What are Dinoflagellates? The term dinoflagellate means “whirling flagella,” and refers to the two long, hair-like strands these organisms use for locomotion. Dinoflagellates may be best known for those that cause the summer “red tides” that can devastate populations of marine life. Fossils of dinoflagellates come in two different forms reflecting their two-stage life cycle: cysts and active stages. The resting-stage cysts are essentially spiny balls, while the active stages are made of many plates in various shapes. Dinoflagellates have been found in rocks as old as the Silurian.
First known fossil occurrence: Silurian.
Last known fossil occurrence: Quaternary. This group has living relatives.
Fossils through time:
Choose a time period to see what life was like: