The longfin dace (''Agosia chrysogaster'') 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), ...

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

in the leuciscid

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 ...

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Cypriniformes Cypriniformes is an order of ray-finned fish, which includes many families and genera of cyprinid ( carps and their kin) fish, such as barbs, loaches, botias, and minnows (among others). Cypriniformes is an "order-within-an-order", placed ...

. It is the only member of the

monotypic 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 "unisp ...

genus ''Agosia'' and is found in southwestern

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. The

Gila longfin dace The Gila longfin dace (''Agosia chrysogaster chrysogaster'') is a subspecies of the longfin dace found in Arizona. It is considered the nominate subspecies of the longfin dace. Description The only other form of fish closely related to Gila ...

is considered the nominate subspecies, and the

Yaqui longfin dace The Yaqui longfin dace is a small fish of the American Southwest and northern Mexico, and considered a form of the longfin dace. It is often referred to as ''Agosia chrysogaster'' sp 1. Description The Yaqui longfin dace is similar to the G ...

is considered a form. The genus name ''Agosia'' is of

Native American Native Americans or Native American usually refers to Native Americans in the United States. Related terms and peoples include: Ethnic groups * Indigenous peoples of the Americas, the pre-Columbian peoples of North, South, and Central America ...

origin, and the species name ''chrysogaster'' is derived from

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

, where ''chrysós'' means "gold" and ''gastḗr'' means "belly".

Description

Longfin dace have a bluntly shaped snout and head with a slightly subterminal mouth. The upper jaw contains a small barbel and tends to protrude above the lower jaw. The body is

fusiform Fusiform (from Latin ''fusus'' ‘spindle’) means having a spindle (textiles), spindle-like shape that is wide in the middle and tapers at both ends. It is similar to the lemon (geometry), lemon-shape, but often implies a focal broadening of a ...

and covered with small scales. Longfin dace have 70-95 scales along their

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

, 7-9

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

rays, and 9

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

rays. An adult longfin dace has a maximum

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

of , although it rarely reaches .

Age estimation Age or AGE may refer to: Time and its effects * Age, the amount of time someone has been alive or something has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ** ...

with scales and length-based grouping suggested that most longfin dace live less than two years.Winther, John Kristian. "Age and Growth of the Longfin Dace, Agosia Chrysogaster Girard." (1962). https://digitalrepository.unm.edu/biol_etds/268

Distribution and habitat

Longfin dace are

native Native may refer to: People * '' Jus sanguinis'', nationality by blood * '' Jus soli'', nationality by location of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Nat ...

to the deserts of southwestern North America, notably in the

American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, p ...

states of

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 ...

and

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 northern

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

states of

Sinaloa Sinaloa (), officially the (), is one of the 31 states which, along with Mexico City, compose the Federal Entities of Mexico. It is divided into 18 municipalities, and its capital city is Culiacán Rosales. It is located in northwest Mexic ...

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 ...

. The longfin dace is tolerant to a wide range of water temperature, and is found in low elevation desert streams to mountain brooks. They prefer streams that have sandy or gravel bottoms, typically with overhanging banks or cover to use as protection. During periods of

drought A drought is a period of drier-than-normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, ...

, longfin dace may seek refuge in algae and detritus mats.Minckley, W.L. and W.E. Barber. 1971. Some aspects of biology of the longfin dace, a cyprinid fish characteristic of streams in the Sonoran Desert. Southwest Naturalist 15(4): 459-564. Agosia chrysogaster

Diet

Longfin dace are

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

and opportunistic feeders. They can feed on invertebrates, zooplankton, algae, and detritus.Grimm, N. B. 1988. Feeding dynamics, nitrogen budgets, and ecosystem role of a desert stream omnivore, Agosia chrysogaster (Pisces: Cyprinidae). Environmental Biology of Fishes (21): 143-152.

Reproduction

Longfin dace reach sexual maturity within a year and are able to spawn throughout the year, although most spawning occurs in spring and late summer. Longfin dace will create depressions in the sand to deposit their eggs, which provide cover from predators while the eggs develop and hatch. The eggs and juveniles receive no parental care.

Management

In the United States, longfin dace are considered secure but have been reduced in abundance due to habitat change and introduced fishes.

References

{{Taxonbar, from=Q1102004, from2=Q8191638 Pogonichthyinae Fish of North America Fish described in 1856 Taxa named by Charles Frédéric Girard Cyprinid fish of North America Endemic fish of the United States Fish of the Western United States Freshwater fish of the United States Fauna of the Southwestern United States