A new host record of pea crab, Arcotheres placunae (Hornell & Southwell, 1909) (Brachyura: Pinnotheridae), in Placuna quadrangula (Philipsson, 1788) (Bivalvia: Placunidae), from the southeastern coast of India

Abstract

Previously, the pea crab Arcotheres placunae (Hornell & Southwell, 1909) was only recorded from the known host bivalve species, Placuna placenta (Linnaeus, 1758). This study presents the first report on the host association between A. placunae and Placuna quadrangula (Philipsson, 1788) based on specimens found in the Vellar estuary, southeastern coast of India. During regular fishing survey along the Vellar estuary, observed a single male and female specimen of A. placunae in the mantle cavity of a live windowpane oyster, P. quadrangula. The association observed here remarks that the pea crab has a commensal relationship with the host, P. quadrangula. The present study provides the details of morphological features and association of new host of the species herein.