ANÁLISE MORFOMÉTRICA DE Gymnotus inaequilabiatus (VALENCIENNES, 1839) (GYMNOTIFORMES: GYMNOTIDAE) EM DIFERENTES BACIAS HIDROGRÁFICAS

Os Gymnotiformes são conhecidos como peixes elétricos, peixes faca, tuviras ou morenitas, constituindo uma pequena e endêmica porção da ictiofauna Neotropical. Por apresentar uma ampla distribuição geográfica e uma alta riqueza, Gymnotus é o gênero da ordem mais estudado. Uma das espécies que mais se destaca é Gymnotus inaequilabiatus a qual é distribuída nas bacias dos rios Paraná-Paraguai e drenagens costeiras do Uruguai e dos rios do sudeste Brasileiro. Com base em relatos de introdução desta espécie e divergências moleculares em várias bacias hidrográficas, traçou-se a hipótese de que há variação morfológica entre as populações de G. inaequilabiatus oriundas de diferentes bacias. Portanto, objetivou-se analisar morfometricamente as populações de quatro bacias diferentes. Para a avaliação e interpretação dos dados morfométricos foram realizadas análises de componentes principais e análises de variáveis canônicas. As análises não mostraram diferenças significativas entre as populações. Contudo, na análise das variáveis canônicas nota-se uma leve tendência na separação das populações. Os resultados demonstraram que Gymnotus inaequilabiatus não se difere morfologicamente e que não há possibilidade de inferência taxonômica sobre as populações das bacias analisadas, não corroborando com a hipótese inicial. No entanto, os resultados sugerem que G. inaequilabiatus apresenta uma alta capacidade adaptativa, grande capacidade de colonização e resiste a diferentes pressões ambientais.Palavras-chave: alto rio Paraná, morfologia, peixes faca, peixe elétrico, rio Paraguai.The Gymnotiformes are usually known as electric fishes, knife fishes, tuvira or morenitas, constituting a small and endemic portion of the Neotropical ichthyofauna. Among your genus, by presenting a broad geographic distribution and  high richness, Gymnotus is the most studed. One of the species that more stands out is the Gymnotus inaequilabiatus wich is distributed in the Paraná-Paraguai, Coastal Rivers, Uruguay and Brazilian southeastern Rivers Basins. Based in reports of molecular divergences and introduction of this specie in several drainage basins, was traced a hypothesis that exists morphologic variation between populations of G. inaeaquilabiatus from different river basins. To evaluation and interpretation of the morphometric data were realized of principal components analysis and canonical variable analysis. The analysis showed no significant differences between the populations of G. inaequilabiatus from the different river basins. However, the canonical variable analysis analysis presented a slight tendency in the separation of the populations. The results show that Gymnotus inaequilabiatus not differ morphologically and that there is no possibility of the taxonomy inference about populations of the analyzed basins, no corroborating with the initial hypothesis. However, suggests that G. inaequilabiatus has a high adaptive capacity, great capacity for colonization and resistant to different environmental pressures.Keywords: upper Paraná river, morphology; knife fish; electric fish; Paraguai river.

ECOMORPHOLOGICAL VARIATION IN Astyanax aff. paranae EIGENMANN, 1914, POPULATIONS IN THE UPPER PARANÁ RIVER BASIN

Astyanax paranae Eigenmann, 1914 é um pequeno caracídeo conhecido como lambari-do-rabo-vermelho, ocorrendo em vários rios das sub-bacias do alto rio Paraná. Tendo em vista que as características ambientais como disponibilidade de recursos, diversidade de habitats entre outras podem selecionar atributos específicos possibilitando diferenciações morfológicas, testamos a hipótese de que ambientes diferentes podem influenciar características ecomorfológicas distintas entre as populações. Analisamos a ecomorfologia de Astyanax aff. paranae oriundos de três córregos localizados no município de Apucarana pertencentes a diferentes bacias hidrográficas: córregos Jurema (bacia do rio Pirapó), Biguaçú (bacia do rio Ivaí) e Japira (bacia do rio Tibagi). Para testar as diferenças foram utilizados 15 exemplares de A. aff. paranae de cada população, sendo tomadas 26 medidas morfométricas e calculadas seis áreas, de maneira que foram calculados 22 índices ecomorfológicos. Para evidenciar diferenças ecomorfológicas entre os espécimes foram realizados Análises de Variáveis Canônicas (AVC) e um teste “post hoc” de comparações pareadas de Hotelling. Na análise de comparações pareadas entre as populações de A. aff. paranae nos córregos amostrados, o córrego Japira apresentou diferenças estatísticas significantes em relação ao córrego Biguaçú. As diferenças ecomorfológicas entre as populações do córrego Biguaçu e as dos córregos Jurema e Japira podem estar relacionadas com as características biogeográficas de cada bacia. Além disso, as particularidades de cada ambiente, como as interações bióticas e abióticas provida pela qualidade ambiental nos córregos Jurema e Japira podem ser influências, mesmo que de maneira discreta, frente às peculiaridades ecológicas de cada organismo.Palavras-chave: córregos, rio Ivaí, rio Paranapanema, isolamento geográfico, qualidade ambiental.Astyanax paranae Eigenmann, 1914 is a small characid known as lambari-do-rabo-vermelho that occurs in several rivers of Upper Paraná River Basin. Considering that environmental characteristics as resource availability, habitat diversity and many others may select specific attributes enabling morphological differentiation, we tested the hypothesis that different environments may influence distinct ecomorphological characteristics between populations. We analyzed Astyanax aff. paranae belonging to three streams from different basins in the Apucarana city: Jurema (Pirapo river basin), Biguaçu (Ivai river basin) and Japira (Tibagi river basin) streams. To test the ecomorphological difference we used 15 individuals of A. aff paranae of each population, to take 26 morphometric measures and calculate six areas, obtaining 22 ecomorphological rates. We used Canonical Variate Analysis (CVA) and a paired Hotelling’s test to evidence ecomorphological differences between the specimens. Japira stream’s population of A. aff. paranae presented statistical difference when compared with Biguaçu stream by the analysis of paired comparisons. The ecomorphological diferences between A. aff paranae`s population of Jurema and Japira and Biguaçu`s population may be related with the biogeographical characteristics of each river basin. Furthermore, particularities provided by the environmental quality as biotic and abiotic interactions may influence, even that slightly, the ecological differences among each organism.Keywords: streams; Ivaí river; Paranapanema river; geographic isolation; environmental quality

