Occurrence and Distribution of Shipworms (Mollusca: Bivalvia: Teredinidae) and Two New Records of Bankia species along the Coast of Hokkaido, Japan

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Shipworms of the family Teredinidae were collected from driftwood along the coastal areas of Hokkaido between October 2020 and November 2021. Identification of species recorded a total of five species pervaded wooden debris: Teredo navalis Linnaeus, 1758, Lyrodus pedicellatus (Quatrefages, 1849), Bankia setacea (Tryon, 1863), Bankia bipennata (Turton, 1819), and Bankia carinata (Gray, 1827), the latter two were warm-water elements and considered a new record of species discovered from the temperate zone of Hokkaido waters. This suggests the possibility that ocean currents and suitable environmental conditions caused the settlement of these teredinids in driftwood along the vast coastal stretches of Hokkaido. Also, B. bipennata and B. carinata have been most likely distributed along the Sea of Japan and brought accidentally by typhoons from the Kuroshio region and Tsushima and Tsugaru currents to Hokkaido, respectively. Moreover, biogeographic patterns within Teredinidae from other coastal areas in the country and elsewhere were examined from the available literature.