The sturgeon chub (''Macrhybopsis gelida'') is a species of

ray-finned Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

minnow Minnow is the common name for a number of species of small freshwater fish, belonging to several genera of the families Cyprinidae and Leuciscidae. They are also known in Ireland as pinkeens. Smaller fish in the subfamily Leusciscidae are co ...

fish in the family

Cyprinidae Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest verte ...

. It is found only in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. It is a species of concern in the Charles M. Russell National Wildlife Refuge in

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

Names and documentation

The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

was collected in the Milk River in Montana, and described by

Charles Frédéric Girard Charles Frédéric Girard (8 March 1822 – 29 January 1895) was a French biologist specializing in ichthyology and herpetology. Born in Mulhouse, France, he studied at the College of Neuchâtel, Switzerland, as a student of Louis Agassiz. In ...

in 1856.Smith, Philip Wayne. ''The Fishes of Illinois.'' Chicago: University of Illinois Press, 2002, p. 78. Girard named it ''Gobio gelidus'', but it was reclassified as ''Hybopsis gelidus'' in 1900 and ''Macrhybopsis gelidus'' in 1935. A new classification of ''Hybopsis gelida'' was suggested in 1965.

Description and habitat

The sturgeon chub is slender, streamlined fish with a long, flat snout.Marshall Cavendish Corporation. ''Endangered Wildlife and Plants of the World.'' New York: Marshall Cavendish, 2001, p. 267. The snout resembles that of a

sturgeon Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretace ...

, which gives the fish its name. Adults grow to be about in length. Johnsgard, Paul A. ''The Nature of Nebraska: Ecology and Biodiversity.'' Lincoln, Neb.: University of Nebraska Press, 2005, p. 174. There is a small

barbel Barbel may refer to: *Barbel (anatomy), a whisker-like organ near the mouth found in some fish (notably catfish, loaches and cyprinids) and turtles *Barbel (fish), a common name for certain species of fish **''Barbus barbus'', a species of cyprinid ...

near the corner of the mouth, and small pustules on the throat. The

scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number w ...

on the sturgeon chub's back and sides have a small ridge-like projection known as a "keel". The purpose of the keel is not established, but may help the fish stabilize and orient itself in fast currents or as a means of detecting currents. The eyes are small and it does not see well. The fish's color ranges from silvery-white on the belly to silvery sides, with a light-brown back.Pflieger, William L. and Smith, Pat. ''The Fishes of Missouri.'' Jefferson City, Mo.: Missouri Department of Conservation, 1997, p. 9. The tail is deeply forked, with the lower lobe darker than the upper lobe. The body fins are triangular, slightly rounded, and straight-edged (unlike the sicklefin chub).Page, Lawrence M. and Burr, Brooks. ''Peterson Field Guide to Freshwater Fishes of North America North of Mexico.'' Boston: Houghton Mifflin Harcourt, 2011, p. 104. The last dorsal fin ray extends beyond the first ray of the depressed fin. Little is known about its feeding habits,Marshall Cavendish Corporation, p. 268. although it does have teeth in its throat. The body is covered with

taste bud Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as lingual papillae, papillae found on the upper surface of the tongue, soft palate, upper e ...

s which help it locate food. It lives in waters which are little populated by other small fish, but can be found associating with the

flathead chub The flathead chub (''Platygobio gracilis'') is a species of fish in the carp family, Cyprinidae. It is the only member of the monotypic genus ''Platygobio''.Froese, R. and D. Pauly, Eds. (2011)''Platygobio''.FishBase. It is native to North Americ ...

, sicklefin chub, and speckled chub. Sturgeon chub exhibits little

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

, and neither sex exhibits color changes during breeding. However, the male does develop small

tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection ...

s behind the gills during breeding. It lays eggs on gravel or clean sand to reproduce. Breeding probably occurs in June.Smith, p. 79. The habitat of the sturgeon chub is murky river bottoms in fast-flowing streams with gravel bottoms. Its habitat extends over the Missouri River and its primary tributaries, the lower

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...

in the states of

Mississippi Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...

and

Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...

, and some streams in northeastern

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

. Increased silt and the construction of

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

s (which cause silt to settle and slow river currents) have destroyed extensive portions of its habitat. It remains common in the middle Missouri River, but rare elsewhere. The

United States Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...

(FWS) estimated in 2001 that it only inhabited about 59 percent of its former range.Stukel, E.D. "Sturgeon and Sicklefin Chubs." ''South Dakota Conservation Digest.'' May/June 2001, p. 25.

Names and documentation

Description and habitat

References

Further reading