The systematics and ecology of a new genus of isopod (sphaeromatidae) from the west coast sandy beaches of India

Abstract

A new genus and a new species of a psammobiotic, sphaeromatid isopod, Tholozodium ocellatum, is described from the west coast of India (Goa). It is found on fine sediment beaches (Mdo = 2·72-2·47) located in the vicinity of estuaries which receive large inputs of organic matter.

The species is mainly distributed at the upper reaches of the beach and occurs in densities ranging from a few individuals to over 4700 m⁻². The existing evidence indicates that this herbivorous/omnivorous species has a fossorial existence without the occurrence of a free-swimming phase and with little interaction with the rest of the fauna. Moreover T. ocellatum in common with some other platybranch genera does not fit into any of the sub-divisions of this group as proposed by Hansen (1905). This suggests that with more information becoming available an extensive revision of this group of sphaeromatids is needed.