The Bonneville Cutthroat Trout
The Bonneville Cutthroat Trout (Oncorhyncus clarki utah) was evolutionarily isolated by the recession of the late Pleistocene Lake Bonneville. The isolation of small populations of trout in the headwaters of streams of the Bonneville Drainage basin resulted in phenotypic variation among populations as seen here. Above is a Bonneville Cutthroat Trout from the Bear River Drainage in Wyoming and below is a Bonneville Trout from the Snake Valley Drainage in Nevada. Pure populations of Bonneville Cutthroat Trout exist in drainages in Utah, Nevada, Wyoming and Idaho. Recently, the Bonneville Cutthroat was designated the official fish of the State of Utah.
For more information on the Bonneville Cutthroat Trout see abstracts from the American Fisheries Society Meeting and the recent article in the Great Basin Naturalist 1997 JAN, V57 N1:11-20 entitled "Distribution and abundance of native Bonneville cutthroat trout (Oncorhynchus clarki utah) in southwestern Utah." by Hepworth, DK, Ottenbacher, MJ and Berg, LN.
Images taken from "Native Trout of North America" by Robert H. Smith