RESUMEN
Ascidians are ecologically important components of marine ecosystems, yet the taxonomy and diversity of ascidians remain largely unexplored. Only <60% of reported ascidian species in India have been taxonomically described and identified and the rest of the species remain unidentified due to uncertainty in the morphology-based identification. We explored the usefulness of CO1 gene sequences for molecular level identification and mtDNA data in assessing phylogenetic relationships of 15 ascidian species. The mean sequence divergences within and among the species fell into the mean divergence ranges found in ascidian group. Species that are most similar grouped together formed a cluster. Clusters of species in a clade indicate that the species are closely related. Species that are highly divergent formed a separate branch. This study has concluded that the CO1 gene sequence is an effective tool to ascertain the molecular taxonomical studies on ascidians.