''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 flagellum, eukaryotic flagella, but are in general shorter and present in much larger numbers, with a ...

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 f ...

organisms in the digestive tracts of

sea urchin Sea urchins or urchins () are echinoderms in the class (biology), class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body cove ...

Description

''Euplotes'' cells are inflexible, dorsoventrally flattened, and roughly ovoid, with a very large oral region (peristome) bordered on the left by a long "adoral zone of membranelles" (AZM). Like other spirotrich ciliates, ''Euplotes'' move and feed with the help of compound ciliary

organelle In cell biology, an organelle is a specialized subunit, usually within a cell (biology), cell, that has a specific function. The name ''organelle'' comes from the idea that these structures are parts of cells, as Organ (anatomy), organs are to th ...

s called "cirri," made up of thick tufts of

cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...

sparsely distributed on the cell. Strong cirri on the

ventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. 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 Metabolism (, ...

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 hypotrichs, 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 {{Authority control Hypotrichea Ciliate genera Taxa named by Christian Gottfried Ehrenberg