Morphological correlates of diet in an assemblage of West African freshwater fishes

Morphological correlates of diet were sought among 18 species of distantly related freshwater fishes from Guinea (West Africa). With regard to the per centage occurrence of six food items, the studied species could be classifi ed into four broad trophic categories reflecting what was eaten and where: detritivores. piscivores, surface feeders and benthic invertivores. Detrivo ry was associated with a high relative gut length and eyes in a dorsal posi tion: piscivory with large body and mouth size; surface feeding with a dors ally orientated mouth; and benthic invertivory with eyes in a lateral posit ion and small relative gut length. Similarity in diet and in morphology wer e both significantly correlated with taxonomic relatedness. Nevertheless, w hen taxonomic relatedness was accounted for, the relationship between obser ved similarity in diet and similarity in diet predicted from morphology was still significant. This result leads to the conclusion that species having similar diet lend to converge for some morphological attributes. (C) 1999 The Fisheries Society of the British Isles.