Diet and morphology through ontogeny of the nonindigenous Mayan cichlid 'Cichlasoma (Nandopsis)' urophthalmus (Gunther 1862) in southern Florida

We evaluated diet and morphology through ontogeny for a freshwater population of the Mayan cichlid 'Cichlasoma (Nandopsis)' urophthalmus (Gunther 1862) in Florida's Big Cypress National Preserve. This species is a generalist predator throughout ontogeny. Fish remained the primary prey item throughout ontogeny, but there was a shift from detritus and ostracods among juveniles to algae, gastropods (snails), decapods, Hymenoptera, and adult Diptera among adults. All morphological variables grew isometrically except total molariform tooth area and pharyngeal jaw mass, which exhibited positive allometry. Despite a moderately robust adult pharyngeal jaw apparatus, this species does not specialize on hard prey at this south Florida site. Compared to its native range in Mexico, fish in Florida have undergone a pronounced niche shift with the diet being dominated by fish and snails, probably due to greater availability. The invasive success of C. urophthalmus does not appear to be related to ontogenetic morphological shifts or dietary specialization. Rather, its successful and rapid colonization of southern Florida might in part be related to its generalized and opportunistic feeding habits and morphology.