Picture by Chad Thomas, Texas State University - San Marcos
Chihuahua River (= Rio Chuviscar, at Chihuahua City) Mexico (Girard 1859; Miller 1976; Minckley 1980).
Etymology/Derivation of Scientific Name
Cyprinodon eximius Girard 1859:158.
Maximum size: 50 mm TL (Page and Burr 1991).
Coloration: Lateral blotches of female deeper than long; dark terminal caudal bar of adult males about one-fourth of caudal depth (Hubbs et al. 2008). Page and Burr (1991) described coloration as follows: Faint brown blotches on silver side, rows of small brown spots on upper side. Gray-brown above; white below; dusky median fins. Breeding male has yellow-orange dorsal fin; dark brown bars along side; black spots, dashes on front half, wide black edge on caudal fin (Page and Burr 1991).
Counts: Lateral scale rows 26-27 (Page and Burr 1991; Hubbs et al. 2008). Page and Burr (1991) listed additional counts as follows: 12-18 gill rakers; 6-7 pelvic rays; 0 mandibular pores.
Mouth position: Upturned (Page and Burr 1991).
Body shape: Distance from origin of dorsal fin to end of hypural plate less than the distance from origin of dorsal to anterior nostril (Hubbs et al. 2008).
External morphology: Abdomen fully scaled (Hubbs et al. 2008).
Distribution (Native and Introduced)
U.S. distribution: Ranges from the Rio Conchos, Chihuahua, Mexico to the Devils River, Texas (Minckley et al. 1991; Hubbs et al. 2008).
Texas distribution: Devils River and Alamito Creek (Hubbs et al. 2008). The Devils River (TX) and Alamito Creek (TX) populations are morphologically and biochemically distinct from the Rio Conchos (Mexico) populations (Hubbs et al. 1991, 2008).
Abundance/Conservation status (Federal, State, NGO)
State Threatened (Texas; Hubbs et al. 2008). Cyprinodon eximius, the Conchos pupfish, was listed as Threatened by the American Fisheries Society (Jelks et al. 2008); species threatened by the present or threatened destruction, modification, or reduction of habitat or range. Cyprinodon eximius ssp., the Devils River pupfish, was listed as Threatened by the American Fisheries Society (Jelks et al. 2008); categories of threats: present or threatened destruction, modification, or reduction of habitat or range; and a narrowly restricted range. Species listed as Threatened in Mexico (Edwards 2001; Garrett et al. 2005). Species abundant in the Rio Chuviscar (Edwards et al. (2002) and elsewhere in the Rio Conchos basin (Edwards 2001; Garrett et al. 2005). The reestablished population in Dolan Creek thriving (Garrett et al. 1992), most other Rio Grande tributary populations sparse (Edwards 2001; Garrett and Edwards 2001; Garrett et al. 2005). According to Cantu and Winemiller (1997), C. eximius ranked among the eighth most abundant species in the Devils River study area. Minckley et al (1991) reported this species as Vulnerable due to habitat degradation and loss. Species was locally abundant in Rio Conchos basin, Chihuahua, Mexico, a major tributary of Rio Grande; Rio Sauz basin (Minckley and Koehn 1965; Minckley 1980); and tributaries of Rio Grande east to Val Verde Co., Texas (Miller 1976; Minckley 1980).
Macrohabitat: Typical of sloughs, backwaters, and margins of larger streams, channels of creeks (in Mexico), and mouths of creeks tributary to larger rivers; rarely in headsprings (Minckley 1980; Minckley et al. 1991).
Mesohabitat: Species dominated shallow, isolated pool habitat in the Devils River, Texas (Cantu and Winemiller 1997). Found in sandy to gravelly streams, in clear, shallow waters (Contreras-Balderas 1974).
Age at maturation:
Growth and Population structure:
Food habits: Herbivorous, bottom feeder (Contreras-Balderas 1974). Some populations excavate feeding pits in soft substrates (Minckley and Arnold 1969; Minckley 1980).
Phylogeny and morphologically similar fishes
Cyprinodon eximius can be distinguished by the caudal fin on mature males having black spots on the interradial membranes and the caudal fin bar being relatively wide preceded by a clear band (Miller 1976; Edwards 2001; Garrett et al. 2005).
Cyprinodon eximius is the most widespread member of the distinctive complex of seven species occupying the Chihuahuan Desert Region of north central Mexico and southern Texas (Miller 1976; Minckley 1980). C. eximius belongs to a complex of 12 pupfish species inhabiting an area which was once extensive Pleistocene bodies of water in the Chihuahuan Desert (Echelle and Echelle 1998; Edwards 2001; Garrett et al. 2005).
Commercial or Environmental Importance
Cyprinodon eximius first taken in the Devils River (Texas) in 1953 during surveys by the Texas Game and Fish Commission (Hubbs and Garrett 1990). The Texas range of this species was reduced to a small portion of the Devils River by human actions including reservoir filling and stream rotenone treatment, and an effort was made in 1979 to reestablish the species in a previous location by transporting 200 individuals from the remaining population upstream, above a large waterfall, to Dolan Creek (Davis 1980; Garrett 1980; Hubbs and Garrett 1990; Edwards 2001; Edwards et al. 2004; Garrett et al. 2005).
[Additional literature noting collection of this species from Texas locations includes, but is not limited to the following: Cokendolpher (1980); Platania (1990); Echelle et al. (2005).]
