Diet and ecomorphology of the ichthyofauna of Manantiales stream, Buenos Aires province, Argentina

Abstract

Diet and ecomorphology of the ichthyofauna of Manantiales stream, Buenos Aires province, Argentina. the present study addresses the correlation between diet and morphology of 19 fish species that inhabit the Manantiales stream at the headwaters of the samborombón river, Buenos Aires province, Argentina. the species were classified into four trophic groups: carnivores, omnivores, insectivores and detritivores-alguivores. twelve ecomorfologic attributes related to habitat use and feeding patterns were analyzed to distinguish ecomorphologic groups of species with the food consumed. Univariate and multivariate analysis techniques were used to determine groups of species using the ecomorfologic and diet attributes as descriptors. Carnivores were associated with well developed head, mouth, pectoral and caudal fins and usually presenting compressed bodies. omnivores were a more heterogeneous group. nektonic forms of this group were associated with a compressed body, lateral eyes and relatively small size of the pectoral fins and caudal fins; nektobentonic forms were associated with small mouth, fusiform body and long caudal peduncle; benthic forms were related to depressed body, dorsal eyes, ventral mouth and long digestive tract. the only nektonic species consuming insects on the surface is characterized by a strongly compressed body, lateral eyes, tail and big wide mouth facing up. the detritus-alguivores had a long digestive tract, mouth ventral or terminal and long caudal fin. the significant relationship between diet and ecomorphology allows to sustain that fish with similar diets converge towards common ecomorfologicic attributes.Key words: diet, morphology, multivariate analysis, samborombón river, Argentina.Resumen: se estudio la correlación entre dieta y morfología de 19 especies de peces del arroyo Manantiales, cabecera del río samborombón, provincia de Buenos Aires, Argentina. Las especies fueron clasificadas en cuatro grupos tróficos: carnívoros, omnívoros, insectívoros y detritívoros-alguívoros. se analizaron 12 atributos ecomorfológicos relacionados con el uso del hábitat y la alimentación con el fin de distinguir patrones ecomorfológicos de las especies y de las especies con el alimento consumido. se utilizaron técnicas de análisis univariado y multivariado para determinar agrupamientos de especies utilizando los atributos ecomorfológicos y la dieta como descriptores. Los carnívoros se relacionaron con un buen desarrollo de cabeza, boca, aletas caudal y pectoral; y en general con cuerpos comprimidos. Los omnívoros constituyeron un grupo más heterogéneo. Las formas nectóni-cas de este grupo se relacionaron con un cuerpo comprimido, ojos laterales y tamaño relativamente pequeño de las aletas pectorales y aleta caudal; las formas nectobentónicas se relacionaron con boca pequeña, cuerpo fusiforme y pedúnculo caudal largo; y las formas bentónicas, con cuerpo deprimido, ojos de posición dorsal, boca ínfera y tubo digestivo largo. La única especie nectónica consumidora de insectos sobre la superficie ...

Eugenol as anesthetic for Cnesterodon decemmaculatus (Cyprinodontiformes, Poeciliidae)

“…However, in our study, no significant differences were observed in size between males and females. This observation could potentially be attributed to the differences between studies conducted in a natural environment, [39][40][41] in contrast to controlled environmental conditions under which the fish were reared.…”