''Chydorus'' is a genus of

Chydoridae Chydoridae is a family of water fleas in the order Anomopoda. There are more than 50 genera and 520 described species in Chydoridae. A lot of Chydoridae species are non-native species, many of which pose a great threat to aquatic ecosystems. Gen ...

. The genus was described in 1816 by

William Elford Leach William Elford Leach (2 February 1791 – 25 August 1836) was an English zoologist and marine biologist. Life and work Elford Leach was born at Hoe Gate, Plymouth, the son of an attorney. At the age of twelve he began a medical apprenticesh ...

. It has

cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ...

. It was found that centers of dispersion of two ''Chydorus'' groups were located in the European part of the continent and two others in

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

. One clade survived during harsh conditions of the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

glaciation in a northern refugium, while another clade survived in the south. Species include: * '' Chydorus gibbus'' * '' Chydorus globosus'' * '' Chydorus latus'' * '' Chydorus ovalis'' * '' Chydorus piger'' * '' Chydorus rylovi'' Mukhamediev, 1963 * '' Chydorus sinensis'' Frey, 1987 * '' Chydorus sphaericus'' (O.F. Müller, 1776)

References

{{Authority control Cladocera