Morfometría de las especies de Vieja (Cichlidae) en ríos de la cuenca del Usumacinta, Chiapas, México

Abstract

We evaluated and compared morphological characteristics among the 6 species of Vieja Fernández-Yépez, 1969 from Usumacinta River. We analyzed 20 adults by specie, obtaining 33 measurements, which were standardized and analyzed with a discriminant analysis. We also performed a comparison of body shape among species, using the geometric morphometric analysis from digitalized images. Traditional and geometric morphometrics allowed distinguishing each taxa. We found 10 discriminants measures, related with the head region and length of fins, only mouth position was different among more taxa. In both analyses, similarity relationships showed 2 groups, being V. bifasciata (Steindachner, 1864) and V. synspila (Hubbs, 1935) the most similar species. Thin plate spline showed greater variation in the cephalic region, specifically in eyes and mouth position. Morphometries differences can be used for taxonomic identification in future works. The variation found in cephalic and trophic morphology can be a mechanism that promotes coexistence of species and explain the diversity of the group in this region.