An Account of New Records of Reef Associated Crabs of Andaman and Nicobar Islands

The Andaman and Nicobar Islands is located in Bay of Bengal with an area of 8269 km². Andaman and Nicobar Islands comprised of 572 islands spread in a linear distance of nearly 800 kms. These undulating islands are covered with dense forests and an endless variety of exotic flora and fauna between Burma and Indonesia. Andaman and Nicobar Islands are recently recognized as a world-class eco-tourist destination to discover the underwater treasures of marine life. Malacostraca includes most of the large and familiar crustaceans such as crabs, shrimps, lobsters, crayfish, isopods, amphipods and others. Primitively the trunk of malacostraca consists of 15 segments, eight in the thorax and seven in the abdomen but in most recent species the abdomen has only six segments. Decapoda, the largest and most familiar crustaceans with 10,000 species of crabs, shrimps, crayfishes, lobsters, and their relatives. Like the shrimps and lobsters, crabs belong to the order Decapoda (=“ten-legged”, referring to the 10 thoracic appendages normally present in these crustaceans). Crabs can be classified into 2 main groups, brachyuran crabs (infraorder Brachyura) and anomuran crabs (infraorder Anomura). Most species of Brachyura, or true crabs, can easily be separated from the so-called “false crabs” belonging to the infraorder Anomura by having 4 pairs of well-developed walking legs. Brachyuran crabs are bioenergetically vital faunal component of the mangrove ecosystem while decapod crustaceans are dominant in coral habitat.