Redescription of Echinoderes ohtsukai Yamasaki and Kajihara, 2012 and E. kozloffi Higgins, 1977 from the northeastern Pacific coast, including the first report of a potential invasive species of kinorhynch

Although the dispersal ability of kinorhynchs is known to be limited, the distribution of certain kinorhynch species appears to extend over vast geographical areas. Combining molecular phylogenetic data with biogeographical investigations can test this paradox by discerning cryptic species with restricted distributions from species with potentially large geographical distributions. In this paper, we (1) redescribe two species of kinorhynchs (Echinoderes ohtsukai and E. kozloffi) found in the northeastern Pacific Ocean using molecular and morphological data and (2) provide the first evidence for a disjunct geographical distribution in kinorhynchs that is consistent with the introduction of an invasive species. Although we collected E. ohtsukai from the northeastern Pacific Ocean (British Columbia, Canada), this species was originally described from Japan. We demonstrated that specimens of E. ohtsukai collected from Japan and British Columbia have identical DNA sequences for the mitochondrial cytochrome c oxidase subunit 1 (COI) gene. These results are most consistent with a recent introduction of this species into one of the habitats on the opposite side of the Pacific Ocean through human-mediated dispersal.