DNA Barcoding of Primitive Species-Nemertine from Sundarbans Marine Bio-resource

The phylum Nemertea is known as “ribbon worms” or “proboscis worms” or nemertine. Most are very slim, usually, only a few millimetres wide, although a few have relatively short but wide bodies. They are believed to be an ancient order with their origins in the Cambrian period over 500 million years ago. These nemerteans are distributed globally mostly in the temperate tropical region. Nevertheless, this group is mostly neglected and its taxonomy is jumbled with some blurry and incomplete descriptions and thus created perplexity in the identification process. In a case study, the nemertine samples were collected from the Sundarbans delta (one of the largest biodiversity hotspots) and were subjected to DNA Barcoding approach for species level identification. The sequence analysis was done in comparison with the previously characterized species, calculating its genetic distance (Kimura-2-parameter) as well as similarity match with the published sequence. It was found that the samples from the Sundarbans clustered distinctly as a separate clade with respect to other species, which was congruent with the genetic distance. From this study, it was confirmed that the species from this region was novel as compared to other distinguished species, which was nearly impossible with the conventional morphology due to lack of valid diagnostic keys. In this context, DNA taxonomy has proved itself to be a more powerful tool to systematizing taxa in the definite clades, recognition of possible bio-geographic patterns of these species or to uncover possible hidden species.