Light and Electron Microscopic Examination of the Parasitic Dinoflagellate Haplozoon

Abstract The parasitic dinoflagellate Haplozoon is found in the intestine of marine polychaetes. It is composed of a chain of cells that hang from the intestinal wall into the lumen, and releases daughter cells from the posterior end of the chain which leave the host and reinfect other polychaetes. Few studies exist in the recent literature regarding Haplozoon and it has not been reported from the Gulf Coast of the United States. This study reports the genus Haplozoon from the maldanid polychaete Axiothella mucosa in St. Andrew Bay, Florida, and examines the structure of the organism by light and electron microscopy. Axiothella mucosa was collected in St. Andrew Bay, Florida and maintained in seawater at the Troy State University campus. Haplozoon spp. was prepared for whole mounts by smearing minced setigers of the worms onto a slide with a drop of seawater.