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Crustacea Classes

The Subphylum Crustacea can be further categorized into classes. Crustaceans have two pairs of antennae (usually a short pair and a long pair). None of them have wings.

Malacostraca (Malacostracans)

Order: Decapoda (Decapods): Decapods have ten legs. This group includes crabs, shrimp, and lobsters. There are other animals that may be called “crabs” or “shrimp”, but if they are not part of the decapods, they are not true crabs or true shrimp.

Order: Euphausiacea (Krill): Although they look like shrimp, they are not shrimp. Krill are usually no bigger than 2 inches long.

Order: Isopoda (Isopods): Common names include pill bug, woodlouse, and roly-poly (for its ability to roll up into a ball). Isopods are frequently used in bioactive terrariums, which are reptile or amphibian enclosures that use decomposers (like isopods) to clean up waste.
Another example of an isopod is the Fish Tongue-eating Louse. 

Order: Amphipoda (Amphipods): Their body is flattened sideways, and they have an arched back. Amphipods are different from isopods.

Order: Stomatopoda (The Mantis Shrimp): The Mantis Shrimp is in a group of its own. It is actually not a shrimp.

Maxillopoda (Maxillopods)

The maxillopods include barnacles, copepods, and branchiurans (fish lice).

Branchiopoda (Branchiopods)

The branchiopods include tadpole shrimp (triops), brine shrimp (sea monkeys), fairy shrimp, clam shrimp, and water fleas (daphnia).

The video of an ephemeral pool demonstrates the amazing life cycle of these animals. To quote the video, the animals “hatched on bare, scorched rock after the July 26 thunderstorm, and had only two weeks to grow up, breed, lay their eggs and die.” At the end of the video, the temporary pool dried up. The animals sadly died, but they achieved their goal of laying eggs. The next time it rains, another pool will form, and the eggs will hatch, repeating the cycle.

Ostracoda (Seed Shrimp)

Seed shrimp are microscopic aquatic crustaceans.

Remipedia (Remipedes)

The remipede is a blind predator that lives in underwater caves. It is the only known venomous crustacean.