New host record of pea crab Arcotheres purpureus (Alcock, 1900) (Crustacea: Decapoda: Pinnotheridae) with first description of male

Background: Arcotheres purpureus, a species of pea crab has been reported from the Red Sea, Maldives and Andaman Sea with no description of the male. According to existing literature the single host for this species is Ostrea. Methods: The specimens examined were obtained from the dredge hauls. Results: In the present study we report Arcotheres purpureus for the first time from the coastal waters of mainland India. The specimens have been observed within the mantle cavity of a venerid bivalve Protapes gallus a new host record for this species. A description of the male specimen is also communicated herein for the first time. Conclusions: Bivalve fisheries is an alternative livelihood option for the fishermen of this region. In this context the manifestation of Arcotheres purpureus, from a commercially viable species of bivalve such as Protapes gallus as well as its incidence in waters of mainland, India is a cause for concern necessitating further investigations.