Tintinnida

Article By:

Corliss, John O. Department of Zoology, University of Maryland, College Park, Maryland.

Jones, Daniel J. Department of Earth Sciences, California State College, Bakersfield, California.

Last reviewed:January 2021

DOI:https://doi.org/10.1036/1097-8542.698400

An order of the Spirotrichia whose members are conical or trumpet-shaped pelagic forms bearing shells (loricae). These protozoa are planktonic ciliates and are especially abundant in oceans, notably the Pacific. The lorica is composed of a resistant organic compound in which various foreign mineral grains are embedded; its shape may range from trumpet- or bell-form to cylindrical or subspherical, and its size from 50 to 200 micrometers. The exact structure, often quite elaborate, and the dimensions of the lorica are so recognizably different among the hundreds of known genera that the taxonomic arrangement of forms within the order has been based solely on characteristics and properties of this secreted “house.” The adoral zone of membranelles (Fig. 1) is prominent, while the other ciliature is greatly reduced.

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