''Stylonychia'' 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

Hypotrichia 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 ...

. Species of ''Stylonychia'' are very common in fresh water and soil, and may be found on

filamentous algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular micro ...

, surface films, and among particles of sediment. Like other Hypotrichs, ''St ylonychia'' has

cilia The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projecti ...

grouped into

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 alongside the mouth and

cirri Giovanni Battista Cirri (1 October 1724 – 11 June 1808) was an Italian cellist and composer in the 18th century. Biography Cirri was born in Forlì in the Emilia-Romagna Region of Italy. He had his first musical training with his brother ...

over the body. It is distinguished partly by long cirri at the posterior, usually a cluster of three. The largest can just be seen at a 25x magnification, and the smallest can just be seen at a 450x magnification.

Description

''Stylonychia'' cells are roughly oval in shape, inflexible and flattened from back to front. The organism's cilia are grouped into structures called "cirri," tufts of joined cilia that function together as a unit. The 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 language, Greek roots, describe something in its standard anatomical position. Th ...

surface of the cell can function as legs, enabling the organism to walk along solid substrates, such as submerged algae, leaves or debris. LIke other ciliates of the family Oxytrichidae, ''Stylonychia'' has a prominent group of eighteen large cirri on its ventral surface, arranged into six smaller groups: the frontal, buccal, frontoventral, postoral, pretransverse and transverse cirri. The region around the cell mouth (

cytostome A cytostome (from ''cyto-'', cell and ''stome-'', mouth) or cell mouth is a part of a cell specialized for phagocytosis, usually in the form of a microtubule-supported funnel or groove. Food is directed into the cytostome, and sealed into vacuole ...

) is partially encircled by a series of compound cilia which make up the " adoral zone of membranelles", or AZM. This structure, which resembles the collar and lapel of a

jacket A jacket is a garment for the upper body, usually extending below the hips. A jacket typically has sleeves, and fastens in the front or slightly on the side. A jacket is generally lighter, tighter-fitting, and less insulating than a coat, which ...

, is used mainly to circulate water and brush particles of food into the organism's cell mouth. On the right side of the oral area are two "undulating membranes", delicate scarf-like structures made up of fused cilia. At the posterior of the cell are three long, stiff "caudal cirri", attached to the body at the lower margin of its

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

surface.

Image and video Gallery

File:Stylonychia putrina - 160x - II (13215594964).jpg, ''Stylonychia putrina'' File:Stylonychia.ogv, ''Stylonychia'' eating (vacuole formation) File:Stylonychia growing a second mouth (stomatogenesis prior to division).ogg, ''Stylonychia'' growing a second mouth (stomatogenesis, prior to cell division)

References

External links

Movies of ''Stylonychia'' movementVideo of ''Stylonychia'' creating water currents with its cilia
Ciliate genera Spirotrichea Articles containing video clips {{ciliate-stub