''Rhizamoeba'' is a small genus of free-living marine naked lobose

amoebae 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 ...

in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

family Rhizamoebidae in the order

Leptomyxida Leptomyxida is an order of Amoebozoa. It includes species such as ''Flabellula citata'', ''Paraflabellula hoguae'', ''Paraflabellula reniformis'', ''Rhizamoeba saxonica'' and ''Leptomyxa reticulata''. Taxonomy The taxonomy of Leptomyxida as rev ...

. It is most closely related to ''

Leptomyxa ''Leptomyxa'' is a free-living genus of lobose naked multinucleate amoebae in the order Leptomyxida that inhabits freshwater, soil and mosses. It is very closely related to the genus ''Rhizamoeba'', and some species have been moved between the ...

'' and ''

Flabellula ''Flabellula'' is a genus of Amoebozoa Amoebozoa is a major Taxonomy (biology), taxonomic group containing about 2,400 described species of Amoeba, amoeboid protists, often possessing blunt, fingerlike, Pseudopod#Morphology, lobose pseudopods ...

'', and some species have been moved to ''

'' due to molecular data.

Morphology

Members of ''Rhizamoeba'' are characterized by their morphology when they move, which is usually monopodial (with a single ramification), alternating between a slug-like shape and a fan shape. They have either one

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 ...

or multiple (less than 50) nuclei.

Classification

The

paraphyly Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

of the genus caused the transfer of two previously rhizamoeban species into ''

'': '' R. australiensis'' and '' R. neglecta''. As a result, only 3 species are currently confirmed as ''Rhizamoeba'': * ''

Rhizamoeba saxonica ''Rhizamoeba'' is a small genus of free-living marine naked lobose amoebae in the monotypic family Rhizamoebidae in the order Leptomyxida. It is most closely related to ''Leptomyxa'' and ''Flabellula'', and some species have been moved to '' ...

'' * ''

Rhizamoeba polyura ''Rhizamoeba'' is a small genus of free-living marine naked lobose amoebae in the monotypic family Rhizamoebidae in the order Leptomyxida. It is most closely related to ''Leptomyxa'' and ''Flabellula'', and some species have been moved to ''Le ...

'' * ''

Rhizamoeba matisi ''Rhizamoeba'' is a small genus of free-living marine naked lobose amoebae in the monotypic family Rhizamoebidae in the order Leptomyxida. It is most closely related to ''Leptomyxa'' and ''Flabellula'', and some species have been moved to ''Le ...

'' Other possible species are not yet confirmed due to lack of published data or poor documentation. Some of these are: '' R. schnepfii'' (considered ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a ...

'' since it has not been deposited to any culture collection), ''

Trichamoeba caerulea ''Trichamoeba'' is a genus of Amoebozoa Amoebozoa is a major Taxonomy (biology), taxonomic group containing about 2,400 described species of Amoeba, amoeboid protists, often possessing blunt, fingerlike, Pseudopod#Morphology, lobose pseudopods ...

'' and ''

Trichamoeba clava ''Trichamoeba'' is a genus of Amoebozoa Amoebozoa is a major Taxonomy (biology), taxonomic group containing about 2,400 described species of Amoeba, amoeboid protists, often possessing blunt, fingerlike, Pseudopod#Morphology, lobose pseudopods ...

'' (both transferred to ''Rhizamoeba'' in 1980 but poorly documented), ''

Amoeba clavarioides 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 re ...

'' (identified as ''R. clavarioides'' through light microscopy), ''

Polychaos timidum Polychaos is an amoeboid genus in the Amoebozoa group. Several characters unite the species in this genus. The pseudopods meld at their bases when the organism is moving, and have dorsal, longitudinal ridges. The nucleus is oval or ellipsoidal ...

'' (identified as ''R. timidum'' through light microscopy), etc.

References

Amoebozoa genera Tubulinea {{Amoebozoa-stub