Shells, teeth and DNA: land snails from an urban forest in Rio de Janeiro, SE Brazil

This study aims to explore the diversity of land snails in a forested area of the second largest Brazilian city (Rio de Janeiro), through the study of basic morphology (ie shell, operculum, jaw and radula) and the barcode of COI sequences. The conservation unit ‘Parque Natural Municipal da Cidade’ (PNM da Cidade) is a fragment of the Atlantic Forest biome. During 12 fieldwork visits, 17 species of terrestrial gastropods were found in PNM da Cidade, of which six are synanthropic, exotic/cryptogenic, and occurred in single or few sampling stations, whereas the 11 native species varied in their range. PNM da Cidade houses a large population of the native species Thaumastus cf. taunaisii (Férussac, 1822), always found close to water sources, but it demands conservation concern. The sampling of live specimens allowed the study of operculum, jaw or radula from five selected species, and the generation of 20 COI sequences from 10 species, elucidating taxonomic aspects. The gastropod fauna at PNM da Cidade is indicative of moderately preserved habitats, despite some anthropic pressure. Future geography-based studies of land snails could add DNA sequences in order to enable the discovery or elucidation of cryptic complexes of species.