A molecular phylogeny of wood-borers (Teredinidae) from Japanese Tsunami Marine Debris

Abstract

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.