Hoplocarida is a subclass of crustaceans. The only extant members are the mantis shrimp, but two other orders existed in the Palaeozoic: Aeschronectida and Palaeostomatopoda.

Eumalacostraca is a subclass of crustaceans, containing almost all living malacostracans, or about 40,000 described species. The remaining subclasses of crustaceans that are not in Eumalacostraca are