A shield-like lateral extension of the thoracic somites, which covers the cephalothorax dorsally and extends from the eyes to the posterior margin of the last thoracic somite. It is cylindrical or angular, and laterally fits snugly against the bases of the pereiopods, enclosing the branchial chamber above the bases of the pereiopods. The carapace may end anterodorsally in a rostrum which is placed between the eyes. The structure, pubescence, sculpturation (grooves and spines) of the carapace are of taxonomic importance.

Alternative form for carapace : dorsal shield.