What is the Difference Between Lophotrochozoans, Edcysozoans, and Platyzoans?
There are two primary groupings of bilaterian (bilaterally symmetrical) animals; protostomes and deuterostomes. They are also called superphyla, because each contains multiple animal phyla. The deuterostomes tend to be more complex, and include echinoderms, hemichordates, chordates (all vertebrates), and a few smaller phyla. The protostomes contain practically everything else, including arthropods, annelids, flatworms, mollusks, etc. A few small phyla are not classified as either. The primary difference between the two groups is how they develop as embryos: in protostomes, the first opening in the embryo becomes the anus, and in deuterostomes, it becomes the mouth. Most scientists recognize at least three superphyla within protostomes — Lophotrochozoa, Edcysozoa, and Platyzoa. These superphyla were proposed in 1995, 1997, and 1998 respectively, based on molecular and morphological evidence. Lophotrochozoans (“crest-bearing animals”) are united by the presence of a lophophore, a ring o
