What are the Major Groups of Cnidarians?
Cnidarians, members of phylum Cnidaria, are among the simplest and most basal animals, splitting off from other phyla even before sponges did, as was discovered by molecular studies in 2008. Cnidarians are among the earliest animal fossils with recognizable affinity to modern groups. The four main cnidarian groups (classes) are Anthozoa (anemones, corals, etc.), Scyphozoa (jellyfish), Staurozoa (stalked jellyfish), Cubozoa (box jellies), Hydrozoa (Obelia, Portuguese Man o’ War, Aequorea, etc.), and Polypodiozoa, which includes a single species, Polypodium hydriforme, a small parasite. Like phylum Ctenophora, cnidarians are diploblastic, meaning their body plan consist of just two germ layers, in contrast to all other animal phyla except sponges. This means that they lack true organs and a coelom (body cavity). Though superficially simple, modern cnidarians are actually genetically sophisticated and biochemically complex. The phylum gets its name from the Greek word for sting. This is b
Cnidarians, members of phylum Cnidaria, are among the simplest and most basal animals, splitting off from other phyla even before sponges did, as was discovered by molecular studies in 2008. Cnidarians are among the earliest animal fossils with recognizable affinity to modern groups. The four main cnidarian groups (classes) are Anthozoa (anemones, corals, etc.), Scyphozoa (jellyfish), Staurozoa (stalked jellyfish), Cubozoa (box jellies), Hydrozoa (Obelia, Portuguese Man o’ War, Aequorea, etc.), and Polypodiozoa, which includes a single species, Polypodium hydriforme, a small parasite.
