Search

The family Teredinidae (shipworms) contains 70-plus species of boring bivalves specialized to live in and digest wood. Traditional means of species identification and taxonomy of this group encounter numerous challenges, often compounded by the diverse and dynamic nature of shipworm ecology and distribution. Modern integrative taxonomic methods are shedding new light on this complex group, from delineating cryptic species to resolving phylogenetic relationships within the family. This study reported new sequence data from shipworm species rafted from the western to eastern Pacific Ocean in woody marine debris resulting from the Japanese tsunami of 2011. Eight species of shipworms were found in this debris and tissue from five species was collected. Partial nuclear ribosomal 18S rRNA gene sequences were obtained from Bankia bipennata (Turton, 1819), Bankia carinata (Gray, 1827), Psiloteredo sp., Teredora princesae (Sivickis, 1928), and Teredothyra smithi (Bartsch, 1927). A 658 base pair fragment of COI was successfully sequenced from Psiloteredo sp. and T. princesae specimens from tsunami debris, as well as Psiloteredo megotara (Hanley, 1848) from Europe and Nototeredo norvagica (Spangler, 1792) from Scandinavia. Psiloteredo sp. is very similar morphologically to the North Atlantic Ocean P. megotara; however, these two species are genetically distinct with a 12.8% K2P distance in their COI sequences. The transport of shipworms across the North Pacific Ocean in woody debris generated by a tsunami shows that major geologic events can connect previously isolated geographic areas and provide the opportunity for the establishment of invasive species and subsequent speciation.

The Tohoku tsunami of March 2011 ejected a vast amount of debris into the Pacific Ocean. Wood boring shipworms (Bivalvia: Teredinidae) were either already present in, or settled on, the wooden fraction of this debris, offering a unique opportunity to study shipworm diversity in rafted wood of a known origin and time of ocean entry. Lumber and other wood began appearing on Central Pacific (Hawaiian Islands) and Eastern Pacific beaches in 2013. Eighty pieces of wood Japanese Tsunami Marine Debris (JTMD) consisting of construction beams, trees, milled logs, and wood from vessels or maritime structures were analyzed. Six shipworm species resident in the coastal waters of Japan were found: Bankia bipennata (Turton, 1819), Bankia carinata (Gray, 1827), Teredothyra smithi (Bartsch, 1927), Psiloteredo sp., Lyrodus takanoshimensis (Roch, 1929), and Teredo navalis Linnaeus, 1758. Two pelagic species, Teredora princesae (Sivickis, 1928) and Uperotus clava (Gmelin, 1791), were acquired by JTMD wood in the transoceanic voyage. Several of these wood items were discovered soon after stranding and contained live shipworms. Up to five shipworm species were found in any one wooden object. The present work represents the first study of the diversity and abundance of shipworms transported across an ocean basin in a large woody debris field.