Cercomonads are small

amoeboflagellate An amoeboflagellate ( amoeboflagellates) is any eukaryotic organism capable of behaving as an amoeba and as a flagellate at some point during their life cycle. Amoeboflagellates present both pseudopodia and at least one flagellum, often simultan ...

s, 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

pseudopod A pseudopod or pseudopodium (: 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 filaments and ...

s to capture

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

, but do not use them for locomotion, which usually takes place by gliding along surfaces. Most members have two

flagella A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

, one directed forward and one trailing under the cell, inserted at right angles near its anterior. The

nucleus Nucleus (: nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucleu ...

is connected to the flagellar bases and accompanied by a characteristic paranuclear body. 2023_Cercomonad

Classification

Genetic studies place the cercomonads among the

Cercozoa Cercozoa (now synonymised with Filosa) is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead united by phylogeny, molecular phylogenies of rRNA and actin or Ubiqu ...

, a diverse group of amoeboid and flagellate protozoans. They are divided into two families. * The

Heteromitidae Cercomonads are small amoeboflagellates, 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, bu ...

tend to be relatively rigid, and produce only temporary pseudopods. * The

Cercomonadidae Cercomonads are small amoeboflagellates, 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, bu ...

are more plastic, and when food supplies are plentiful may become

amoeboid An amoeba (; less commonly spelled ameba or amœba; : amoebas (less commonly, amebas) or amoebae (amebae) ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and r ...

and even

multinucleate Multinucleate cells (also known as multinucleated cells or polynuclear cells) are eukaryotic cells that have more than one nucleus, i.e., multiple nuclei share one common cytoplasm. Mitosis in multinucleate cells can occur either in a coordinate ...

. The classification of genera and species continues to undergo revision. Some genera have been merged, like ''Cercomonas'' and '' Cercobodo''. Others like ''

Helkesimastix Cercomonads are small amoeboflagellates, 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, bu ...

'', ''

Sainouron Cercomonads are small amoeboflagellates, 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 bacterium, ba ...

'' and ''

Cholamonas Cercomonads are small amoeboflagellates, 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, bu ...

'' have been moved to Helkesida, while the rest of the family

has been moved to

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. They ...

. Most recently, the family

Paracercomonadidae The paracercomonads are a group of cercozoan protists. Taxonomically, they comprise the family Paracercomonadidae, order Paracercomonadida and subclass Paracercomonada. Due to their morphological similarities to the cercomonads, members of this ...

, previously included in this order, has been separated into its own order

Paracercomonadida The paracercomonads are a group of cercozoan protists. Taxonomically, they comprise the family Paracercomonadidae, order Paracercomonadida and subclass Paracercomonada. Due to their morphological similarities to the cercomonads, members of this ...

. This change has made Cercomonadidae the only existing family of cercomonads. * '' Cavernomonas'' Vickerman 2009 * ''

Cercomonas Cercomonads are small amoeboflagellates, 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, b ...

'' Dujardin 1841 emend. Karpov et al. 2006 non emend. Ekelund et al. 2004 [''Cercobodo'' Krassilstschick 1886; ''Cercomastix'' Lemmermann 1913; ''Dimastigamoeba'' Blochmann 1894; ?''Mukdeniamonas'' Skwortzov 1960; ?''Changia'' Skwortzov 1960 non Sun 1924; ?''Reptomonas'' Kent 1880; ''Dimorpha'' Klebs 1892 non Gruber 1882] * ''Eocercomonas'' Karpov et al. 2006 * ''Filomonas'' Cavalier-Smith & Karpov 2012 * ''Neocercomonas'' Ekelund, Daugbjerg & Fredslund 2004

References

{{Taxonbar, from=Q724194 Cercozoa