''Richardsonius'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of freshwater ray-finned fishes belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Leuciscidae Leuciscidae is a family of freshwater ray-finned fishes, formerly classified as a subfamily of the Cyprinidae, which contains the true minnows. Members of the Old World (OW) clade of minnows within this subfamily are known as European minnow ...

, the shiners, daces and minnows. The fishes in this genus are found in western

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. Commonly known as redside shiners, that term is also used to refer to '' Richardsonius balteatus'' specifically. The genus is named after naturalist Sir John Richardson (1787–1865), who described ''R. balteatus'' in 1836.

Species

''Richardsonius'' contains the following valid species: * '' Richardsonius balteatus'' ( J. Richardson, 1836) (Redside shiner) * '' Richardsonius egregius'' ( Girard, 1858) (Lahontan redside) In addition, a single fossil species †'' Richardsonius durranti'' Smith, 1975 is known from the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Glenns Ferry Formation of Idaho.

References

* * Pogonichthyinae Fish of North America Fish of the United States {{Leuciscinae-stub