Relict Leopard Frog
The relict leopard frog (Rana onca) was first described in 1875 from a specimen collected near the Virgin River in Washington County, Utah. Subsequent reports and museum specimens provide evidence that this species had a relatively restricted range along portions of the Virgin, Muddy and Colorado Rivers, particularly in small springs that fed into those major drainages.
Although there was no scientific system of population monitoring in place, anecdotal evidence suggests that populations declined for a variety of reasons. In fact, by 1950, when the last known specimens were collected from Berry Spring in southern Utah, the species was considered to be extinct (Stebbins 1951, Platz 1984, M. Jennings 1988, Platz 1988). This belief persisted for approximately forty-one years, until the species was rediscovered at 2 springs on Lake Mead National Recreation Area in Nevada on April 24, 1991 (R. Haley pers. comm.). Morphological and genetic studies conducted since 1991 have confirmed the validity of this taxon (Jennings et al. 1995, Jaeger et al. 2001).