Catalogue of terrestrial gastropods from Galápagos (except Bulimulidae and Succineidae) with description of a new species of Ambrosiella Odhner (Achatinellidae) (Mollusca: Gastropoda)

Abstract

Excluding the families Bulimulidae and Succineidae, 27 species of land shells were identified in the Galápagos Archipelago (Ecuador), recorded in 14 islands. Many of the species are endemic, belonging to Helicinidae (two species), Achatinellidae (two), Pupillidae (four), Vallonidae (two), Strobilopsidae (one), Pristilomatidae (two), and Euconulidae (three). The most abundant records are found in the human inhabited islands: Santa Cruz, San Cristóbal, Isabela and Floreana. None of the families or genera is exclusive to the archipelago; the only endemic subgenus is Strobilops (Nesostrobilops). The most widespread species is Gastrocopta munita, recorded from 12 islands. Only a few species are recorded as unique to a single island (e.g., Nesopupa (Infranesopupa) galapagensis). A new species of Ambrosiella (Achatinellidae) from Floreana is described: characterized by a parietal lamella in the aperture, this species is related to the Chilean insular fauna. Human inhabited islands host several exotic species of inadvertently introduced micromolluscs and slugs, and one intentional introduction (Lissachatina fulica). Although the introduced species are dominant in anthropogenic altered sectors of the islands, they have also invaded natural areas. New records extend the distribution of almost all terrestrial gastropod species in the Archipelago.