A carapace is the top part of an exoskeleton or shell in a number of animal groups.
A carapace is another feature of zooplankton in the phylum Crustacea. Ostracods, Cladocera, and isopods are among them; however, isopods only have a developed "cephalic shield" carapace covering their head.
In crustaceans, the carapace serves as a covering to protect the cephalothorax, which is the combined head and thorax, as opposed to the abdomen behind it. The projection that extends forward past the eyes is referred to as a rostrum. The degree of calcification in the carapace varies amongst crustaceans.