The Vannellidae are a family of

Amoebozoa Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists, often possessing blunt, fingerlike, lobose pseudopods and tubular mitochondrial cristae. In traditional and currently no longer supported classi ...

, which are found in soil, fresh- and salt water. The most common genus is ''Vannella''.

Description

''Vannellidae'' tend to be flattened and fan-shaped during motion, although some are long and narrow, and have a prominent clear margin at the

anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

. In most amoebae, the

endoplasm Endoplasm generally refers to the inner (often granulated), dense part of a cell's cytoplasm. This is opposed to the ectoplasm which is the outer (non-granulated) layer of the cytoplasm, which is typically watery and immediately adjacent to the ...

glides forward through the center of the cell, but vannellids undergo a sort of rolling motion with the outer membrane sliding around like a tank tread. These amoebae are usually 10-40 μm in size, but some are smaller or larger. ''Vannellidae'' are surrounded by an outer covering called the

glycocalyx The glycocalyx, also known as the pericellular matrix, is a glycoprotein and glycolipid covering that surrounds the cell membranes of bacteria, epithelial cells, and other cells. In 1970, Martinez-Palomo discovered the cell coating in animal cells ...

, which is generally 10-20 nm across, though the thickness varies among species. In some species, a layer of hair-like filaments called glycostyles protrudes from the glycocalyx.

Taxonomy

Molecular phylogenies include them in the class

Flabellinia The Flabellinia are a subclass of Amoebozoa. During locomotion the cells are flattened and have a clear layer called ''hyaloplasm'' along the front margin. Some form slender subpseudopodia projecting outward from the hyaloplasm, but the cell ma ...

as a

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to the others, which have subpseudopodia.

References

Amoebozoa families Discosea {{Amoebozoa-stub