The Leon Springs pupfish (''Cyprinodon bovinus'') is a species of

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

in the family Cyprinodontidae. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

Pecos County, Texas Pecos County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 15,193. The county seat is Fort Stockton. The county was created in 1871 and organized in 1875.. By Glenn Justice and John Leffler. Retri ...

in the United States. It is a federally listed endangered species. The Leon Springs pupfish is found at the shallow edges of spring-fed wetland pools, where it is most frequently observed in areas without vegetation.. Its diet consists of

diatoms A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...

, amphipods, and

ostracod Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...

s. This fish was first discovered in 1851 at Leon Springs, near

Fort Stockton, Texas Fort Stockton is a city in and the county seat of Pecos County, Texas, United States. It is located on Interstate 10, future Interstate 14, U.S. Highways 67, 285, and 385, and the Santa Fe Railroad, northwest of San Antonio and southeas ...

. Leon Springs was impounded, poisoned, stocked with game fish,Kennedy, S. E. (1977)
Life history of the Leon Springs Pupfish, ''Cyprinodon bovinus''.
''Copeia'' 1977(1) 93. and drained, and the fish was considered extinct by 1938. In the 1960s it was rediscovered at Diamond Y Spring a few miles away.USFWS
Listing of Leon Springs Pupfish as endangered with critical habitat.
''Federal Register'' August 15, 1980. It is also found in the Diamond Y Draw, a

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainag ...

of the

Pecos River The Pecos River ( es, Río Pecos) originates in north-central New Mexico and flows into Texas, emptying into the Rio Grande. Its headwaters are on the eastern slope of the Sangre de Cristo mountain range in Mora County north of Pecos, New Mexico ...

.Garrett, G., et al. (2002)
Threatened fishes of the world: ''Cyprinodon bovinus'' Baird & Girard, 1853 (Cyprinodontidae).
''Environmental Biology of Fishes'' 64(4) 442.

References

Cyprinodon Endemic fauna of Texas Fish of the Western United States Freshwater fish of the United States Pecos County, Texas Endangered fish Endangered fauna of the United States Taxa named by Spencer Fullerton Baird Taxa named by Charles Frédéric Girard Fish described in 1853 Taxonomy articles created by Polbot ESA endangered species {{Cyprinodontiformes-stub