WSPC00146 - Laserfiche WebLink

Home Browse Search

002031 publications, Cope stated that the "type locslity" of ~. stomias is the Kansas River at Fort Riley, Kansas. The Kaneas River, however, has nc native trcut. The confusion originated with an Army expediticn under the command of Lt. F. T. Bryant, traveling from Fort Riley, Kansas, to Fort Bridger, Wyoming, and back again in 1856. A surgeon, Dr. W. R. Hammond, acccmpanied the expedition and made natural history collections; among his collections were two specimens of cutthroat trout. The expedition traversed parts of the Kansas, North Platte, South Platte, and Green River drainages in Kansas, Nebraska, Wyoming and Colorado. Cutthroat trout could have been collected only in the Green River or South Platte drainages. The problem is that all of the specimens collected on the expedition were simply labeled 'Fort Riley, Kansas' (the terminus of the expedition) and shipped to the Philadelphia Academy of Sciences, where Cope later saw the cutthroat trout specimens and named Salmo stomias." Jordan (1891) redefined stomias and limited its use to the cutthroat trout native to the South Platte and Arkansae River drainages. . Jordan also appears to be the first person to use the common name "greenback" for this trout in the literature. All cutthroat trout are currently placed in the genus Oncorhvnchus, with the current scientific name of the greenback being Oncorhvnchus clarki stomias. . TaXODomv , The cutthroat trout, Oncorhvnchus clarki (formerly Salmo clarki), is a prime example of a polytypic speciee. Trout referred to as Q. clarki are found in both coastal and inland streams from Alaska to New Mexico, and within this range the species has evolved into numerous subspecies or geographic races. Many subspecies undoubtedly are polyphyletic, having evolved directly from other subspecies rather than (monophyletically) from a centrally localized stem group. This evolutionary pattern, ccupled with the deClining abundance of "pure" inland trout, and extensive hybridization with introduced species (e.g. rainbow trout Q. mvkiss), has made it difficult to unravel the myriad systematic problems within inland Q. clarki (Gold 1977). The taxonomy of the greenback cutthroat trout (Q. ~. stomias) has been described by Wernsman (1973), Behnke (1973, 1979), and Behnke and Zarn (1976). The following description of the subspecies is from Behnke and Zarn (1976): "Taxonomic criteria for ~.clarki stomias remain tentative due to the extreme rareness of pure populations and to the scarcity cf ancient museum specimens. Even so, scale counts (180-230) made from available specimens consistently exhibit the highest values of any cutthroat trout, or any trout in the genus Salmo. It may be assumed that extremely high scale counts are characteristic of pure populations of ~. ~. stomias, with some suggestion that those populations native to the South Platte Basin may show slightly higher counts than those native to the Arkansas drainage. The greenback cutthroat trout displays typically lower numbers of pyloric caeca and vertebrae than most other subspecies of 2' clarki, but much overlap_Qc~urs in"these characters. Salmo clarki stomias undoubtedly derived via an ancient headwater transfer of the Colorado River basin to the South Platte River drainage (and then to the Arkansas River drainage) and for this reason shares many similarities with the Colorado River cutthroat, ~. E. Dleuriticus. The striking spotting pattern and intense coloration which can develop in mature fish are the most diagnostic field characteristics of the greenback trout. 2' ~. stomias typically displays the largest and most pronounced spots of any cutthroat trout. Round to oblong in shape, the spots appear concentrated posteriorly on the caudal peduncle area. Coloration is similar to that found in 2. ~. oleuriticus and tends toward 4