The fucoxanthin dinophyte lineages (including "Karlodinium" and "Karenia") lost their original red algal derived chloroplast, and replaced it with a new chloroplast derived from a haptophyte endosymbiont. "Karlodinium" and "Karenia" probably took up different heterokontophytes. Because the haptophyte chloroplast has four membranes, tertiary endosymbiosis would be expected to create a six membraned chloroplast, adding the haptophyte's cell membrane and the dinophyte's phagosomal vacuole. However, the haptophyte was heavily reduced, stripped of a few membranes and its nucleus, leaving only its chloroplast (with its original double membrane), and possibly one or two additional membranes around it.