Leon Springs pupfish
Leon’s Spring, Rio Grande del Norte (Leon Springs, Texas; Baird and Girard 1853).
Etymology/Derivation of Scientific Name
Cyprin – Greek, meaning “carp”; odon – Greek, meaning “tooth”; bovinus – Latin, meaning “likeness or belonging to a cow or ox”.
Cyprinodon bovinus Baird and Girard 1853:389-390; Echelle and Miller (1974); Hubbs et al. 1991:30.
Maximum size: 56 mm TL (Page and Burr 1991).
Coloration: Dorsal fin unicolor; lateral scales evenly colored; lateral blotches of female longer than deep; dark terminal caudal bar of adult males about one-third of caudal length (Baird and Girard 1853; Hubbs et al. 1991). Gray brown above; whitish below; dorsal and caudal fins dusky gray; pale yellow bar on caudal fin between base and black terminal band; large male has yellow dorsal fin edge, wide jet black edge on yellow caudal fin (Echelle and Miller 1974). Rectangular lateral blotches and numerous blotches on lower side of female (rarely on male; Baird and Girard 1853; Echelle and Miller 1974; Echelle and Echelle 1978).
Counts: 24 or 25 lateral scale rows (Echelle and Miller 1974; Hubbs et al. 1991); 9-11 dorsal fin rays; 9-12 anal fin rays; usually 7 pelvic fin rays; 19-21 (18-23) rakers on 1st gill arch; 2 mandibular pores (Echelle and Miller 1974).
Mouth position: Upturned mouth (Page and Burr 1991).
Body shape: Distance from origin of dorsal fin to end of hypural plate less than distance from origin of dorsal to anterior nostril (Hubbs et al. 1991). Body depth is deep, body width is wide, head length is long (Echelle and Echelle 1978).
External morphology: Abdomen fully scaled (Echelle and Miller 1974; Hubbs et al. 1991).
Internal morphology: Teeth compressed and with three cusps (Hubbs et al. 1991).
Distribution (Native and Introduced)
Texas distribution: Species occurs in Leon Creek, a flood tributary of the Pecos River (Pecos County) in western Texas (Hubbs 1980; Hubbs et al. 1991; Garrett et al. 2002).
Abundance/Conservation status (Federal, State, NGO)
Endangered status by U.S. Fish and Wildlife Service in 1980 (Hubbs et al. 1991; Garrett et al. 2002). Population in Diamond Y Draw estimated at <10,000 adults (Echelle, pers. comm. in: Garrett et al. 2002). Cyprinodon bovinus nearly became extinct due to hybridization with the introduced sheepshead minnow (Cyprinodon variegatus; Hubbs et al. 1991). C. bovinus was once found in Leon Springs (15 miles southwest of Leon Creek) but was extirpated from the area when the springs were impounded and pumped dry (Hubbs et al. 1991). Hubbs (1957) considered species extinct. However, species was rediscovered in Diamond Y Spring (Echelle and Miller 1974; Minckley et al. 1991; Garrett et al. 2002).
Macrohabitat: Endemic to a small spring-fed system in Texas (Echelle and Miller 1974; Echelle and Echelle 1997). Species inhabits springs, outlet marshes, and marshes; eurythermal (Minckley et al. 1991).
Mesohabitat: Most abundant in quiet water near edges of shallow pools, especially those areas with minimal growths of vegetation (Echelle and Miller 1974). Springs are typically quite hard, with high levels of silica, sulphates, and chlorides (Rohde and Guillory 1980); occurs in saline (10-15 ppt) habitat (Echelle et al. 1987).
Spawning season: Some spawning occurs most of the year, but spawning peaks in middle to late July (Kennedy 1977); peak spawning at temperatures of 24-29°C.
Spawning behavior: In male preference experiments, C. bovinus females chose randomly between C. bovinus males and C. variegatus males (Garrett 1980; Garrett et al. 2002). Looping, a preliminary courtship behavior, was observed in C. bovinus population; males were observed defending territories in the shallowest waters (Echelle and Miller 1974). Leiser and Itzkowitz (2003) compared territories of males defending in a cluster to males defending in dispersed localities. Leiser et al. (2006) studied the disruption of dear enemy recognition among neighboring males by female C. bovinus.
Age at maturation: Individuals ≥ 29 mm SL were mature (Kennedy 1977).
Growth and Population structure:
Longevity: 20-23 months (Kennedy 1977).
Food habits: Generalist feeder; main food items are diatoms, amphipods, and ostracods (Kennedy 1977). Species engages in pit-digging (behavior largely restricted to males) probably in an effort to locate buried food items (Minckley and Arnold 1969; Kennedy 1977).
Phylogeny and morphologically similar fishes
The Pecos River pupfish (C. pecosensis) has intermediate belly scalation; dark blotches are sparse on lower side of female; no yellow in dorsal and caudal fins, narrow black bar on end of caudal fin of male (Echelle and Echelle 1978). The Red River pupfish (C. rubrofluviatilis) has completely naked belly; dark blotches on lower side absent; has yellow pectoral fins, face and venter; has narrow black bar on caudal fin edge; no yellow in dorsal and caudal fins of male (Echelle and Echelle 1978). C. bovinus differs from the Conchos pupfish (C. eximius) in having the pectoral fins slightly more pointed, more numerous gill rakers (18-23 vs. 12-18), 2 rather than 0 mandibular pores, 7 versus 7 or 8 preopercular pores, and usually 2 or 3 rather than 3 or 4 lacrimal pores (Echelle and Miller 1974). The sheepshead minnow (C. variegatus) lacks many small dark blotches on lower side and lacks yellow on dorsal and caudal fins of male (Page and Burr 1991); C. variegatus (from the Texas coast) usually has 21-23 rakers on 1st arch (Echelle and Miller 1974). C. bovinus and C. variegatus hybridize naturally (Kennedy 1977; Echelle and Echelle 1997). Cokendolpher (1980) included C. bovinus in intergeneric Cyprinodon hybridization experiments.
