''Euplotes'' is a genus of

ciliate The ciliates are a group of alveolates 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 differen ...

s in the subclass Euplotia. Species are widely distributed in marine and freshwater environments, as well as soil and moss. Most members of the genus are free-living, but two species have been recorded as

commensal Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ...

organisms in the digestive tracts of sea urchins.

Description

''Euplotes'' cells are inflexible,

dorsoventrally Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

flattened, and roughly ovoid, with a very large oral region (peristome) bordered on the left by a long "adoral zone of

membranelle Membranelles (also membranellae) are structures found around the mouth, or cytostome, in ciliates. They are typically arranged in series, to form an "adoral zone of membranelles," or AZM, on the left side of the buccal cavity (peristome). The membra ...

s" (AZM). Like other

spirotrich The spirotrichs are a large and diverse group of ciliate protozoa. They typically have prominent oral cilia in the form of a series of polykinetids, called the adoral zone of membranelles, beginning anterior to the oral cavity and running down ...

ciliates, ''Euplotes'' move and feed with the help of compound ciliary organelles called "cirri," made up of thick tufts of cilia sparsely distributed on the cell. Strong cirri on the

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

surface of the cell enable ''Euplotes'' to walk or crawl on submerged detritus and vegetation. All species of ''Euplotes'' have a group of stiff bristles ( caudal cirri), which protrude from the posterior of the cell. The number of caudal cirri varies, even within a species, but it is most common for ''Euplotes'' to have 4 or 5. The

macronucleus A macronucleus (formerly also meganucleus) is the larger type of nucleus in ciliates. Macronuclei are polyploid and undergo direct division without mitosis. It controls the non-reproductive cell functions, such as metabolism. During conjugation, ...

is typically long and narrow, and approximately horseshoe-shaped, C-shaped, or resembling the number 3.

History and Classification

Species of ''Euplotes'' were first recorded in 1773 by the Danish naturalist O.F. Müller, who placed them in the genus ''Trichoda''. In 1830,German microscopist C.G. Ehrenberg created the genus ''Euplotes''. By 1975, over 80 species and varieties had been described and assigned to ''Euplotes''. In older classification schemes, ''Euplotes'' is usually placed among

hypotrich 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 ...

s, either in the order Hypotrichida, the subclass Hypotrichia or the class Hypotrichea. In current classification, ''Euplotes'' is placed apart from the other traditional hypotrichs, in the subclass Euplotia.

References

''Euplotes''
at WORMS Euplotes harpa - Alfred Kahl

File:Euplotes.webm {{Taxonbar, from=Q10278244 Hypotrichea Ciliate genera Taxa named by Christian Gottfried Ehrenberg