The Tecopa pupfish (''Cyprinodon nevadensis calidae'') is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

subspecies of the Amargosa pupfish (''

Cyprinodon nevadensis ''Cyprinodon nevadensis'' is a species of pupfish in the genus ''Cyprinodon''. The species is also known as the Amargosa pupfish, but that name may also refer to one subspecies, ''Cyprinodon nevadensis amargosae''. All six subspecies are or wer ...

''). The small, heat-tolerant

pupfish Pupfish are a group of small killifish belonging to ten genera of the family Cyprinodontidae of ray-finned fish. Pupfish are especially noted for being found in extreme and isolated situations. They are primarily found in North America, South Am ...

was

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 elsew ...

to the outflows of a pair of

hot spring A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circ ...

s in the

Mojave Desert The Mojave Desert ( ; mov, Hayikwiir Mat'aar; es, Desierto de Mojave) is a desert in the rain shadow of the Sierra Nevada mountains in the Southwestern United States. It is named for the indigenous Mojave people. It is located primarily in ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. Habitat modifications and the introduction of non-native species led to its extinction in about 1970.

Taxonomy

The Tecopa pupfish is member of the genus ''

Cyprinodon ''Cyprinodon'' is a genus of pupfishes found in waters that range from fresh to hypersaline. The genus is primarily found in Mexico, the Caribbean Islands and southern United States (Arizona, California, Florida, Nevada, New Mexico, Oklahoma and ...

'' of the pupfish family Cyprinodontidae, a taxon of

killifish A killifish is any of various oviparous (egg-laying) cyprinodontiform fish (including families Aplocheilidae, Cyprinodontidae, Fundulidae, Profundulidae and Valenciidae). All together, there are 1,270 species of killifish, the biggest family ...

most diverse in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. Most

divergence In vector calculus, divergence is a vector operator that operates on a vector field, producing a scalar field giving the quantity of the vector field's source at each point. More technically, the divergence represents the volume density of the ...

of local ''Cyprinodon'' species likely took place during the early-to-mid

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

, a time when

pluvial lake A pluvial lake is a body of water that accumulated in a basin because of a greater moisture availability resulting from changes in temperature and/or precipitation. These intervals of greater moisture availability are not always contemporaneous ...

s intermittently filled the now-desert region, though some may have occurred during the last 10,000 years. The evaporation of the lakes resulted in the

geographic isolation Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

of small ''Cyprinodon'' populations in remnant wetlands and the

speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...

of ''C. nevadensis''. ''C. n. calidae'' was first described as a subspecies in 1948 by

Robert Rush Miller Robert Rush Miller (April 23, 1916 – February 10, 2003) "was an important figure in American ichthyology and conservation from 1940 to the 1990s." He was born in Colorado Springs, earned his bachelor's degree at University of California, Berke ...

, after six years of study. Miller also identified five other subspecies: the Amargosa River pupfish (''C. n. amargosae''), the Ash Meadows pupfish (''C. n. mionectes''), the Saratoga Springs pupfish (''C. n. nevadensis''), the Warm Springs pupfish (''C. n. pectoralis''), and the

Shoshone pupfish The Shoshone pupfish (''Cyprinodon nevadensis shoshone'') is a subspecies of ''Cyprinodon nevadensis'' from California in the United States. It is characterized by large scales and a "slab-sided," narrow, slender body, with the arch of the ventr ...

(''C. n. shoshone''). Other local ''Cyprinodons'' include the

Death Valley pupfish The Death Valley pupfish (''Cyprinodon salinus''), also known as Salt Creek pupfish, is a small species of fish in the family Cyprinodontidae found only in Death Valley National Park, California, United States. There are two recognized subspecie ...

(''Cyprinodon salinus''), the

Devil's Hole pupfish The Devils Hole pupfish (''Cyprinodon diabolis'') is a critically endangered species of the family Cyprinodontidae (pupfishes) found only in Devils Hole, a water-filled cavern in the US state of Nevada. It was first described as a species in ...

, (''Cyprinodon diabolis'') the desert pupfish (''

Cyprinodon macularius ''Cyprinodon'' is a genus of pupfishes found in waters that range from fresh to hypersaline. The genus is primarily found in Mexico, the Caribbean Islands and southern United States (Arizona, California, Florida, Nevada, New Mexico, Oklahoma and ...

