíduos de I. schubarti não diferiu entre as estações (p=0,48). As análises ecomorfológicas revelaram que as espécies diferiram em relação a cinco traços morfológicos associados ao uso do hábitat (p 0,01). Os resultados obtidos neste estudo revelam uma clara diferenciação funcional entre P. taenioptera e I. shubarti. Os padrões tróficos ecomorfológicos observados são compatíveis com o uso de habitat conhecido para essas espécies e, provavelmente, reflete a variabilidade espacial e temporal nas condições e recursos presentes em corredeiras e poços. Dessa forma, conforme esperado, os atributos morfológicos e tróficos representam informações com poder preditivo relacionadas ao uso de [...](AU)

Ecomorphology and diet reflect the spatial segregation between two Siluriformes species inhabiting a stream of the Bodoquena Plateau, in Central Brazil / Ecomorfologia e dieta refletem a segregação entre duas espécies de Siluriformes que habitam um córrego do Planalto da Bodoquena, no Brasil Central

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

Pimelodella taenioptera Miranda Ribeiro, 1914 e Imparfinis schubarti (Gomes, 1956) estão entre as espécies de peixe mais comuns nos riachos do Planalto da Bodoquena, bacia do rio Paraguai. Estas espécies compartilham hábito bentônico, entretanto observações subaquáticas sugerem que estas espécies apresentam diferenças na preferência por tipos de mesohábitats. Pimelodella taenioptera apresenta preferência por habitats lênticos, tais como poços, enquanto I. schubarti é associado a corredeiras. Neste estudo, investigamos se os padrões conhecidos de uso de mesohábitats de P. taenioptera e I. schubarti predizem suas características ecomorfológicas e tróficas. Descrevemos os hábitos alimentares e os atributos ecomorfológicos de indivíduos de P. taenioptera e I. schubarti, capturados no Parque Nacional da Serra da Bodoquena (PNSB), Estado do Mato Grosso do Sul, Brasil Central. Pimelodella taenioptera apresentou dieta mais generalista, consumindo um total de 23 itens alimentares. Imparfinis schubarti apresentou dieta exclusivamente composta por insetos aquáticos. A dieta de P. taenioptera foi mais variável na estação chuvosa do que na estação seca (p=0,05) e foi significativamente mais variável do que a dieta de I. schubarti (p 0,01). A variabilidade na composição da dieta entre indivíduos de I. schubarti não diferiu entre as estações (p=0,48). As análises ecomorfológicas revelaram que as espécies diferiram em relação a cinco traços morfológicos associados ao uso do hábitat (p 0,01). Os resultados obtidos neste estudo revelam uma clara diferenciação funcional entre P. taenioptera e I. shubarti. Os padrões tróficos ecomorfológicos observados são compatíveis com o uso de habitat conhecido para essas espécies e, provavelmente, reflete a variabilidade espacial e temporal nas condições e recursos presentes em corredeiras e poços. Dessa forma, conforme esperado, os atributos morfológicos e tróficos representam informações com poder preditivo relacionadas ao uso de [...]