Scielo RSS <![CDATA[Neotropical Ichthyology]]> http://www.scielo.br/rss.php?pid=1679-622520170004&lang=es vol. 15 num. 4 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.br/img/en/fbpelogp.gif http://www.scielo.br <![CDATA[Ecomorphological relationships of fish assemblages in a trans-Andean drainage, Upper Magdalena River Basin, Colombia]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000400204&lng=es&nrm=iso&tlng=es ABSTRACT Ecomorphological patterns of the fish community were evaluated in the trans-Andean Alvarado River drainage, Colombia. A total of 29 species using 25 ecomorphological indices were analyzed to test how well the ecomorphological patterns are related to the fish assemblage. Although a significant correlation was found (Mantel test) between morphological attributes and trophic guilds, habitat use and distribution across the altitudinal gradient, only the last two were significantly independent of the phylogenetic relationships (partial Mantel test). Regarding the ecomorphological space, two main trends were defined. First, benthic periphytivores and invertivores were characterized by having dorsal or dorsolateral eyes, labial appendages, depressed bodies and well-developed pectoral, ventral and caudal fins, which provide them the ability to stabilize over the substrate and make rapid movements. Second, nektonic detritivore-invertivores and insectivores were found to have laterally compressed bodies, lateral eyes and larger eyes and anal fins. These species use vision during predation, are good continuous swimmers and possess higher maneuverability and stability. These results show that the fish assemblages in the Alvarado River drainage are structured ecomorphologically mainly by habitat and the altitudinal gradient. Therefore, this is evidence of the importance of habitat structure to maintain the functionality of the ecosystem.<hr/>RESUMEN Se evaluaron los patrones ecomorfológicos de la comunidad íctica en la cuenca transandina del Río Alvarado, Colombia. Se analizaron 29 especies empleando 25 índices ecomorfológicos con el fin de evaluar los patrones ecomorfológicos con el ensamblaje de peces. A pesar de que se encontró una correlación significativa (Prueba de Mantel) de los atributos morfológicos con los gremios tróficos, preferencia de hábitat y la distribución de las especies a lo largo del gradiente altitudinal, solamente las dos últimas fueron independientes de la filogenia (Prueba parcial de Mantel). Con relación al espacio ecomorfológico dos patrones fueron identificados. Primero, las especies bentónicas perifitívoras e invertívoras, caracterizadas por ojos dorsales o dorsolaterales, cuerpos deprimidos y aletas desarrolladas, proporcionando la capacidad de estabilizarse sobre el sustrato y realizar movimientos rápidos. Segundo, especies nectónicas detritívoras-invertivoras e insectívoras con cuerpos comprimidos, ojos laterales y mayor área relativa de ojos y aleta anal; estos usan la visión durante la actividad predatoria, con mayor capacidad de maniobrabilidad y estabilización. Estos resultados muestran que el ensamblaje de peces en la cuenca está estructurado principalmente por el uso de hábitat y el gradiente altitudinal, esto podría ser evidencia de la importancia de la estructura del hábitat para garantizar la funcionalidad del ecosistema. <![CDATA[Molecular and taxonomic characterisation of introduced specimens of <em><strong><em>Poecilia reticulata</em></strong></em> in the lower Paraguay River basin (Cyprinodontiformes: Poeciliidae)]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000400205&lng=es&nrm=iso&tlng=es ABSTRACT Poeciliids comprise around 300 species inhabiting the fresh and brackish waters of the Americas and Africa. Poecilia reticulata is native to Northeastern South America and Trinidad and Tobago. In this paper, introduced specimens of P. reticulata collected in the lower Paraguay River in Argentina, were characterized by means of molecular and taxonomic approaches. We further explore, by means of DNA Barcoding, the singularity of the genetic identity of these specimens. Ocurrence of P. reticulata in the lower Paraguay River represents the first record of this species in Argentina. Thirteen individuals of P. reticulata were collected. DNA barcoding showed that all five specimens sampled belong to a single mitochondrial lineage, which was also present in 11 countries from five continents. The distance-based tree clearly grouped separetely four different clusters of P. reticulata when including public data. Genetic distance between the most divergent P. reticulata almost paralleled distance between this species and Poecilia mexicana and P. vivipara. Established populations from Paraguay could be one of the plausible sources for the introduced populations recorded in the lower Paraguay River. The presence of P. reticulata in an open waterway with known drainage to a natural stream is of major concern.<hr/>RESUMO Poecilídeos compreendem cerca de 300 espécies que habitam águas doces e salobras das Américas e África. Poecilia reticulata é nativa do nordeste da América do Sul e Trinidad e Tobago. Neste trabalho, espécimes introduzidos de P. reticulata coletados no baixo rio Paraguai na Argentina, foram caracterizados por meio de abordagens moleculares e taxonômicas. Exploramos ainda, por meio de DNA Barcoding, a singularidade da identidade genética destes espécimes. A ocorrência de P. reticulata no baixo rio Paraguai representa o primeiro registro dessa especie na Argentina. Treze indivíduos de P. reticulata foram coletados. O Barcoding mostrou que todos os espécimes pertencem a uma única linhagem mitocondrial, a qual está presente em 11 países dos cinco continentes. A árvore de distâncias agrupou separadamente quatro clusters diferentes de P. reticulata quando incluindo dados públicos. A distância genética entre os agrupamentos mais divergentes de P. reticulata quase igualou a distância entre esta espécie e Poecilia mexicana e P. vivipara. As populações estabelecidas no Paraguai poderiam ser uma das fontes plausíveis para as populações introduzidas registradas no baixo rio Paraguai. A presença de P. reticulata em um canal aberto com drenagem conhecida para um córrego natural é de grande preocupação.