This chapter describes the taxonomy of ciliates. Ciliates can be found in almost every environment; the majority of species, however, are aquatic and occur in marine, brackish, and freshwater habitats. They play a major role in nutrient cycling in the food web; some are also capable of photosynthesis through acquisition of chloroplasts from their prey. The chapter covers their life cycle, generalized morphology, and ecology and distribution. It includes a section that indicates the systematic placement of the taxon described within the tree of life, and lists the key marine representative illustrated in the chapter (usually to genus or family level). This section also provides information on the taxonomic authorities responsible for the classification adopted, recent changes which might have occurred, and lists relevant taxonomic sources.
