The loach minnow (''Tiaroga cobitis'') is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of freshwater

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

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. It is the only species in the

monospecific genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

''Tiaroga''. It occurs in streams and small rivers throughout the

Gila River The Gila River (; O'odham ima Keli Akimel or simply Akimel, Quechan: Haa Siʼil, Maricopa language: Xiil) is a tributary of the Colorado River flowing through New Mexico and Arizona in the United States. The river drains an arid watershed of ...

and San Pedro River systems in

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

, and

Sonora Sonora (), officially Estado Libre y Soberano de Sonora (), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is divided into Municipalities of Sonora, 72 ...

; it is now considered extinct in Mexico.

Description

Loach minnow has an elongated, compressed body with its size rarely exceeding in length.Minckley, W.L. 1973. Fishes of Arizona. Arizona Game and Fish Department, Phoenix. pp. 133–135. This species have an olivaceous body, highly blotched with darker pigment. They have dirty-white spots before and behind base of dorsal fin, and on lower and upper sides base of caudal. Breeding males have vivid red-orange markings on bases of fins, body, and lower head. Breeding females become yellow on their fin and lower body. The loach minnow has whitish spots that are present on the origin and insertion of the dorsal fin as well as on the dorsal and ventral portions of the caudal fin base, this distinguishes the loach minnow from the similar speckled dace for field identification.

Biology

Loach minnows are short-lived fishes, depending on their environment and different characteristics of individual population. Spawning is observed to take place from late winter in early summer. Their eggs are deposited on the bottom of flattened rocks, and the number of eggs can range from 5 to more than 250 per rock, with average of 52 to 63 eggs per rock. A female can contain 150 to 1200 mature ova. Males turn red on their fins and above their mouths when they are ready to breed.

Habitat and food

Loach minnows can be found at turbulent, rocky riffles of mainstream rivers. They prefer moderate to swift current velocity and gravel substrates. Members of this species are opportunistic benthic insectivores: they seek food at the bottom substrate for riffle-dwelling larval ephemeropterans, simuliid, and chironomid dipterans.

Conservation

Loach minnow was proposed (USDI, Fish and Wildlife Service SFWS1985) and subsequently listed (USFWS 1986) as a threatened species. Critical habitat was proposed (USFWS 1985) and took effect on April 7, 1994. The critical habitat designation was subject to controversy and litigation, causing it to be rescinded, redesignated and altered. In 2012, the loach minnow was declared "endangered" alongside the

spikedace The spikedace (''Meda fulgida'') is an endangered species of ray-finned fish in the family Leuciscidae. It is found in Arizona and New Mexico in the United States. It lives in fast-moving streams. Description The maximum length of the spikedace ...

(''Meda fulgida''), with which it shares much of its range.

References

{{Taxonbar, from=Q3757073 Pogonichthyinae Freshwater fish of Mexico Freshwater fish of the United States Fish of the Western United States Extinct animals of Mexico Fauna of the Sonoran Desert Natural history of Sonora Gila River Endangered fish Taxa named by Charles Frédéric Girard Fish described in 1856 Species that are or were threatened by habitat fragmentation Species that are or were threatened by damming Species that are or were threatened by invasive species