DNA barcoding supports identification of Malacobdella species (Nemertea: Hoplonemertea).

ALFAYA J.E.F.; BIGATTI, G.; KAJIHARA H.; STRAND M.; SUNBERG P.; MACHORDOM, A.

ZOOLOGICAL STUDIES

ACAD SINICA INST ZOOLOGY

Lugar: Taiwan; Año: 2015 vol. 54 p. 1 - 9

1021-5506

AbstractBackgroundNemerteans of the genus Malacobdella live inside of the mantle cavity of marine bivalves.The genus currently contains only six species, five of which are host-specific and usuallyfound in a single host species, while the sixth species, M. grossa, has a wide host range andhas been found in 27 different bivalve species to date. The main challenge of Malacobdellaspecies identification resides in the similarity of the external morphology between species(terminal sucker, gut undulations number, anus position and gonad colouration), and thus, theillustrations provided in the original descriptions do not allow reliable identification. In thisarticle, we analyse the relationships among three species of Malacobdella: M. arrokeana, M.japonica and M. grossa, adding new data for the M. grossa and reporting the first for M.japonica, analysing 658 base pairs of the mitochondrial cytochrome c oxidase subunit I gene(COI). Based on these analyses, we present and discuss the potential of DNA barcoding forMalacobdella species identification.ResultsSixty-four DNA barcoding fragments of the mitochondrial COI gene from three differentMalacobdella species (M. arrokeana, M. japonica and M. grossa) are analysed (24 of themnewly sequenced for this study, along with four outgroup specimens) and used to delineatespecies. Divergences, measured as uncorrected differences, between the three species wereM. arrokeana-M. grossa 11.73%, M. arrokeana-M. japonica 10.62% and M. grossa-M.japonica 10.97%. The mean intraspecific divergence within the ingroup species showed apatent gap with respect to the interspecific ones: 0.18% for M. arrokeana, 0.13% for M.grossa and 0.02% for M. japonica (ranges from 0 to 0.91%).ConclusionsWe conclude that there is a clear correspondence between the molecular data anddistinguishing morphological characters. Our results thus indicate that some morphologicalcharacters are useful for species identification and support the potential of DNA barcodingfor species identification in a taxonomic group with subtle morphological externaldifferences.