Ecologia comparativa e ecomorfologia de espécies de Gymnodactylus (Squamata: Phyllodactylidae) em áreas de Mata Atlântica e Caatinga de região setentrional do nordeste brasileiro

Abstract

The genus Gymnodactylus is endemic to Brazil and currently comprises five species, two of which are recorded for the state of Rio Grande do Norte, Gymnodactylus geckoides, predominant in the Caatinga, and Gymnodactylus sp. nov., endemic to the northeastern Atlantic Forest. In some areas of the Brazilian Northeast, such as the dune and restinga ecosystems of the Atlantic Domain in Rio Grande do Norte, these species occur in sympatry, which makes it important to know how they coexist and/or segregate their ecological niches, compared to the use of these niches in areas where only one of these species occurs. In this sense, the feeding ecology and habitat use of G. geckoides and Gymnodactylus sp. nov. were analyzed in two areas of the Atlantic Forest Domain and one of Caatinga. In one of the Atlantic Forest areas (Parque Estadual Dunas do Natal - PEDN), the species occur in sympatry, while in the other, Area de Proteção Ambiental Jenipabu (APAJ), only G. geckoides occurs, similar to the Caatinga area of Estação Ecológica Seridó (ESEC Seridó). As they use different habitats in these areas, the influence of habitats on the morphology of G. geckoides was analyzed. The specimens were captured manually for analysis of stomach contents, and data about the habitat and microhabitat where they were first sighted were recorded. To find out the diet, 105 stomachs were analyzed, 37 from G. geckoides from ESEC Seridó, 23 from G. geckoides from APAJ, 14 from Gymnodactylus sp. nov. and 31 from G. geckoides from PEDN. For analysis of ecomorphological variation, 10 morphometric variables of G. geckoides populations were used. At ESEC Seridó and APAJ, termites (Isoptera) were the most important prey in the diet of G. geckoides. At PEDN, the diet of G. geckoides was mainly composed of Hemiptera, while for Gymnodactylus sp. nov., Isoptera and Formicidae. Regarding electivity, of the 27 categories of prey available at ESEC Seridó, those preferred by the G. geckoides population were Dermaptera, Diplopoda and Isopoda; the other categories were considered rejected. For the APAJ population, out of 20 available prey categories, Blattodea, Coleoptera, Isoptera, Insect Larvae, Pseudoscorpiones and Scorpiones were preferred; Araneae and Hemiptera were slightly preferred and the others were rejected. For the PEDN, among the 20 available categories, the G. geckoides population demonstrated a preference for Hemiptera, Insect Larvae and Lepidoptera, while Gymnodactylus sp. nov. demonstrated to prefer prey such as Coleoptera, Dermaptera, Diptera and Isoptera. A high level of overlap in terms of food niche and total segregation in the spatial niche was found between the two species in sympatry in the PEDN: Gymnodactylus sp. nov. it inhabits areas of high forest and low forest, while G. geckoides was restricted to open areas of beach dunes. The population of G. geckoides in APAJ was recorded in restinga vegetation and in anthropic areas, while in ESEC Seridó, arboreal-shrub vegetation and rocky outcrops were the most used habitats. Due to their restricted occurrence in soilassociated microhabitats, both species were considered terrestrial, but, in sympatry, they segregate in terms of habitat use. Morphological variations were found between populations of G. geckoides from the Caatinga and the Atlantic Forest; for PEDN and APAJ, the morphometric profiles demonstrated similarity. The hind limbs of Atlantic Forest populations are more elongated than those of the Caatinga, demonstrating that the habitat used by the species influences their morphology.