A revision of the extant species of Theodoxus (Gastropoda, Neritidae) in Asia, with the description of three new species

Abstract

Asia contains a high species diversity of the freshwater gastropod genusTheodoxus. Recent molecular and morphological reviews of this diversity have uncovered a number of yet undescribed species while suggesting the urgent revision of several others. Moreover, some of these studies have indicated a number of species previously not recorded for this continent. Despite the advancements, a taxonomic revision and an update on the distribution ofTheodoxusspp. in Asia is still pending. Here, we construct the most robust phylogeny ofTheodoxusup to now and review original descriptions, type material, recent taxonomic revisions, compendia, and species lists to provide a comprehensive checklist of all known extant AsianTheodoxusspp. Our checklist also provides descriptions for three recently discovered and yet undescribed species (Theodoxus gururSands & Glöer,sp. nov.,Theodoxus wesselinghiSands & Glöer,sp. nov., andTheodoxus wilkeiSands & Glöer,sp. nov.), as well as shows the need to synonymise several previously described morphospecies. The present revision recognizes 14 extantTheodoxusspp. for Asia. Some of these species are widespread, while others are endemic to just a single location. Based on the revised and new distribution data, we provide updates and new assessments of species conservation statuses.