Ventrifilosa () is a highly diverse group of

phagotrophic Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is c ...

protist A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the exc ...

s that

glide Glide may refer to: * Gliding flight, to fly without thrust Computing *Glide API, a 3D graphics interface *Glide OS, a web desktop *Glide (software), an instant video messenger *Glide, a molecular docking software by Schrödinger (company), Schr� ...

through their

flagella A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...

and emit filose

pseudopods A pseudopod or pseudopodium (plural: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filament ...

from their

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 ...

side for feeding. Because of their mixture of

amoeba An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of Cell (biology), cell or unicellular organism with the ability to alter its shape, primarily by extending and ret ...

and

flagellate A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their ...

characteristics, they are amoeboflagellates. Members of this group are the

Imbricatea Imbricatea is a class of Rhizaria characterised by silica scales. It is sometimes described as "Imbricatea/Silicofilosea", due to the similarity of those two groupings. Imbricatea is divided into the orders Euglyphida and Thaumatomonadida Thau ...

Sarcomonadea The sarcomonads () or class Sarcomonadea are a group of amoeboid biciliate protists in the phylum Cercozoa. They are characterized by a propensity to move through gliding on their posterior cilium or through filopodia, a lack of scales or ext ...

and

Thecofilosea Thecofilosea is a class of Cercozoa. References Cercozoa classes {{Cercozoa-stub ...

Morphology

Protists in the group Ventrifilosa ancestrally have a rigid extracellular

theca In biology, a theca (plural thecae) is a sheath or a covering. Botany In botany, the theca is related to plant's flower anatomy. The theca of an angiosperm consists of a pair of microsporangia that are adjacent to each other and share a commo ...

on the

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 ...

side, and emit non-granular filose

pseudopod A pseudopod or pseudopodium (plural: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filamen ...

s from a

aperture. This aperture is called "cleft" when belonging to an amoeboflagellate, or "astropyle" when belonging to a

phaeodaria Phaeodarea, or Phaeodaria, is a group of amoeboid cercozoan organisms. They are traditionally considered radiolarians, but in molecular trees do not appear to be close relatives of the other groups, and are instead placed among the Cercozoa. They ...

n. The group includes descendants that have lost or modified some of these characteristics. For example, some have lost their pseudopods (such as the spongomonads and '' Ebria''), some have lost their

(such as '' Pseudopirsonia''), and some have acquired axopodia (in

Phaeodaria Phaeodarea, or Phaeodaria, is a group of amoeboid cercozoan organisms. They are traditionally considered radiolarians, but in molecular trees do not appear to be close relatives of the other groups, and are instead placed among the Cercozoa. They ...

). The loss of flagella and scales has occurred in this group several times independently through evolution.

Taxonomy

The superclass Ventrifilosa was first described in 2012 by

Cavalier-Smith Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford. His research has led to discov ...

to unite

Thecofilosea Thecofilosea is a class of Cercozoa. References Cercozoa classes {{Cercozoa-stub ...

and

. However, the group proved to be

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of converg ...

because the

sarcomonad The sarcomonads () or class Sarcomonadea are a group of amoeboid biciliate protists in the phylum Cercozoa. They are characterized by a propensity to move through gliding on their posterior cilium or through filopodia, a lack of scales or e ...

s were excluded. Later, in 2018, it was expanded to include

, which belonged to the superclass Eoglissa before this change. The current classification of Ventrifilosa recognizes 3 classes, 20 orders and 60 families. *Class

**?Family Katabiidae **Subclass Paracercomonada ***Order Paracercomonadida **Subclass Pediglissa ***Order

Cercomonadida Cercomonads are small flagellates, widespread in aqueous habitats and common in soils. Characteristics The cells are generally around 10 μm in length, without any shell or covering. They produce filose pseudopods to capture bacteria, but do no ...

***Order

Glissomonadida The glissomonads are a group of bacterivorous gliding flagellated protists that compose the order Glissomonadida, in the amoeboflagellate phylum Cercozoa. They comprise a vast, largely undescribed diversity of soil and freshwater organisms. ...

*Class

**Subclass Placonuda ***Superorder Nudisarca ****Order Variglissida ****Order Marimonadida ***Superorder

Euglyphia Euglyphia can refer to: * Euglyphia (protist), a superorder of protists in the phylum Cercozoa * ''Diphthera'' (moth), a genus of moths with the alternative scientific name ''Euglyphia'' {{disambiguation ...

****Order

Euglyphida The euglyphids are a prominent group of filose amoebae that produce shells or tests from siliceous scales, plates, and sometimes spines. These elements are created within the cell and then assembled on its surface in a more or less regular arra ...

****Order Zoelucasida ***Superorder Discomonada ****Order Discomonadida **Subclass Placoperla ***Superorder Placofila ****Order

Thaumatomonadida Thaumatomonadida is an order of flagellates. Taxonomy Order Thaumatomonadida Shirkina 1987 * Genus '' Cowlomonas'' Scoble & Cavalier-Smith 2014 * Genus '' Heterochromonas'' Lee & Patterson 2000 * Family Esquamulidae Shiratori, Yabuki & Ishida 2 ...

****Order Discocelida ***Superorder Perlatia ****Order Spongomonadida ****Order Perlofilida **Subclass Krakenia ***Order Krakenida *Class

Thecofilosea Thecofilosea is a class of Cercozoa. References Cercozoa classes {{Cercozoa-stub ...

**Subclass Ventricleftia ***Order Ventricleftida **Subclass Eothecia ***Order Matazida ***Order Ebriida ***Order

Cryomonadida Cryomonadida is a group of heterotrophic Rhizaria, that belong to the Cercozoa. Characteristics Members of the Cryomonadida are single-celled organisms that are surrounded by a shell comprising layers of organic material. They possess two unequ ...

**Subclass

***Order Eodarida ***Order Opaloconchida **Subclass Tectosia ***Order

Tectofilosida The tectofilosids are a group of filose amoebae with shells. These are composed of organic materials and sometimes collected debris, in contrast to the euglyphids, which produce shells from siliceous scales. The shell usually has a single open ...

References

{{taxonbar, from=Q25368158 Cercozoa