The fatlips minnow (''Phenacobius crassilabrum'') is a species of

suckermouth In fish, a suckermouth is a ventrally-oriented (inferior) mouth adapted for grazing on algae and small organisms that grow on submerged objects. All Loricariidae possess a suckermouth as do the cypriniform algae eaters of the genus ''Gyrinocheilus' ...

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 c ...

that was first described in the upper

Tennessee River The Tennessee River is the largest tributary of the Ohio River. It is approximately long and is located in the southeastern United States in the Tennessee Valley. The river was once popularly known as the Cherokee River, among other names, ...

system. No fewer than 20 specimens were used for description, and the epithet ''crassilabrum'' (from the Latin ''crassus'' meaning thick or fat and labrum, or lip) was assigned to the species, separating it from '' Phenacobius catostomus,'' with which it had previously been identified. The first holotype specimen collected in 1947 was an adult female in length from the

River A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

Geographic distribution

The distribution of the fatlips minnow is restricted to North America, where it occurs in the upper Tennessee River drainage in western

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

, western

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...

, eastern

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

and northeastern

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the ...

. Its habitat is gravel and

riffles A riffle is a shallow landform in a flowing channel. Colloquially, it is a shallow place in a river where water flows quickly past rocks. However, in geology a riffle has specific characteristics. Topographic, sedimentary and hydraulic indica ...

in small to medium creeks. The fatlips minnow is believed to have arisen from a ''P. catostomus'' -like stock population that re-invaded the upper Tennessee River via reciprocal stream piracy. A genetic sister relationship between ''P. crassilabrum'' and '' P. uranops'' has been consistently resolved. The ranges of ''P. crassilabrum'' and ''P. uranops'' complement one another in the Tennessee River system, with the former opting for higher elevations. In Virginia, ''P. crassilabrum'' occupies the lower free-flowing portion of the South Fork of

Holston River The Holston River is a river that flows from Kingsport, Tennessee, to Knoxville, Tennessee. Along with its three major forks (North Fork, Middle Fork and South Fork), it comprises a major river system that drains much of northeastern Tennessee ...

and Laurel Creek. There are documented instances of nonindigenous (out-of-range) occurrences of ''Phenacobius'' species; these are believed to be a result of fishermen releasing their unused baitfish into local bodies of water.Nico, L., J. Larson, and A. Fusaro. 2013
Phenacobius mirabilis
USGS Nonindigenous Aquatic Species Database, Gainesville, FL. Revision Date: 12/20/2011 The current population of ''P. crassilabrum'' is presumed to be about 10,000 individuals.

Ecology

''P. crassilabrum'' is known to favor gravel riffles in the warm clear waters of small to medium-sized streams and rivers. Species of the genus ''Phenacobius'' remain near the bottom of streams, rooting in the ground for their prey of

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

and aquatic insects such as

mayfly Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the ord ...

and

caddisfly The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the ...

larvae A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

.Pflieger, W. L. 1997. The Fishes of Missouri, revised edition. Missouri Department of Conservation, Jefferson City.

Life history

Breeding activity has not been observed in ''P. crassilabrum''. Spawning for other ''Phenacobius'' species occurs in the spring and summer (April to August).Tomelleri, J.R., and K.D. Fausch. 2003
Wildlife in Danger Native minnows of the eastern plains
Colorado Division of Wildlife. (Accessed June 29, 2003).

Spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquat ...

events take place in the preferred gravelly riffles, allowing the released eggs to seek out nooks and crannies within the substrate. The maximum life span described in the genus is three years.

Management

''P. crassilabrum,'' while existing in small numbers in comparison to other species sharing its ecosystem, is considered to be of the

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

in terms of conservation status (

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

) and its population is considered stable. An additional factor to consider is the movement of non-native fish into the range of ''P. crassilabrum,'' threatening habitat and resource availability.

References

{{Taxonbar, from=Q1105009 Phenacobius Taxa named by Wendell L. Minckley Taxa named by James Edward Craddock Fish described in 1962