A new species of chionelasmatid sessile vent barnacle, Eochionelasmus coreana sp. nov., is described and illustrated on the basis of specimens collected from the Solitaire hydrothermal vent field in the Central Indian Ridge of the Indian Ocean. This new species is morphologically very similar to E. ohtai, the type species of the genus Eochionelasmus. However, it differs from E. ohtai in its distribution, the status of the notch on the maxillule, and the positions of rl1 and cl1 on whorls of the imbricating plates. In addition, a molecular phylogenetic tree indicated that the chionelasmatid Eochionelasmus was closely related to the waikalasmatid Waikalasma with high supporting values rather than the other chionelasmatid Chionelasmus. The new species is not only the first record of a sessile vent barnacle from outside of the Pacific Ocean, but is also the first sessile barnacle from the Indian Ocean.