'') and the

Owens pupfish The Owens pupfish (''Cyprinodon radiosus'') is a rare species of fish in the family Cyprinodontidae, the pupfish. It is Endemism, endemic to California in the United States, where it is limited to the Owens Valley. It is a federally listed endang ...

(''Cyprinodon radiosus'').

Description and behavior

The fish were about 1–1.5 inches (2.5–4 cm) in length. The

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

was positioned closer to the tail than the head. The

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

was small or sometimes absent, and had six

lepidotrichia Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

. Similar to some other ''Cyprinodons'', breeding males displayed a bright blue coloration. Females had between six and ten vertical stripes. ''C. n. calidae'' primarily ate

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

(blue-green algae). Invertebrates such as

mosquito larvae Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning "gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "lit ...

provided occasional nutrition. The fish were capable of surviving water temperatures of 110 degrees Fahrenheit (43 °C) or more.

Decline and extinction

Tecopa Hot Springs lies at an elevation of 1,411 feet (430 m), about 2 miles north of the town of

Tecopa Tecopa (formerly Brownsville) is a census-designated place (CDP) in the Mojave Desert, in Inyo County, California, United States. Tecopa is located south-southeast of Shoshone, at an elevation of . The population was 150 at the 2010 census, u ...

Inyo County, California Inyo County () is a county in the eastern central part of the U.S. state of California, located between the Sierra Nevada and the state of Nevada. In the 2020 census, the population was 19,016. The county seat is Independence. Inyo County is ...

. The outflows of the two

s are tributaries of the

Amargosa River The Amargosa River is an intermittent waterway, 185 miles (298 km) long, in southern Nevada and eastern California in the United States. It drains a high desert region, the Amargosa Valley in the Amargosa Desert northwest of Las Vegas, int ...

, and were the only place where ''C. n. calidae'' existed. The popularity of the springs in the 1950s and 1960s led to the extensive alteration of the pupfishes' habitat. During the construction of bathhouses, the hot spring pools were enlarged and the outflows diverted. In 1965, the outflows of the northern and southern hot springs were re-channeled and merged. The resulting swifter currents caused downstream water temperatures to rise above a level to which the pupfish were adapted. Modifications also allowed the related Amargosa River pupfish (''C. n. amargosae'') to migrate upstream from the Amargosa River and

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

ize with the Tecopa pupfish. In 1966, Miller found that the population at Tecopa Hot Springs was nearly extinct. A population was found at a reservoir at a nearby motel two years later, but its smaller scales suggested that it may have already hybridized with the Amargosa River pupfish. In 1970, concerns over this habitat alteration and the presence of non-native species such as the

bluegill The bluegill (''Lepomis macrochirus''), sometimes referred to as "bream", "brim", "sunny", or "copper nose" as is common in Texas, is a species of North American freshwater fish, native to and commonly found in streams, rivers, lakes, ponds and ...

and the

western mosquitofish The western Mosquitofish (''Gambusia affinis'') is a North American freshwater fish, also known commonly, if ambiguously, as simply Mosquitofish or by its generic name, ''Gambusia'', or by the common name gambezi. Its sister species, the easte ...

led to its inclusion in both Federal and California lists of endangered species. The last confirmed specimens of ''C. n. calidae'' were collected on February 2, 1970, and the subspecies was probably extinct by the next year. Further surveys in 1972 and 1977 returned no examples of the fish. In 1978,

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 ...

announced that it was considering delisting the fish, with Assistant

Secretary of the Interior Secretary of the Interior may refer to: * Secretary of the Interior (Mexico) * Interior Secretary of Pakistan * Secretary of the Interior and Local Government (Philippines) * United States Secretary of the Interior See also

*Interior ministry ...

Robert L. Herbst calling the loss "totally avoidable" and saying, "The human projects which so disrupted its habitat, if carefully planned, could have ensured its survival." In 1981, after an exhaustive search of over 40 locations, the Fish and Wildlife Service officially declared the fish extinct. It was the first animal removed from the provisions of the 1973

Endangered Species Act The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of ec ...

as a result of its extinction.

References

{{Taxonbar, from=Q2399695 Cyprinodon Pupfish, Tecopa Pupfish, Tecopa Pupfish, Tecopa Pupfish, Tecopa Amargosa Desert Desert National Wildlife Refuge Complex Natural history of Inyo County, California Taxa named by Robert Rush Miller Fish described in 1948 Fish of North America becoming extinct since 1500 Extinct animals of the United States Species made extinct by human activities Subspecies