NEVADA MAYFLIES, AN UPDATED LIST.

C.M. Murvosh¹ and G.F. Edmunds, Jr.². ¹Dept. Biol. Sci., University of Nevada, Las Vegas, Las Vegas, NV 89154, ²Dept. Biol., Univ. Utah, Salt Lake City, Ut. 84112

We are planning to complete a faunal assessment of the mayflies of Nevada and plot species distributions on maps. Nevada is a huge state (790 km long and 512 km wide), most of which lies in a geographic/hydrologic region called the “Great Basin” where no surface water leaves except by evaporation. This is part of the Basin and Range geological province. The lentic habitats, which dominated this area during Pleistocene pluvial times, are mostly gone, and some think of the state as barren desert. The many north-south trending mountains (horsts), however, have a variety of numerous streams that flow toward the basin valleys (grabens). Some of these are difficult to reach, and often require a four-wheel drive or a high clearance vehicle, but mayflies have been collected from many of them in recent years. We presently identify 64 species in 36 genera and 12 families of Ephemeroptera.