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.Keywords: Alvarado River drainage, Community ecology, Habitat use, Morphological diversity, Neotropical region.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.Palabras clave: Cuenca del río Alvarado, Diversidad morfológica, Eco...

Hemibrycon iqueima sp. nov., is described from small streams in the Magdalena drainage at the foothills of the western slope of the Eastern Cordillera of the Colombian Andes, Suarez municipality, Tolima Department, Colombia. The new species is distinguished from its congeners in the Magdalena-Cauca River basin by a combination of characters related to snout-anal-fin origin length, head length, dorsal-pectoral fin distance, dorsal-fin-hypural distance, postorbital distance, orbital diameter, snout length, number of total vertebrae, pre-dorsal scales, scale rows between anal-fin origin and lateral line, number of branched rays of the anal fin, maxillary teeth number and number and arrangement of hooks on the branched rays of the pectoral and dorsal fins. In addition, the validity of this species is supported by previous molecular analyses that included specimens of the new species that had been erroneously identified. Phylogenetic relationships between the new species and congeners from Pacific coast basins are discussed.

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Catfishes of the family Astroblepidae form a group composed by 82 valid species of the genus Astroblepus inhabiting high-gradient streams and rivers throughout tropical portions of the Andean Cordillera. Little has been advanced in the systematics and biodiversity of astroblepids other than an unpublished thesis, a single regional multilocus study and isolated species descriptions. Here, we examined 208 specimens of Astroblepus that apparently belong to 16 valid species from several piedmont rivers from northern Colombia to southern Peru. Using three single-locus approaches for species delimitation in combination with a species tree analysis estimated from three mitochondrial genes, we identified a total of 25 well-delimited lineages including eight valid and 17 potential undescribed species distributed in two monophyletic groups: the Central Andes Clade, which contains 14 lineages from piedmont rivers of the Peruvian Amazon, and the Northern Andes Clade with 11 lineages from trans- and cis-Andean rivers of Colombia and Ecuador, including the Orinoco, Amazon, and Magdalena-Cauca basins and Pacific coastal drainages. Results of species delimitation methods highlight several taxonomical incongruences in recently described species denoting potential synonymies.

A new species of Hemigrammus is described from the Amazon Basin near Leticia, Departamento Amazonas, Colombia. In common with some congeners and some Hyphessobrycon spp., the new species colour pattern lacks a humeral blotch but has a caudal-peduncle blotch. It can be distinguished from congeners with a similar colour pattern by having: a relatively deep body (30.2%-39.0% L S ), 20-24 branched anal-fin rays, 6-8 perforated scales of the lateral line, anal-fin base without a conspicuous black stripe, 3-5 maxillary teeth, maxillary teeth with 1-3 cusps, a thin longitudinal midlateral line and a well-defined oval shaped caudal blotch, extending from caudal peduncle into the lower caudal-fin rays. Comparisons with congeners and with Hyphessobrycon species sharing the same general colour pattern are presented. K E Y W O R D S freshwater fishes, Hemigrammus tridens group, Río Amazonas, Stethaprioninae, taxonomy

A new species of Creagrutus is described from several localities in the upper Río Magdalena drainage, Colombia. Creagrutus dulima n. sp. differs from all trans-Andean congeners by the combination of a relatively small orbital diameter, the shape and position of hooks on the pelvic-fin rays, in having the third infraorbital not in contact with the preopercle ventrally, and the presence of a dark, reticulated pigmentation pattern on the dorsal portion of body. The distribution of Creagrutus species in the Magdalena-Cauca River Basin is discussed, and an updated identification key for species of trans-Andean Creagrutus is provided.

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A new species of Pimelodella is described from northern coastal drainages of the Sierra Nevada de Santa Marta (SNSM), Colombia. The new species is diagnosed from all trans-Andean congeners by the following unique combination of characters: head length 22.2–23.7% SL, bony interorbital width 17.6–21.6% HL, maxillary barbels length 53.0–68.3% SL, inner mental-barbels length 14.4–20.0% SL, body width 17.6–21.1% SL, dorsal-fin spine length 8.3–13.7% SL, dorsal-fin base 12.3–14.9% SL, pectoral-fin spine length 12.9-14.5% SL, pectoral-fin spine length without dentations on the distal posterior margin 21.6–29.8% in pectoral-fin spine length, maximum depth of dentations in posterior margin of pectoral-fin spine 1.40–1.68 times in the width of the spine at its base, adipose-fin base length 22.8–26.4% SL, caudal-peduncle depth 9.2–10.5% SL, 40 vertebrae, having a conspicuous paired dark brown stripe on the dorsal surface of body, extending from posterior margin of head to caudal-fin insertion and a wide dark brown midlateral stripe present. The isolated occurrence of this new taxon living in allopatry in coastal drainages of the SNSM could have interesting biogeographic implications for dispersal and vicariance processes of the ichthyofauna from northern South America.