Choreotrich

The choreotrichs are a group of small, marine ciliates. Their name reflects the impresion that they appear to dance ('choreo' as in choreography). The group includes the tintinnids, which produce species-specific loricae (shells), and are important because these may be preserved as microfossils. They became common during the Jurassic period, but are first known from as early as the Ordovician, and are important as the only notable record of early ciliates. Often they have been included among the oligotrichs. Tintinnids seem to be an excessively specious group as over 400 living species have been described, based on characteristics of the lorica or shell.

Choreotrichs (including tintinnids) are part of the microzooplankton. Generally small (20 - 200 micrometres in size) organisms found in the plankton. They feed on small algae and serve as prey for larger organisms in the plankton such as copepods and larval fish.