Lophogastrids: Lophogastrida

Physical characteristics: The giant red mysid is the largest crustacean that lives in open water. It measures up to 13.78 inches (350 millimeters) in length. The carapace has a very long, beaklike projection that extends almost to the end of the first pair of antennae, or antennules. The flaplike exopods of the second pair of antennae are long with sharply pointed tips. The back of the carapace is extended as a spine that reaches back to the second abdominal segment. The carapace is folded inward underneath the body to form a partially enclosed gill chamber.

Geographic range: Giant red mysids live in deep waters below the tropical and subtropical waters of the Atlantic, Pacific, and Indian oceans.

Habitat: They live in deep, open waters, usually at depths of 1,300 to 4,920 feet (396 to 1,500 meters).

Diet: Giant red mysids eat large particles filtered from the seawater, as well as small dead organisms found in the water.

The giant red mysid is the largest crustacean that lives in open water. It measures up to 13.78 inches (350 millimeters) in length. (Illustration by John Megahan. Reproduced by permission.)

Behavior and reproduction: Little is known about the behavior of this species. Gnathophausia ingens has a very long period of larval development that is estimated to be about 530 days. Adult females probably have more than one brood and live for almost 3000 days. From hatching to adult, an individual giant red mysid molts 13 times.

Giant red mysids and people: This species is probably eaten by larger fishes that are fished commercially and sold as human food.

Conservation status: Giant red mysids are not considered endangered or threatened. ∎