Author: Jan Scholten
English: True jellyfish; True jellies.
Name Scyphozoa comes from the Greek word skyphos denoting a kind of drinking cup and alluding to the cup shape of the organism.
Clades: Cnidaria; Radiata; Animals.
Genera: 2500 species.
Habitat: throughout the world's oceans, from the surface to great depths; no Scyphozoa occur in freshwater or on land.
Scyphozoa are exclusively marine animals. Most Scyphozoa have two life-history phases, including the planktonic medusa or jellyfish form, which is most evident in the warm summer months, and an inconspicuous, but longer-lived, bottom-dwelling polyp, which seasonally gives rise to new medusae. Most of the large, often colorful, and conspicuous jellyfish found in coastal waters throughout the world are Scyphozoa. They typically range from 2 to 40 cm in diameter, but the largest species, Cyanea capillata can reach 2 metres.
Food: they feed on a variety of crustaceans and fish, which they capture using stinging cells called nematocysts. The nematocysts are located throughout the tentacles that radiate downward from the edge of the umbrella dome, and also cover the four or eight oral arms that hang down from the central mouth. Some species, however, are instead filter feeders, using their tentacles to strain plankton from the water.