Ventrata is an infraphylum of

ciliates 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 different ...

inside the subphylum

Intramacronucleata Intramacronucleata is a subphylum of ciliates. The group is characterized by the manner in which division of the macronucleus is accomplished during binary fission of the cell. In ciliates of this subphylum, division of the macronucleus is ach ...

that unites the classes

Phyllopharyngea The Phyllopharyngea are a class of ciliates, some of which are extremely specialized. Motile cells typically have cilia restricted to the ventral surface, or some part thereof, arising from monokinetids with a characteristic ultrastructure. In ...

Colpodea The Colpodea are a class of ciliates, of about 200 species common in freshwater and soil habitats. The body cilia are typically uniform, and are supported by dikinetids of characteristic structure, with cilia on both kinetosomes. The mouth may ...

Nassophorea The Nassophorea are a class of ciliates. Members are free-living, usually in freshwater but also in marine and soil environments. The mouth is anterior ventral and leads to a curved cytopharynx supported by a prominent palisade of rods or ''ne ...

Prostomatea Prostomatea is a class of ciliates. It includes the genera '' Coleps'' and '' Pelagothrix''. References Further reading Intramacronucleata Ciliate classes {{ciliate-stub ...

Plagiopylea The plagiopylids are a small order of ciliates, including a few forms common in anaerobic habitats. The body cilia are dense, and arise from monokinetids with an entirely unique ultrastructure; one or two rows of dikinetids run into the oral ca ...

and

Oligohymenophorea The Oligohymenophorea are a large class of ciliates. There is typically a ventral groove containing the mouth and distinct oral cilia, separate from those of the body. These include a paroral membrane to the right of the mouth and membranelles, ...

. It is equivalent to the clade CONthreeP or Conthreep recovered by phylogenetic analyses.

Description

Members of this

taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...

are characterized by having, ancestrally, a ventral

cytopharynx 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 ...

, as the name suggests.

Phylogeny

The

monophyly In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gr ...

of CONthreeP is well supported, being placed as sister to

Protocruziea Protocruziea is a class of ciliates in the subphylum Intramacronucleata Intramacronucleata is a subphylum of ciliates. The group is characterized by the manner in which division of the macronucleus is accomplished during binary fission of t ...

. The order Discotrichida, belonging to class

, has been recovered as the earliest branch of the clade.

References

{{Taxonbar, from=Q25360752 Intramacronucleata