First record of Stylostomum ellipse (Dalyell, 1853) (Platyhelminthes, Polycladida) from the Pacific Ocean

• Published in: Check List
• Main Authors: Aoi Tsuyuki, Yuki Oya, Hiroshi Kajihara
• Format: Article in Journal/Newspaper
• Language: English
• Published: Pensoft Publishers 2020
• Subjects: Cosmopolitan species; Euryleptidae; genetic distan; Biology (General); QH301-705.5; Antarctic; The Antarctic; Pacific; South Georgia Island; Antarc*
• Online Access: https://doi.org/10.15560/16.3.773; https://doaj.org/article/29e76e5747de48579f2122ee285030e9

The polyclad flatworm Stylostomum ellipse (Dalyell, 1853) has hitherto been recorded from the Antarctic region, Mediterranean Sea, Patagonian region, Scandinavia, South Africa, and South Georgia Island. In this study, we report S. ellipse for the first time from the Pacific Ocean based on specimens collected in Hokkaido, northern Japan. Our specimens are morphologically identifiable as S. ellipse, but may represent a biologically different species from a population of the Mediterranean Sea. This is because, based on the previous genetic data of other cotylean species, the observed uncorrected p-distance 0.02160 between the two distinct populations in terms of a partial 972 bp region of the 28S rDNA sequence may be great enough to separate the species biologically.