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
''
''Paramecium'' ( , ; also spelled ''Paramoecium'') is a genus of eukaryotic, unicellular ciliates, commonly studied as a representative of the ciliate group. ''Paramecia'' are widespread in freshwater, brackish, and marine environments and a ...
''. Trichostomatia (trichostomes) are mostly
endosymbiont
An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship.
(The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within ...
s in the digestive tracts of vertebrates. These include the species ''
Balantidium
''Balantidium'' is a genus of ciliates. It contains the parasitic species ''Balantidium coli'', the only known cause of balantidiasis.
History
The first-described species of ''Balantidium'', ''B. entozoon'', was described in 1838 by Ehrenberg as ...
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.
Morphology
In litostomes, the body cilia arise from structures in the
cell cortex called