Symbiotic Association between Athanas dorsalis (Alpheidae) and Stomopneustes variolaris (Echinoidea) from Visakhapatnam Coast, India

摘要

The alpheid shrimp, Athanas dorsalis (Stimpson, 1865) is reported for the first time at Bay of Bengal (Visakhapatnam, east coast of India). The present study reports a new association between the rock boring intertidal dwelling sea urchin Stomopneustes variolaris (Lamarck, 1816) and the alpheidae, A. dorsalis. These shrimps were found among the spines between ambital region and oral end, preferring more towards oral surface. One to three individuals were found to inhabit sea urchins of diameter in the range of 48 mm to 76 mm. The black colour of the shrimp renders it cryptic by being camouflaged with the similar colour of the spines of the host. Thus the shrimp is protected from the predators. Also the shrimp derives its food from the algal bits nibbled by the host. The host does not seem to have any obvious advantage out of this association. Hence the relationship between the host and the shrimp is commensalism.