Anthozoans remain polypoid throughout their lives. Other articles where Anthozoa is discussed: cnidarian: (hydrozoans); Scyphozoa (scyphozoans); Anthozoa (anthozoans); and Cubozoa (cubozoans). Some Sonoran Desert snails from California have been revived after eight years in estivation. Anthozoans, unlike other cnidarians, completely lack a medusa stage; they live exclusively as polyps. Variety and symmetry of body forms, varied coloration, and the sometimes complex life histories of cnidarians fascinate layperson and scientist alike. While anthozoans retain their nematocysts, or stinging cells, and may feed on large prey or particulate food, a number of anthozoans supplement their diet by growing symbiotic algae in their tissues. Introduction Cnidarians are divided into five classes [ 1 ]: Hydrozoa (Usually small, with either or both hydroid and medusoid phases); Anthozoa (Sea Anemones); Scyphozoa (Jellyfish); Staurozoa (Stalked Jellyfish) and Cubozoa (Box Jellyfish).

Theoretically, members of Cnidaria have life cycles that alternate between asexual polyps (the body as a vase shaped form), and sexual, free-swimming forms called medusae (singular medusa; the body in a bell-shaped form). In opisthobranchs and many pulmonates, the life span is about one year, although there are notable exceptions. All cnidarians share several attributes, supporting the theory that they had a single origin. Both gametes are produced by the polyp, which can fuse to give rise to a free-swimming planula larva. Life Cycle In anthozoans, the typical life cycle begins with the development of fertilized eggs into free-swimming larvae known as planula, which in turn transform into polyps that can undergo asexual reproduction to produce new polyps or form colonies. Prosobranchs in general seem to have a much longer life span, with some species of the freshwater Vivipara living 20 years in captivity. The results show the utility of DNA barcoding for matching life-cycle stages as well as for documenting the diversity of this class of organisms. However, members of Anthozoa live only as polyps. Anthozoa: Life History and Ecology. The larva settles on a suitable substratum and develops into a sessile polyp. They can reproduce asexually by budding or fragmentation, or sexually by producing gametes. Anthozoa is a class of marine invertebrates which includes the sea anemones, stony corals and soft corals.Adult anthozoans are almost all attached to the seabed, while their larvae can disperse as part of the plankton.The basic unit of the adult is the polyp; this consists of a cylindrical column topped by a disc with a central mouth surrounded by tentacles.