Plasmodiophoridae

Circumscription: Mostly parasitic, some phagotrophic consumers of cell contents of plants and oomycetes. Some with a highly unusual extrusome (stachel) used for penetrating food cells. Feeding cell may or may not be plasmodial, giving rise to multiple zoospores with two or four flagella; flagella without hairs, hence excluded from Oomycetes (stramenopiles) with which they are normally allied. With long-lived cysts with chitin in their walls. Ultrastructural identity: Form of mitochondrial cristae is ambiguous, appearing either flat or sacculate µmolecular evidence suggests plasmodiophorids are allied to tubulocristate eukaryotes). With a distinctive cruciate appearance of nucleus during mitosis of vegetative cells. Flagellar basal bodies long. May have complex extrusomes. Synapomorphy: Eukaryotes with cruciate mitotic profiles in dividing vegetative cells.