Flagellates are single-celled protista with one or more flagella, a whip-like organelle often used for propulsion. Originally they were grouped together as the Mastigophora, but the different lines do not appear particularly closely related.
It is quite possible the ancestral eukaryote was a flagellate, and if not they appeared fairly early on. The animals, fungi, and plants are all derived from various lines of flagellates - something reflected in the presence of flagellated cells in most forms, whose ultrastructure is a useful guide to determining relatioships. Flagellate protists include:
- Heterolobosea (amoeboflagellates)
- Euglenozoa (kinetoplastids, euglenids)
- Stramenopiles (golden algae, bicosoecids, etc)
- Green algae
In german flagellate are Geisseltierchen.