Authors: Rosalía Aguilar-Medrano, María D. Blanqueto-Manzanero, María E. Vega-Cendejas

A central objective of ecological research is to understand the causes and links of diversity. Trophic and morphological variation has been recognized as the baseline to determine communities’ functional arrangement; however, few morphological structures have been explored. In the present study, the fish assemblage of two contrasting localities within the Gulf of Mexico, the Campeche Bank (CB) and the Perdido Fold Belt (PFB), was examined to (1) analyse and compare the size, weight, trophic, and morphological (fish body and otolith) variation and (2) test if the otoliths morphological variation can be used to estimate the fish-body variation. Fish and otolith size, fish and stomach–intestine weight, and stomach content were determined and geometric morphometric methods were applied to the fish body and otoliths. The fish body shows a relationship with the weight measurement and the otolith size, no differences in these variables were found between the two localities. In both localities Annelida, Mollusca, Osteichthyes, and Crustacean are the most common preys; however, the CB assemblage was more diverse in both diet and morphology and six trophic groups and 18 ecomorphological groups were determined, while in PFB, four trophic groups and 13 ecomorphological groups were determined. Finally, according to the morphological comparison in both localities, the otolith variation can be used to estimate the fish-body morphological diversity. This study reports important information in the understanding of the links between morphological structures and highlights the importance of the otoliths as a morphological variable that reflects a wide range of ecomorphological variation of the fish body.

Keywords: Campeche Bank, geometric morphometric, otolith, Perdido Fold Belt, trophic diversity