Which animals belong to the crustacean group?

Crustaceans are a diverse subphylum of the phylum Arthropoda, comprising approximately 45,000 described species. While they are primarily aquatic, inhabiting environments ranging from deep oceanic trenches to freshwater lakes, some species have adapted to terrestrial life.1234

The group includes a wide variety of forms, ranging from familiar shellfish to minute planktonic organisms. Notable members include:14

• Decapods: This order includes crabs, lobsters, shrimp, and crayfish.25
• Barnacles: Members of the infraclass Cirripedia, such as acorn barnacles and goose barnacles, are sedentary crustaceans.67
• Isopods: This group includes wood lice (pill bugs and sow bugs), which are among the most terrestrial crustaceans.32
• Other forms: The subphylum also encompasses copepods, amphipods, water fleas, mantis shrimp, and fairy shrimp, among many others.2

Crustaceans are distinguished from other arthropods by having two pairs of antennae and specialized appendages near the mouth that function as jaws, though there is significant structural variation across the group.15