The freshwater Grapsid crabs of Jamaica

Abstract

Four species of grapsid crabs, endemic to Jamaica, spend the whole of their life cycle in fresh water; an account of their biology is given. Metopulias depressus is confined to the water which collects at the base of large tank bromeliads, and is limited to limestone regions above an elevation of about a 1000 ft. Sesarma bidentatum is common in the upper reaches of most river systems in Jamaica. Sesarma jarvisi is known only from a few specimens; it may be terrestrial in habitat. Sesarma verleyi is one of the few crabs confined to a subterranean existence, and is known to inhabit several cave systems in Jamaica. Evolution by descent from a single invasion of fresh water by marine members of the sub-genus Sesarma is discussed.