Euplotes
Introduction '''''Euplotes''''' is a genus of ciliates 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 organisms in the digestive tracts of sea urchins.
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 organelles called "cirri," made up of thick tufts of cilia sparsely distributed on the cell. Strong cirri on the ventral 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 is typically long and narrow, and approximately horseshoe-shaped, C-shaped, or resembling the number 3.
History and Classification C.G. Ehrenberg in 1838|alt=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 WORMSDrawing of ''Euplotes harpa'', a marine speciesFile:Euplotes.webm