Abstract
The Trochomorphidae is an understudied family of terrestrial pulmonate gastropods. The genera of this family are found throughout Southeast Asia and in western Pacific islands. Belau (Republic of Palau, Oceania) is home to five species of trochomorphids: Videna electra, Videna oleacina, Videna pagodula, Videna pumila, and Liravidena lacerata. While these species were previously described nearly 100 years ago, detailed research on the relationships between these species has yet to be studied. At the same time, these species are facing an extinction crisis due to humans, in the form of habitat loss and the introduction of invasive predators. This research presents the first phylogenetic analyses of the Belau trochomorphids, the first photographs of each of the five species, updated species descriptions, and current geographic range maps. Conservation suggestions for Belau trochomorphids were made based on the results of this research, including the continuation of rat eradication efforts across the archipelago.