The plagiopylids are a small order of ciliates, including a few forms common in anaerobic habitats.
The peritrichs are a large and distinctive group of ciliates.
The Litostomatea are a class of ciliates. The group consists of three subclasses: Haptoria, Trichostomatia and Rhynchostomatia. Haptoria includes mostly carnivorous forms such as Didinium, a species of which preys primarily on the ciliate Paramecium. Trichostomatia (trichostomes) are mostly endosymbionts in the digestive tracts of vertebrates. These include the species Balantidium coli, which is the only ciliate parasitic in humans. The group Rhynchostomatia includes two free-living orders previously included among the Haptoria, but now known to be genetically distinct from them, the Dileptida and the Tracheliida.
The hypotrichs are a group of ciliated protozoa, common in fresh water, salt water, soil and moss. Hypotrichs possess compound ciliary organelles called "cirri," which are made up of thick tufts of cilia, sparsely distributed on the ventral surface of the cell. The multiple fused cilia which form a cirrus function together as a unit, enabling the organism to crawl along solid substrates such as submerged debris or sediments. Hypotrichs typically possess a large oral aperture, bordered on one side by a wreath or collar of membranelles, forming an "adoral zone of membranelles," or AZM.
Stentor, sometimes called trumpet animalcules, are a genus of filter-feeding, heterotrophic ciliates, representative of the heterotrichs. They are usually horn-shaped, and reach lengths of two millimeters; as such, they are among the biggest known extant unicellular organisms. They reproduce asexually through binary fission.
Vorticella is a genus of bell-shaped ciliates that have stalks to attach themselves to substrates. The stalks have contractile myonemes, allowing them to pull the cell body against substrates. The formation of the stalk happens after the free-swimming stage.
Didinium is a genus of unicellular ciliates with at least ten accepted species. All are free-living carnivores. Most are found in fresh and brackish water, but three marine species are known. Their diet consists largely of Paramecium, although they will also attack and consume other ciliates. Some species, such as D. gargantua, also feed on non-ciliate protists, including dinoflagellates, cryptomonads, and green algae.
Spirostomum is a genus of free-living ciliate protists, belonging to the class Heterotrichea. Species of Spirostomum are found in both salt and fresh water. All are elongated, flexible and highly contractile. Although unicellular, members of some species can grow as long as 4 mm (0.16 in).
Plagiopyla is a genus of ciliates. It includes nine species:
Karyorelictea is a class of ciliates in the subphylum Postciliodesmatophora. Most species are members of the microbenthos community, that is, microscopic organisms found in the marine interstitial habitat, though one genus, Loxodes, is found in freshwater.
Prostomatea is a class of ciliates. It includes the genera Coleps and Pelagothrix.
The ciliates are a group of protozoans characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different undulating pattern than flagella. Cilia occur in all members of the group and are variously used in swimming, crawling, attachment, feeding, and sensation.
Epixenosomes, also known as Candidatus Epixenosoma are a genus of bacteria in the phylum Verrucomicrobia that form a symbiosis with marine ciliates of the genus Euplotidium, where they help to defend their ciliate hosts against predators. It is a monospecific genus, containing only the species Ca. Epixenosoma ejectans.
Climacostomum is a genus of unicellular ciliates, belonging to the class Heterotrichea.
Trichodinidae is a family of ciliates of the order Mobilida, class Oligohymenophorea. Members of the family are ectoparasites of a wide variety of aquatic organisms, including fish, amphibians, hydrozoans, molluscs and crustaceans.
Loxodidae is a family of karyorelict ciliates.
Armophorea is a class of ciliates in the subphylum Intramacronucleata. . It was first resolved in 2004 and comprises three orders: Metopida, Clevelandellida, and Armophorida. Previously members of this class were thought to be heterotrichs because of similarities in morphology, most notably a characteristic dense arrangement of cilia surrounding their oral structures. However, the development of genetic tools and subsequent incorporation of DNA sequence information has led to major revisions in the evolutionary relationships of many protists, including ciliates. Metopids, clevelandellids, and armophorids were grouped into this class based on similarities in their small subunit rRNA sequences, making them one of two so-called "riboclasses" of ciliates, however, recent analyses suggest that Armophorida may not be related to the other two orders.
Wilbertomorphidae is a family of karyorelictean ciliates. The family is monotypic, because it contains a single genus Wilbertomorpha with a single known species, Wilbertomorpha colpoda.
Licnophora is a genus of ciliates in the family Licnophoridae. They typically have an hourglass-like shape and live as ectocommensals on marine animals.
Miamiensis avidus is a species of unicellular marine eukaryote that is a parasite of many different types of fish. It is one of several organisms known to cause the fish disease scuticociliatosis and is considered an economically significant pathogen of farmed fish. M. avidus is believed to be the cause of a 2017 die-off of fish and sharks in the San Francisco Bay.
