[2] Members of the order are known as gymnodinioid or gymnodinoid (terms that can also refer to any organism of similar morphology).

They are athecate, or lacking an armored exterior, and as a result are relatively difficult to study because specimens are easily damaged.

Many species are part of the marine plankton and are of interest primarily due to being found in algal blooms.

"[3] Of the families in the order, the Polykrikaceae and Warnowiaceae are well known for possessing exceptionally complex assemblies of organelles, such as nematocysts, trichocysts, and pistons.

The Warnowiaceae uniquely possess an ocelloid, an extremely complex light-sensitive subcellular structure composed of mitochondria and plastids.