DNA Barcoding of Pyrrhulina australis (Characiformes: Lebiasinidae) reveals unexpected cryptic diversity in the group

Abstract The family Lebiasinidae includes a number of miniature and medium-sized fish species that are endemic to the Neotropical region. Pyrrhulina is the second most speciose lebiasinid genus and it is also the one with the most taxonomic uncertainties. In this context, the present study focused on the Pyrrhulina morphospecies found in a number of different drainage basins in South America to test the alternative proposals on the arrangement of the taxonomic units found within what is assumed to be a single nominal species, Pyrrhulina australis, based on a DNA Barcoding approach. The results of the analyses indicate that Pyrrhulina australis is a species complex, with intraspecific (within-group) genetic distances of up to 3.74%, well above the Optimal Threshold of 1.79% defined in the present study. The species delimitation analyses revealed a surprising level of diversification among the morphospecies evaluated, in particular, in the clade that encompasses Pyrrhulina australis (from the Paraguay River) + P. cf. rachoviana (Lower Paraná River), P. aff. australis I (Araguaia River)/II (Paraguay River)/III (Upper Paraná River)/IV(Guaporé River),and P. marilynae (Teles Pires River), which were arranged in six distinct evolutionary lineages that align with the geographical distribution of the respective drainage basins

Description of a new species of Hisonotus (Loricariidae: Siluriformes) from rio Araguaia basin

Ribeiro-Silva, Luís R., Silva, Gabriel S. C., Venere, Paulo C., Silva, Hugmar Pains Da, Roxo, Fábio F. (2020): Description of a new species of Hisonotus (Loricariidae: Siluriformes) from rio Araguaia basin. Zootaxa 4860 (4): 553-562, DOI: https://doi.org/10.11646/zootaxa.4860.4.

The Silent Threat of Non-native Fish in the Amazon: ANNF Database and Review

Non-native fish (NNF) can threaten megadiverse aquatic ecosystems throughout the planet, but limited information is available for the Amazon Region. In this study we review NNF data in the Amazonian macroregion using spatiotemporal records on the occurrence and the richness of NNF from a collaborative network of 35 regional experts, establishing the Amazon NNF database (ANNF). The NNF species richness was analyzed by river basin and by country, as well as the policies for each geopolitical division for the Amazon. The analysis included six countries (Brazil, Peru, Bolivia, Ecuador, Venezuela, and Colombia), together comprising more than 80% of the Amazon Region. A total of 1314 NNF occurrence records were gathered. The first record of NNF in this region was in 1939 and there has been a marked increase in the last 20 years (2000–2020), during which 75% of the records were observed. The highest number of localities with NNF occurrence records was observed for Colombia, followed by Brazil and Bolivia. The NNF records include 9 orders, 17 families and 41 species. Most of the NNF species are also used in aquaculture (12 species) and in the aquarium trade (12 species). The most frequent NNF detected were Arapaima gigas, Poecilia reticulata and Oreochromis niloticus. The current data highlight that there are few documented cases on NNF in the Amazon, their negative impacts and management strategies adopted. The occurrence of NNF in the Amazon Region represents a threat to native biodiversity that has been increasing “silently” due to the difficulties of large-scale sampling and low number of NNF species reported when compared to other South American regions. The adoption of effective management measures by decision-makers is urgently needed and their enforcement needed to change this alarming trend and help protect the Amazon’s native fish diversity.