Cantu, N.E.V., and K.O. Winemiller. 1997. Structure and habitat associations of Devils River fish assemblages. Southwestern Naturalist 42(3):265-278.
Cokendolpher, J.C. 1980. Hybridization experiments with the genus Cyprinodon (Teleostei, Cyprinodontidae). Copeia (1):173-176.
Contreras-Balderas, S. 1974. Speciation aspects and man-made community composition changes in Chihuahuan Desert fishes. pp. 405-431 in: Transactions of the Symposium on the Biological Resources of the Chihuahuan Desert Region United States and Mexico. National Park Service Transactions and Proceedings Series 3. U.S. Department of the Interior.
Davis, J.R. 1980. Rediscovery, distribution, and population status of Cyprinodon eximius (Cyprinodontidae) in Devil’s River, Texas. The Southwestern Naturalist 25(1):81-88.
Echelle, A.A. and A.F. Echelle. 1998. Evolutionary relationships of pupfishes in the Cyprinodon eximius complex (Atherinomorpha: Cyprinodontiformes). Copeia(4):852-865.
Echelle, A.A., E.W. Carson, A.F. Echelle, R.A. van den Bussche, T.E. Dowling, and A. Meyer. 2005. Historical biogeography of the new-world pupfish genus Cyprinodon (Teleostei: Cyprinodontidae). Copeia 2:320-339.
Edwards, R.J. 2001. Ecological profiles for selected stream-dwelling Texas freshwater fishes III. Report to the Texas Water Development Board. 59 pp.
Edwards, R.J., G.P. Garrett, and E. Marsh-Matthews. 2002. Conservation and status of the fish communities inhabiting the Rio Conchos basin and middle Rio Grande, Mexico and U.S.A. Reviews in Fish Biology and Fisheries 12:119-132.
Edwards, R.J., G.P. Garrett, and N.L. Allan. 2004. Aquifer dependent fishes of the Edwards Plateau region, Chapter 13. pp. 253-268 in: Mace, R.E., E.S. Angle, and W.F. Mulligan, III (Eds.). Aquifers of the Edwards Plateau. Texas Water Development Board. 360 pp.
Garrett, G.P. 1980. Update on some of the protected and endangered fishes of Texas. Proc. Des. Fish. Council 11: 34–36.
Garrett, G.P., and R.J. Edwards. 2001. Regional ecology and environmental issues in West Texas, Chapter 5. pp. 56-65 in: Mace, R.E., W.F. Mullican, Jr., and E.S. Angle (Eds.). Aquifers of West Texas. Texas Water Development Board.
Garrett, G.P., C. Hubbs, and R.J. Edwards. 2005. Threatened fishes of the world: Cyprinodon eximius Girard 1859 (Cyprinodontidae). Environmental Biology of Fishes 72:98.
Garrett, G.P., R.J. Edwards, and A.H. Price. 1992. Distribution and status of the Devils River minnow, Dionda diaboli. The Southwestern Naturalist 37(3):259-267.
Girard, C.F. 1859. Ichthyological notices. Proc. Acad. Nat. Sci. Phila. 11:157-161.
Hubbs, C., and G.P. Garrett. 1990. Reestablishment of Cyprinodon eximius (Cyprinodontidae) and status of Dionda diaboli (Cyprinidae) in the vicinity of Dolan Creek, Val Verde Co., Texas. The Southwestern Naturalist 35(4):446-448.
Hubbs, C., R.J. Edwards, and G.P. Garrett. 2008. An annotated checklist of the freshwater fishes of Texas, with keys to identification of species. Texas Journal of Science, Supplement, 2nd edition 43(4):1-87.
Jelks, H.L., S.J. Walsh, N.M. Burkhead, S. Contreras-Balderas, E. Diaz-Pardo, D.A. Hendrickson, J. Lyons, N.E. Mandrak, F. McCormick, J.S. Nelson, S.P. Platania, B.A. Porter, C.B. Renaud, J.J. Schmitter-Soto, E.B. Taylor, and M.L. Warren, Jr. 2008. Conservation status of imperiled North American freshwater and diadromous fishes. Fisheries 33(8):372-407.
Miller, R.R. 1976. Four new pupfishes of the genus Cyprinodon from Mexico, with a key to the C. eximius complex. Bulletin Southern California Academy of Science 75:68-75.
Minckley, W.L. 1980. Cyprinodon eximius (Girard), Conchos pupfish. pp. 496 in D. S. Lee et al., Atlas of North American Freshwater Fishes. N. C. State Mus. Nat. Hist., Raleigh, i-r+854 pp.
Minckley, W.L., and R.K. Koehn. 1965. Re-discovery of the fish fauna of the Sauz Basin, Northern Chihuahua, Mexico. Southwestern Naturalist 10(4):313-315.
Minckley, W.L. and E.T. Arnold. 1969. “Pit digging" a behavioral feeding adaptation in pupfishes (Genus Cyprinodon). Journal of the Arizona Academy of Science 5:254-257.
Minckley, W.L., G.K. Meffe, and D.L. Soltz. 1991. Conservation and management of short-lives fishes: the cyprinodontoids, Chapter 15. pp. 247-282 in: Minckley, W.L., and J.E. Deacon (Eds.). Battle Against Extinction: Native Fish Management in the American West. University of Arizona Press, Tucson, Arizona. 517 pp.
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.
Platania, S.P. 1990. The ichthyofauna of the Rio Grande drainage, Texas and Mexico, from Boquillas to San Ygnacio. U.S. Fish and Wildlife Service. 100 pp.