Seisonidae is a family of

rotifer The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John H ...

s, found on the gills of '' Nebalia'', a marine crustacean. Peculiar among rotifers, males and females are both present and equal in size. Males and females are similar with paired gonads. It is considered to have diverged from the other rotifers early on, and in one treatment is placed in a separate class Seisonoidea. They have a large and elongate body with reduced corona. Their muscular system is similar to that of other rotifers: they have longitudinal muscles as well as open annular muscles.

Species

Two genera with total three species belong to Seisonidae: * ''

Paraseison ''Paraseison'' is a monotypic genus of rotifers The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate ...

'' Plate, 1887 ** ''

Paraseison annulatus ''Paraseison'' is a monotypic genus of rotifers The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate ...

'' (Claus, 1876) —

ectoparasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

of ''Nebalia'' * ''

Seison ''Seison'' is a genus of rotifers The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate animals. They ...

'' Grube, 1861 ** ''

Seison nebaliae ''Seison'' is a genus of rotifers The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate animals. They ...

'' Grube, 1861 – commensal of ''Nebalia'' ** ''

Seison africanus ''Seison'' is a genus of rotifers belonging to the family Seisonidae. Species: *'' Seison africanus'' *''Seison nebaliae ''Seison'' is a genus of rotifers The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel ...

'' Sorensen, Segers & Funch, 2005 — host is unknown.

References

Pararotatoria Rotifer families {{Rotifer-stub