Spiny treasures of Gorgona Island: Unveiling the natural history secrets of the lizard Enyalioides heterolepis (Squamata: Hoplocercidae) in Colombia

Novel insights into the natural history of the spiny woodlizard or spiny dwarf iguana, Enyalioides heterolepis (Bocourt, 1874), are presented based on a distinctive population from Gorgona Island, Cauca department, Colombia. Between July 2023 and August 2024, diurnal and nocturnal field surveys were conducted, and some ecological and morphological data were recorded. E. heterolepis is a diurnal, terrestrial species that primarily uses leaf litter. However, it shifts to arboreal microhabitats at night for sleeping, perching on trunks and leaves of similar heights and diameters across sexes. The species exhibits sexual dimorphism in body size and ventral sexual dichromatism, as well as a low frequency of caudal autotomy in individuals. These findings contrast with patterns observed in other neotropical rainforest iguanian lizards (Anolis, Plica, Uracentron) and partially align with previous reports for this and other Enyalioides species. Additionally, results are discussed in the context of island-mainland differences in lizard population densities. Predation pressure, social behavior, and the ecological and evolutionary bases of sexual dimorphism and dichromatism are proposed as key factors influencing the ecological traits of this species.