Commercial or Environmental Importance
Cyprinodon bovinus is threatened by hybridization with the introduced sheepshead minnow (C. variegatus), pollution, and physical modification of habitat (Echelle and Miller 1974; Kennedy 1977; Hubbs 1980; Minckley et al. 1991; Garrett et al. 2002). Efforts to eradicate C. bovinus X C. variegatus hybrids have been made (Kennedy 1977; Hubbs et al. 1978; Hubbs 1980) and genetically pure C. bovinus (captive stock from Dexter National Fish Hatchery) have been released in areas, successfully reducing frequencies of non-native alleles (Echelle et al. 1987; Garrett et al. 2002). Future management of this species should include systematic monitoring of population and genetic structure (Echelle and Echelle 1997; Garrett et al. 2002), as well as further releases of C. bovinus from the Dexter National Fish Hatchery to help insure natural genetic structure in nature (Garrett et al. 2002).
Since 1990, most of the area inhabited by C. bovinus (a 608 ha area known as Diamond Y Spring Preserve) has been under the management of The Nature Conservancy of Texas (Echelle and Echelle 1997; Garrett et al 2002).
[Additional literature noting collection of this species from Texas locations includes, but is not limited to the following: Edds and Echelle (1989).]
Baird, S.F., and C. Girard. 1853. Descriptions of new species of fishes collected by Mr. John H. Clark, on the U. S. and Mexican Boundary Survey, under Lt. Col. Jas. D. Graham. Proc. Acad. Nat. Sci. Philadelphia 6(7):387-390.
Cokendolpher, J.C. 1980. Hybridization experiments with the genus Cyprinodon (Teleostei: Cyprinodontidae). Copeia 1980(1):173-176.
Echelle, A.A., and A.F. Echelle. 1978. The Pecos River pupfish, Cyprinodon pecosensis n. sp. (Cyprinodontidae), with comments on its evolutionary origin. Copeia 1978(4):569-582.
Echelle, A.A., and A.F. Echelle. 1997. Genetic introgression of endemic taxa by non-natives: a case study with Leon Springs pupfish and sheepshead minnow. Cons. Biol. 11: 153–161.
Echelle, A.A, and R.R. Miller. 1974. Rediscovery and redescription of the Leon Springs pupfish, Cyprinodon bovinus, from Pecos County, Texas. Southwest. Nat. 19: 179–190.
Echelle, A.A., A.F. Echelle and D.R. Edds. 1987. Population structure of four pupfish species (Cyprinodontidae: Cyprinodon) from the Chihuahuan desert region of New Mexico and Texas: allozymic variation. Copeia 1987: 668–681.
Edds, D.R., and A.A. Echelle. 1989. Genetic comparisons of hatchery and natural stocks of small endangered fishes: Leon Springs pupfish, Comanche Springs pupfish, and Pecos gambusia. Trans. Amer. Fish. Soc. 118:441-446.
Garrett, G.P. 1980. Species specificity in the mating systems of Cyprinodon variegatus and Cyprinodon bovinus. Proc. Desert Fishes Council 11: 54–59.
Hubbs, C. 1957. Distributional patterns of Texas fresh-water fishes. Southwestern Naturalist 2(2/3): 89–104.
Hubbs, C. 1980. Solution to the C. bovinus problem: eradication of a pupfish genome. Proc. Desert Fishes Council 10: 9–18.
Hubbs, C., R.J. Edwards, and G.P. Garrett. 1991. An annotated checklist of the freshwater fishes of Texas, with keys to identification of species. Texas Journal of Science, Supplement 43(4):1-56.
Hubbs, C., T. Lucier, E. Marsh, G.P. Garrett, R.J. Edwards, and E. Milstead. 1978. Results of an eradication program on the ecological relationships of fishes in Leon Creek, Texas. Southwestern Naturalist 23: 487–496.
Kennedy, S.E. 1977. Life history of the Leon Springs pupfish, Cyprinodon bovinus. Copeia 1977: 93–103.
Leiser, J.K., and M. Itzkowitz. 2003. The costs and benefits of territorial neighbours in a Texas pupfish (Cyprinodon bovinus). Behavior 140:97-112.
Leiser, J.K., C.M. Bryant, and M. Itzkowitz. 2006. Disruption of dear enemy recognition among neighboring males by female Leon Springs pupfish, Cyprinodon bovinus. Ethology 112(2006):417-423.
Minckley, W.L., and E.T. Arnold. 1969. “Pit-digging”, a behavioral adaptation in pupfishes (Genus Cyprinodon). J. Ariz. Acad. Sci. 5:254-257.
Minckley, W.L., G.K. Meffe, and D.L. Soltz. 1991. Conservation and management of short-lived fishes: the cyprinodontoids. pp. 247–282. In: W.L. Minckley & J.E. Deacon (ed.) Battle Against Extinction, Native Fish Management in the American West, The University of Arizona Press, Tucson.
Page, L. M. and B. M. Burr. 1991. A field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin Company, Boston, Massachusetts. 432 pp.
Rohde, F.C., and V. Guillory. 1980. Cyprinodon bovinus (Baird and Girard), Leon Springs pupfish. p. 493. In: D. S. Lee, C. R. Gilbert, C. H. Hocutt, R. E. Jenkins, D. E. McAllister & J. R. Stauffer, Jr. (eds.), Atlas of North American freshwater fishes, North Carolina State Museum of Natural History, Raleigh, 854 pp.