The Little Colorado spinedace (''Lepidomeda vittata'') is a species of

ray-finned fish 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 h ...

in the family Cyprinidae. It is found only in

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

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 territori ...

Description

The Little Colorado spinedace is small, generally less than 10 cm in length. The scales are in a lateral line of usually more than 90. The second spine of the dorsal fin is strong. The dorsal fin is moderately high and acute, and its depressed length is 5.2 to 5.8 cm predorsal length. There are eight anal fin rays, and rarely nine. The pharyngeal teeth are in two rows. The Little Colorado spinedace sides are usually silvery, darker above and sometimes white below, rarely with lateral blotches. The upper side and back are a bit of a bluish or lead grey. The breeding Little Colorado Spinedace males have bases of paired fins watery-yellow to orange or red-orange, otherwise however the fins are clear, and parts of the belly are watery-yellow.

Range

The Little Colorado spinedace is endemic to the Little Colorado River and north-flowing tributaries, flowing through Coconino, Navajo, and Apache Counties of Arizona. The historical distribution is similar to the current distribution but the species may have possibly historically occurred in the

Zuni River The Zuni (Zuñi) River is a tributary of the Little Colorado River in the southwestern United States. It has its origin in Cibola County, New Mexico, in the Zuñi Mountains at the Continental Divide. The river flows off the western slopes of the ...

watershed south of Gallup, New Mexico. The Little Colorado spinedace are now considered

extirpated Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...

from the Silver Creek and its tributaries. Four populations of spinedace exist in Arizona with populations still found in the mainstream of Little Colorado, Nutrioso Creek, Clear Creek, as well as Chevelon Creek.

Habitat

The Little Colorado spinedace is found in water ranging from 0.16-1.3 meters in-depth, but most abundant in depths of around 0.6 meters. The fish are most common in slow to moderate water currents, over fine gravel bottoms. They normally avoid deep, heavily shaded pools and shallow, open areas. They generally prefer unshaded pools with rocks or undercut banks for cover. Temperatures where populations exist generally range from 14-26 degrees Celsius. Young of the year are most abundant on uniformly turbulent riffles 10 to 25 cm in depth.

Population trends

Populations of this species fluctuate dramatically from year to year, and probably reflect cyclic periods of drought and/or increased rainfall. Populations are thought to be declining, however, due to alteration of habitat through reduced streamflow and interaction with introduced fish species.

Management factors

Limiting factors include road construction, timber harvest operations, stream gravel removal, and chemical treatment of streams. Additional limiting factors and concerns include decreased streamflow, impoundment of water, and interaction with and predation by, introduced exotic fishes. Predation by rainbow trout has been strongly suggested as an important factor in the success and distribution of ''L. vittata''.Blinn, D.W., C. Runck, D.A. Clark, and J.N. Rinne. 1993. Effects of Rainbow Trout predation on Little Colorado Spinedace. in Transactions of the American Fisheries Society 122:139-143.

Notes

References

{{Taxonbar, from=Q306910 Lepidomeda Fish of the Western United States Fauna of the Southwestern United States Natural history of Arizona Taxa named by Edward Drinker Cope Fish described in 1874 Taxonomy articles created by Polbot ESA threatened species Freshwater fish of North America