Although the individual Cyprinodon species often have a highly specific habitat, overall the genus occurs in a remarkable range of places, such as springs (including those isolated in deserts), pools, lakes, coastal lagoons, creeks, streams and rivers. Their salinity and temperature range is very broad, like those living in hot springs (taken to the extreme in C. julimes in water up to 46°C or 115°F, and C. pachycephalus up to 49°C or 120°F),[10][11] and those of hypersaline habitats where the salinity far exceeds that of sea water.[12][13] Certain species may even experience very large variations in the temperature and salinity over a relatively short period. For example, some populations of C. variegatus live in water where the temperature has been known to change from 15 to −1.8°C (59 to 29°F) in less than 24 hours (in the coldest temperatures they bury into the substrate).[14] Some populations of C. nevadensis tolerate water temperatures between 2 and 44°C (36–111°F), and C. salinus live in waters where the temperature may change by as much as 19°C (34°F) in a day and 40°C (72°F) in a season.[14][15] Furthermore, the salinity of C. salinus' habitat may vary from less than one-third of that of sea water to almost five times as much as sea water in a season.[12]
Conservation status
Most species in the genus are seriously threatened. C. arcuatus, C. ceciliae, C. inmemoriam, C. nevadensis calidae and an undescribed species popularly known as the "Perrito de Sandia" are already extinct.[15][16][17][18][19]C. arcuatus was restricted to springs in the US state of Arizona and probably also in the Mexican state of Sonora,[16] while all the others were restricted to spring systems in Mexico.[20][21]
Three species from southwestern Nuevo León, C. alvarezi, C. longidorsalis and C. veronicae, have become extinct in the wild, only surviving in captivity.[20][22][23] A few other Mexican species still considered endangered or vulnerable by the IUCN, including at least C. maya, C. simus and C. verecundus of Lake Chichancanab, also appear to only survive in captivity.[24][25] Several others have very small remaining populations in the wild.[21] Among the species that survive in the wild, the rarest is perhaps C. diabolis from the tiny Devils Hole in Nevada; in recent decades its population has fluctuated between a few tens and a few hundred individuals.[26] Primary threats to pupfish are habitat loss due to water extraction, drought and pollution, and introduced species.[3][21]
Most Cyprinodon species feed on algae, cyanobacteria and detritus, but may also supplement their diet with small crustaceans and aquatic insect larvae.[15][24] Some species mainly feed on small animals like aquatic insects.[13]C. variegatus, a species that otherwise has a diet typical of pupfish, will clean other fish by feeding on parasites on their body.[27]
In the two places where several species live together they have diverged into different niches, including the fish-eatingC. maya (Lake Chichancanab), zooplankton-eating C. simus (Lake Chichancanab), amphipod- and bivalve-eating C. labiosus and C. verecundus (Lake Chichancanab), scale-eatingC. desquamator (San Salvador Island lakes), and ostracod- and gastropod-eating C. brontotheroides (San Salvador Island lakes).[2][24]
Cyprinodon pupfish are short-lived, typically reaching an age of no more than a year in the wild,[15] although some may reach as much as three years.[27] Especially those from habitats that experience major environmental fluctuations (for example, large variations in temperature) rapidly reach maturity and are already able to breed when 1–1.5 month old.[15] Despite some species' ability to survive in a wide temperature range, their requirements for breeding often are much more specific. For example, although some populations of C. nevadensis can live in water that ranges between 2 and 44°C (36–111°F), they only breed from 24to 30°C (75–86°F).[15] However, there are exceptions like C. rubrofluviatilis that will breed at a relative wide range from 13to 34°C (55–93°F).[13] Consequently, pupfish living in stable habitats breed year-round, but those in more seasonal habitats generally only at certain times of the year where the conditions are optimal.[15] When breeding, males assume a relatively bright nuptial coloration.[15]
There are two primary breeding strategies: In species of small isolated habitats like springs, each large male (or medium-sized male, if large males are absent) defends a territory and displays to visiting females that will lay their eggs inside the territory.[15][28] In at least some species, small males will attempt to fertilize eggs by sneaking into a territory of a larger male.[28] Once deposited, neither sex cares for the eggs, although they do get a level of protection by being inside the territory of a male. A male will attempt to attract several females to lay their eggs in his territory and a female may lay eggs in the territories of several males.[15] Another breeding strategy is used by species that inhabit rivers. Here the males do not maintain a territory and groups of pupfish gather to breed. A male typically will lead a female to the edge of the group to spawn, although on occasion it may occur in the middle of the group.[15] The eggs of Cyprinodon pupfish are adhesive and stick to the substrate,[15] or they are covered in sand.[27]
Species
Cyprinodon brontotheroides (shown) and C. desquamator are both restricted to hypersaline lakes in the BahamasCyprinodon eremus in shallow water, which is preferred by most species in this genusCyprinodon julimes was only scientifically described in 2009Cyprinodon rubrofluviatilis, a relatively common species from TexasCyprinodon desquamator (shown), the scale-eating pupfish, in its natural habitat on San Salvador Island, BahamasCyprinodon macrolepis male in an aquarium.
There are currently 49 recognized species in this genus:[1][2]
12345678Martin, C. H., and P. C. Wainwright (2013). Multiple Fitness Peaks on the Adaptive Landscape Drive Adaptive Radiation in the Wild. Science 339(6116): 208-211.
123Contreras-Balderas, S.; L. Lozano-Vilano (1996). "Extinction of most Sandia and Potosí valleys (Nuevo León, Mexico) endemic pupfishes, crayfishes and snails". Ichthyol. Explor. Freshwaters. 7 (1): 33–40.
123Hassan-Williams, C.; T.H. Bonner (2007). "Cyprinodon rubrofluviatilis". Texas Freshwater Fishes, Texas State University - San Marcos, Department of Biology. Retrieved 26 August 2019.
12Bennett, W.A.; T.L. Beitinger (1997). "Temperature Tolerance of the Sheepshead Minnow, Cyprinodon variegatus". Copeia. 1997 (1): 77–87. doi:10.2307/1447842. JSTOR1447842.
123Ceballos, G.; E.D. Pardo; L.M. Estévez; H.E. Pérez, eds. (2016). Los peces dulceacuícolas de México en peligro de extinción. Fondo de Cultura Económic. ISBN978-607-16-4087-1.
↑"Devils Hole Pupfish". U.S. Fish and Wildlife Service. December 2, 2013. Retrieved 7 October 2018.
123Hassan-Williams, C.; T.H. Bonner (2007). "Cyprinodon variegatus". Texas Freshwater Fishes, Texas State University - San Marcos, Department of Biology. Retrieved 26 August 2019.
12Leiser, J.K.; M. Itzkowitz (2002). "The relative costs and benefits of territorial defense and the two conditional male mating tactics in the Comanche Springs pupfish (Cyprinodon elegans)". Acta Ethol. 5 (1): 65–72. doi:10.1007/s10211-002-0066-1. S2CID42642403.
↑Miller, Robert R. (1945). "Four new species of fossil cyprinodont fishes from eastern California". Journal of the Washington Academy of Sciences. 35 (10): 315–321. ISSN0043-0439. JSTOR24531079.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
