''Dileptus'' is a genus of

unicellular A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Organisms fall into two general categories: prokaryotic organisms and ...

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 class

Litostomatea 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 ''P ...

. Species of ''Dileptus'' occur in fresh and salt water, as well as mosses and soils. Most are aggressive predators equipped with long, mobile proboscides lined with toxic

extrusomes Extrusomes are membrane-bound structures in some eukaryotes which, under certain conditions, discharge their contents outside the cell. There are a variety of different types, probably not homologous, and serving various functions. Notable extru ...

, with which they stun smaller organisms before consuming them. 13 species and subspecies of ''Dileptus'' are currently recognized.Vďačný, Peter, and Wilhelm Foissner. Monograph of the dileptids (Protista, Ciliophora, Rhynchostomatia). Land Oberösterreich, Biologiezentrum/Oberösterreichische Landesmuseen, 2012 ''Dileptus'' species have served as

model organism A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workin ...

s, used in the study of ciliary patterns, ontogenesis,

conjugation Conjugation or conjugate may refer to: Linguistics * Grammatical conjugation, the modification of a verb from its basic form * Emotive conjugation or Russell's conjugation, the use of loaded language Mathematics * Complex conjugation, the chang ...

and food acquisition.

Appearance and characteristics

''Dileptus'' bodies are typically narrow or cylindrical, and have a

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, t ...

made up of more than a hundred scattered nodules. During

cell division Cell division is the process by which a parent cell (biology), cell divides into two daughter cells. Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome(s) before dividing. In eukar ...

, these nodules divide individually. At the front end of the cell is a mobile proboscis. The

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 at the base of this organ and is well fortified with stiff microtubular rods (nematodesmata). The surface of the cell is uniformly covered with cilia arranged in longitudinal rows. The body may taper at the back end, forming something like a tail. Multiple

contractile vacuole A contractile vacuole (CV) is a sub-cellular structure (organelle) involved in osmoregulation. It is found predominantly in protists and in unicellular algae. It was previously known as pulsatile or pulsating vacuole. Overview The contractile va ...

s lie in a row along the dorsal surface. Most ''Dileptus'' are colourless, but two nominal species carry

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

green algae The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

in their

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

History and Classification

Dileptus margaritifer from Ehrenberg, 1838

A species of ''Dileptus'' was described by

C. G. Ehrenberg Christian Gottfried Ehrenberg (19 April 1795 – 27 June 1876) was a German Natural history, naturalist, zoologist, comparative anatomist, geologist, and microscopy, microscopist. Ehrenberg was an Evangelicalism, evangelist and was considered to ...

in 1833, under the name ''Amphileptus margaritifer''. Eight years later,

Félix Dujardin Félix Dujardin (5 April 1801 – 8 April 1860) was a French biologist born in Tours. He is remembered for his research on protozoans and other invertebrates. Biography In 1840 he was appointed professor of geology and mineralogy at the Univer ...

created the genus ''Dileptus'' and moved Ehrenberg's ''A. margaritifer'' to it, along with ''Dileptus anser'' Müller 1773 (now classified in '' Pseudomonilicaryon'') and ''Dileptus folium'' (now ''Litonotus cygnus''). Over the next century, many new species were described. By 1963, when Jean Dragesco published the first detailed account of the genus, it included about 50 species. In a comprehensive taxonomic study published in 2012, Peter Vďačný and Wilhelm Foissner restricted the genus ''Dileptus'' to dileptids "having more than 50 dispersed macronuclear nodules that divide individually," which left only ten nominal species within the group. Many traditionally recognized members of ''Dileptus'', including the well-known species ''

Dileptus anser ''Pseudomonilicaryon anser'' is a species of unicellular ciliates in the family Dileptidae, also known under the names ''Dileptus anser'' and ''Dileptus cygnus''. The species is common in fresh water ponds, stagnant pools, mosses and soils. Fo ...

'', have been moved to other genera, such as '' Pseudomonilicaryon'' and '' Rimaleptus''.

Species of Dileptus

* ''

Dileptus anatinus ''Dileptus'' is a genus of unicellular ciliates in the class Litostomatea. Species of ''Dileptus'' occur in fresh and salt water, as well as mosses and soils. Most are aggressive predators equipped with long, mobile proboscides lined with toxic ...

'' Golińska, 1971 * '' Dileptus beersi'' Jones, 1956 * '' Dileptus costaricanus'' Foissner, 1995 * '' Dileptus dubius'' Vuxanovici, 1959 * ''

Dileptus estuarinus ''Dileptus'' is a genus of unicellular ciliates in the class Litostomatea. Species of ''Dileptus'' occur in fresh and salt water, as well as mosses and soils. Most are aggressive predators equipped with long, mobile proboscides lined with toxic ...

'' Dragesco, 1960 * ''

Dileptus jonesi ''Dileptus'' is a genus of unicellular ciliates in the class Litostomatea. Species of ''Dileptus'' occur in fresh and salt water, as well as mosses and soils. Most are aggressive predators equipped with long, mobile proboscides lined with toxic ...

'' Dragesco, 1963 * '' Dileptus margaritifer'' (Ehrenberg, 1833) * ''

Dileptus multinucleatus ''Dileptus'' is a genus of unicellular ciliates in the class Litostomatea. Species of ''Dileptus'' occur in fresh and salt water, as well as mosses and soils. Most are aggressive predators equipped with long, mobile proboscides lined with toxic ...

'' Vuxanovici, 1959 * ''

Dileptus sphagnicola ''Dileptus'' is a genus of unicellular ciliates in the class Litostomatea. Species of ''Dileptus'' occur in fresh and salt water, as well as mosses and soils. Most are aggressive predators equipped with long, mobile proboscides lined with toxic ...

'' Vdacny & Foissner, 2011 * ''

Dileptus viridis ''Dileptus'' is a genus of unicellular ciliates in the class Litostomatea. Species of ''Dileptus'' occur in fresh and salt water, as well as mosses and soils. Most are aggressive predators equipped with long, mobile proboscides lined with toxic ...

'' (Ehrenberg, 1833) Foissner, 1987

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References

{{Taxonbar, from=Q5276756 Litostomatea Ciliate genera Articles containing video clips