iNaturalist as a tool in the study of tropical molluscs

Although terrestrial gastropods are remarkably diverse, our knowledge of them is still lacking, especially for species from the Global South. As such, new tools to help researchers collect data on these organisms are very welcome. With this in mind, we investigated Brazilian observations on iNaturalist to assess the feasibility of the data available on the platform as a basis for studies on the tropical terrestrial gastropod fauna. The observations on iNaturalist were filtered by country, Brazil, and higher taxa, namely Eupulmonata, Cyclophoroidea and Helicinoidea, yielding a sample of 4,983 observations. These observations were then reviewed in search of records of rare or little-known species, species found outside their previously known range, and interesting ecological interactions. Exotic species made up 35% to 39% of the sampled iNaturalist records. The most commonly observed species were Lissachatina fulica (Bowdich, 1822), Bradybaena similaris (Férussac, 1822), Drymaeus papyraceus (Mawe, 1823), Drymaeus interpunctus (E. von Martens, 1887), Limacus flavus (Linnaeus, 1758), Meghimatium pictum (Stoliczka, 1873), Cornu aspersum (O. F. Müller, 1774), Vaginulus taunaisii (Férussac, 1821), Ovachlamys fulgens (Gude, 1900), and Bulimulus tenuissimus (Férussac, 1832). In total, 166 observations were deemed of interest to our purposes (e.g., rare species, range extensions, ecological interactions), totalling 46 identified species and 16 observations identified at genus level. Among the selected observations, we found pictures of live specimens of species that were previously known only from their shells, such as Megalobulimus pergranulatus (Pilsbry, 1901), bringing to light their appearances in life. Two potentially new species belonging to the genera Plekocheilus Guilding, 1827 and Megalobulimus K. Miller, 1878 were revealed. Additionally, we found records of living individuals of two species that were previously presumed to be possibly extinct, Leiostracus carnavalescus Simone & Salvador, 2016, and Gonyostomus egregius (Pfeiffer, 1845). We take the opportunity to discuss individual records of interest, evaluate the quality of the data and possible improvements, as well the potential and implications of the use of the iNaturalist platform for research in Brazil and other tropical countries. While iNaturalist has its limitations, it holds great potential to help document biodiversity in the tropics.