The major subdivision (subclass) of the crustacean class Malacostraca. It comprises three, four, or five Recent superorders: Syncarida, Peracarida, and Eucarida are most commonly included and all that are recognized here. However, some carcinologists still insist on ranking the Hoplocarida among eumalacostracans. Acceptance of a separate superorder, Pancarida for the Thermobaenacea, has not received general support, and thermobaenaceans are commonly now included with peracaridan taxa.