7017 - Laserfiche WebLink

Home Browse Search

reproductive isolating mechanisms have broken down due to habitat disturbence. In a pilot study of upper basin Gila, employs photographs of specimens on centimeter grid board (see Tyus et al., 1982, above) in conjunction with digitizer pad and computer to analyze variation. Based on comparison of recent and older material conjectures that extensive hybridization has occurred within past 20 years and that the three main river species are in danger of "coalesceing" into one or two. Concludes that samples examined contain a few "pure" cvpha and many intermediates, some of which were "partially" elegans. Speculates that bonytail genes may be rare in the upper basin except in hybrids. Overall, a decidedly different view from Smith et al. (1979), a study based on older material. Provides an artificial key to young and adult chubs for field use which incorporates problem forms and hybrids. 1983. Smith, G.R., R.R. Miller, and W.D. Sable. Systematic studies of the Colorado River chubs of the genus Gila. Proc. Desert. Fishes Coun. 8 (1976):221-222. See Smith et al. (1979) above. 1984. Berry, C.R., Jr. Hematology of four rare Colorado River fishes. Copeia 1984:790-793. Based on samples taken from hatchery-reared specimens, documents significant differences in several hematological characteristics between Gila cvpha and G. elegans. However these were not intended to have a taxonomic application. 1984. Miller, R.R., and G.R. Smith. Fish remains from Stanton's Cave, Grand Canyon of the Colorado, Arizona, with notes on the taxonomy of Gila cvpha; pp. 58-65, in: R.C. Euler, ed., The archaeology, geology, and paleobiology of Stanton's Cave, Grand Canyon National Park, Arizona. Grand Canyon Nat. Hist. Assn. Monogr. 6. 141 p. In the course of examining bones of Gila spp. from cave deposits, careful comparisons of osteological features were made revealing several skeletal characters of value in separating the species. 1985. Archer, D.L, L.R. Kaeding, B.D. Burdick, and C. W. McAda. A study of the endangered fishes of the upper Colorado River. U.S. Fish & Wildlife Ser. Rpt., Grand Junction, CO. 132 p. Points out that hybrid combinations of Gila spp. are suspected from several habitats in the upper Colorado River basin, including Yampa, Whirlpool and Desolation canyons of 16