Ciliophora

Article By:

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

Last reviewed:November 2019

DOI:https://doi.org/10.1036/1097-8542.136300

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• Ciliophora, published June 2014:Download PDF Get Adobe Acrobat Reader

A phylum of ciliated protozoans. The members of the phylum Ciliophora (also Ciliata), known commonly as ciliates (Fig. 1), constitute a fairly homogeneous group of highly differentiated, unicellular organisms. They are distinguished principally by a mouth, ciliation, and infraciliature. More than 7500 species have been described, with many more awaiting discovery. Typically, ciliates are larger than most other protozoa, ranging from 10 to 3000 μm (0.0004 to 0.12 in.). Some larger species are visible to the naked eye. The majority of them are free-living forms, found abundantly in a variety of freshwater and saltwater habitats, although a few entire groups live in association with other organisms, generally as harmless ectocommensals or endocommensals. Their principal value to humans is as experimental organisms in a host of investigations concerned with fundamental problems of biology. In particular, ciliates belonging to the genus Paramecium are important model organisms. Although the exact classification scheme for the Ciliophora is often debated, some notable constituents are the holotrichs, gymnostomes, peritrichs, suctorians, heterotrichs, hypotrichs, tintinnids, and odontostomes, among others. See also: Apostomatida; Astomatida; Chonotrichida; Cilia and flagella; Entodiniomorphida; Gymnostomatida; Heterotrichida; Holotrichia; Hymenostomatida; Hypotrichida; Peritrichia; Protozoa; Suctoria; Tintinnida

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