RESUMO
Tanytarsini is a large tribe of Chironomidae with at least 11 recorded marine species grouped in three genera. In this study, we performed a phylogenic analysis using molecular data from 13 Tanytarsini genera, including all Japanese marine species in a large tribe of Chironominae, to estimate their phylogenetic positions and evolutionary history. The phylogenetic reconstruction grouped the marine species in two clades. One clade was composed of five marine Tanytarsus and two marine Pontomyia species within a larger clade of Tanytarsus. Pontomyia is considered to have morphologically specialized and adapted to marine environments by rapid evolution, although it formed a clade with Tanytarsus. The only one species of Tanytarsus, T. pelagicus, clustered as a member of the second clade, which was mainly composed by species of the genus Paratanytarsus. Thus, we redescribe T. pelagicus as Paratanytarsus pelagicus.