A New Species of Prosadenoporus (Nemertea: Eumonostilifera) from the North-East Coast of the Bay of Bengal, India

A semi-terrestrial eumonostiliferous hoplonemertean species was discovered on the northeastern coast of the Bay of Bengal, India. Histological studies confirmed its affiliation with the genus <i>Prosadenoporus</i> Bürger, 1890. In this paper, it is described as a new species, <i>Prosadenoporus indicus</i> sp. nov. This species is distinguished from its congeners by a distinct black patch on the antero-dorsal surface of the head, a large body size, 16-18 proboscis nerves, a large frontal organ, the presence of neurochord cell, and exclusively circular muscles surrounding the rhynchodeum. A maximum-likelihood analysis of 658-bp cytochrome <i>c</i> oxidase subunit I (COI) gene sequences, including data from this species and five congeners available in public databases, supported the generic placement of the new species. The new species exhibited 10.3-11.1% uncorrected <i>p</i>-distance differences in 658-bp COI sequences compared to its congeners.