Cercomonad
Encyclopedia
Cercomonads are small flagellate
s, widespread in aqueous habitats and common in soils.
s to capture bacteria, but do not use them for locomotion, which usually takes place by gliding along surfaces.
Most members have two flagella
, one directed forward and one trailing under the cell, inserted at right angles near its anterior. The nucleus
is connected to the flagellar bases and accompanied by a characteristic paranuclear body.
, a diverse group of amoeboid and flagellate protozoans.
They are divided into two families.
The classification of genera and species continues to undergo revision. Some genera have been merged, like Cercomonas and Cercobodo, and some have been moved to other groups.
Flagellate
Flagellates are organisms with one or more whip-like organelles called flagella. Some cells in animals may be flagellate, for instance the spermatozoa of most phyla. Flowering plants do not produce flagellate cells, but ferns, mosses, green algae, some gymnosperms and other closely related plants...
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 pseudopodPseudopod
Pseudopods or pseudopodia are temporary projections of eukaryotic cells. Cells that possess this faculty are generally referred to as amoeboids. Pseudopodia extend and contract by the reversible assembly of actin subunits into microfilaments...
s to capture bacteria, but do not use them for locomotion, which usually takes place by gliding along surfaces.
Most members have two flagella
Flagellum
A flagellum is a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and plays the dual role of locomotion and sense organ, being sensitive to chemicals and temperatures outside the cell. There are some notable differences between prokaryotic and...
, one directed forward and one trailing under the cell, inserted at right angles near its anterior. The nucleus
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...
is connected to the flagellar bases and accompanied by a characteristic paranuclear body.
Classification
Genetic studies place the cercomonads among the CercozoaCercozoa
The Cercozoa are a group of protists. They are sometimes described as a kingdom.-Characteristics:The group includes most amoeboids and flagellates that feed by means of filose pseudopods. These may be restricted to part of the cell surface, but there is never a true cytostome or mouth as found in...
, a diverse group of amoeboid and flagellate protozoans.
They are divided into two families.
- The Heteromitidae tend to be relatively rigid, and produce only temporary pseudopods.
- The Cercomonadidae are more plastic, and when food supplies are plentiful may become amoeboidAmoeboidAmoeboids are single-celled life-forms characterized by an irregular shape."Amoeboid" and "amœba" are often used interchangeably even by biologists, and especially refer to a creature moving by using pseudopodia. Most references to "amoebas" or "amoebae" are to amoeboids in general rather than to...
and even multinucleateMultinucleateMultinucleate cells have more than one nucleus per cell, which is the result of nuclear division not being followed by cytokinesis. As a consequence, multiple nuclei share one common cytoplasm. This can be the consequence of a disturbed cell cycle control Multinucleate (also multinucleated,...
.
The classification of genera and species continues to undergo revision. Some genera have been merged, like Cercomonas and Cercobodo, and some have been moved to other groups.