Crustacea

 Crustacean diversity of Andaman and Nicobar Islands is well studied during 20^th century by many researchers. Coral reefs inhabit several commonly important crustacean fauna. Heller (1865) revealed 14 species of hermit crabs from Nicobar Islands. Alcock (1905) further revealed 14 species and 5 new varieties/species of hermit crabs. Reddy and Ramakrishna (1972) found the occurrence of 20 species followed by Tikader et.al. (1986) reported 37 species lead to a total of 40 species of hermit crabs from Andaman and Nicobar Islands.

 Species composition of brachyuran crabs of A&N Islands has been consolidated as 220 species through the reports of Sakai (1976), Kathirvel (1983), and Tikader et.al. (1986). A total of 162 species of prawn found in coral reef environment of these Islands are published by Silas et.al. (1983) and Tikader et.al. (1986). Apart from that 6 species of lobsters occurred in these Islands (Shanmugham and Kathirvel, 1983)

Ajmal Khan (2002) compiled the list on crustacean fauna from these Islands and it depicts 837 species of crustaceans.

Crustaceans (Crustacea) form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. Most crustaceans are free-living aquatic animals, but some are terrestrial (e.g. woodlice), some are parasitic (e.g. fish lice, tongue worms) and some are sessile (e.g. barnacles). 

The group has an extensive fossil record, reaching back to the Cambrian, and includes living fossils such as Triops cancriformis, which has existed apparently unchanged since the Triassic period. More than 10 million tons of crustaceans are produced by fishery or farming for human consumption, the majority of it being shrimps and prawns. Krill and copepods are not as widely fished, but may be the animals with the greatest biomass on the planet, and form a vital part of the food chain. The scientific study of crustaceans is known as carcinology (alternatively, malacostracology, crustaceology or crustalogy), and a scientist who works in carcinology is a carcinologist (Source: Wikipedia)