''Cyprinodon longidorsalis'', the cachorrito de charco palmal or La Palma pupfish, is a species of

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 family

Cyprinodontidae Pupfish are a group of small killifish belonging to ten genus, 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, S ...

. It was

endemic Endemism is the state of a species being found only 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 foun ...

to the Ojo de Agua la Presa in southwestern

Nuevo Leon Nuevo is the Spanish word for "new". It may refer to: * Nuevology, California, a town in California, United States * Nuevo (band), featuring singer and musician Peter Godwin * Nuevo (Bayamón), a settlement in Puerto Rico * "Nuevo", Spanish-langu ...

state in

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 ...

, but became

extinct in the wild A species that is extinct in the wild (EW) is one that has been categorized by the International Union for Conservation of Nature as only consisting of living members kept in captivity or as a naturalized population outside its historic range ...

in 1994 due to habitat loss (now survives only in captivity). The same freshwater spring system was the home of three other pupfish: '' Cyprinodon ceciliae'' (extinct), '' Cyprinodon inmemoriam'' (extinct) and '' Cyprinodon veronicae'' (extinct in the wild, survives in captivity). Although these were from the same spring system, each was restricted to its own individual spring pool. The Charco La Palma pool and its spring had a combined area of about and was no more than at the deepest point, making the range of the La Palma pupfish perhaps the smallest known for any vertebrate species. This tiny spring pond also was the home of a now-extinct,

undescribed species In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. U ...

of '' Cambarellus'' crayfish. The La Palma pupfish is a

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 ...

which can grow up to long. Their color ranges from almost gray to a deep blue. It is somewhat distinctive for having a single long dorsal fin which leans back.

References

longidorsalis Fish described in 1993 Endemic fish of Mexico Freshwater fish of Mexico Taxa named by María de Lourdes Lozano-Vilano Taxa named by Salvador Contreras-Balderas Fish of North America becoming extinct since 1500 Taxonomy articles created by Polbot {{Cyprinodontiformes-stub