<P> The earliest stages of dinoflagellate evolution appear to be dominated by parasitic lineages, such as perkinsids and syndinians (e.g. Amoebophrya and Hematodinium). </P> <P> All dinoflagellates contain red algal plastids or remnant (nonphotosynthetic) organelles of red algal origin . The parasitic dinoflagellate Hematodinium however lacks a plastid entirely . </P> <P> Dinoflagellate evolution has been summarized into five principal organizational types: prorocentroid, dinophysoid, gonyaulacoid, peridinioid, and gymnodinoid . The transitions of marine species into fresh water have been infrequent events during the diversification of dinoflagellates and in most cases have not occurred recently, possibly as late as the Cretaceous . </P> <P> Recently, the "living fossil" Dapsilidinium pastielsii was found inhabiting the Indo - Pacific Warm Pool, which served as a refuge for thermophilic dinoflagellates . </P>

Blue green algae which live in protozoans are called