The cysts of Dinoflagellés
Dinoflagellés, so known under the name of Dinophycées, appeared there is more than 400 million years. These microseaweeds are established by a big cell, surrounded mostly by a structure membranaire complex understanding a cellulosic thèque trained of two valves separated transversely by a furrow.
Dinoflagellés possesses two flog who allow them to move, but also are, for certain sorts, to capture their prey. Dinoflagellés is bodies phytoplanctoniques marine or brackish, moderate and warm waters.
Half of the current sorts are photosynthetic thanks to their plastes. Others feed on plankton which they capture with their flagellum.
Most of the sorts are asexual and multiply by fission. Some can train cysts which remain still until appearance of favorable conditions.
In paleontology, we can collect the fossil cysts by making react the sample with the only HCl or with HF and by sieving with a nylon sieve of 20 µm.