Ecomorphology and Morphological Disparity of Caquetaia Kraussii (Perciformes: Cichlidae) in Colombia

SIMPLE SUMMARY: Morphological variation studies allow us to understand the mechanisms and factors that generate variations in populations, thus allowing the development of conservation plans and sustainable management of species. The “yellow mojarra”, Caquetaia kraussii (Perciformes: Cichlidae), is a species native to Colombia and Venezuela that recently has become an essential species in the food security of many Colombian fishing families. Geometric morphometrics (GM) is a tool that quantifies the variation of a shape through multivariate analysis, allowing its graphical and easy visualization. To measure the phenotypic variation of C. kraussii in different localities in “Canal del Dique”, Colombia, advanced morphological tools were used to quantify fish shape and evaluate associations between different ecological parameters of the study sites and the morphological differentiation of their populations. Morphological differences between localities were found and the influence of environmental parameters on the geometric shape of C. kraussii was also evidenced. These results demonstrates the efficiency of combined geometrics morphometrics with ecomorphological analysis to evaluate the impact of environmental pressures on fish body shape. ABSTRACT: Understanding the interspecific morphological variability of Caquetaia kraussii (Perciformes: Cichlidae) between different localities in its distribution range is becoming essential, as this species constitutes a valuable resource for the economy and subsistence of the local human communities where it is endemic in Colombia and Venezuela. In order to develop efficient farming and handling plans for this species, a deep understanding of the factors and mechanisms generating morphological variability is crucial. This study analyzes the morphological variability of C. kraussii by using geometric morphometrics in four localities distributed between the Dique and North channels, which are part of the Bolívar department in Colombia. Likewise, the effect of environmental variables such as temperature (T°), dissolved oxygen (OD) and pH on morphological variability was analyzed using a partial least squares approach. The results show that environmental stress has an influence on ~10% of the body shape of C. kraussii, whereas ~90% of the body shape is not directly influenced by environmental parameters, suggesting an effect from stress related to sexual dimorphism. Similarly, the analyses show shape variation among localities, mainly between populations of lotic environments and those of lentic environments. This morphological disparity seems to be subject to environmental and sexual stresses in the different localities.