Mayflies (Insecta: Ephemeroptera) of Nevada, United States of America

This report provides the first comprehensive list of the species of mayflies that have been taken in the western U.S.A. state of Nevada. Of the western states, Nevada has had the poorest documentation in terms of Ephemeroptera fauna, with only one or very few locales having been recorded for only 38 species. One obvious reason for this historical neglect is that although the state is relatively large at 286,297 square kilometers, it is the driest of all U.S.A. states, resulting in relatively few permanent streams and severely limiting the number of habitats available for mayflies within its deserts. The Great Basin extends into part of the state mainly from Utah; much of western Nevada is in the rain shadow of the Sierra Nevada Mountain Chain; mountains within Nevada tend to be highly isolated and alkaline flats are common. A preliminary survey of the mayflies from the Humboldt River (Fig. 1), which runs east to west in the high desert of the northern part of the state, represents the only previous faunistic study centered over part of Nevada (Baumann and Kondratieff 2000). The first mayfly reported from Nevada was the common western species Siphlonurus occidentalis (Eaton) (Eaton 1885). Banks (1924) added two species, and Traver (1935) added a fourth. All other species were added since 1958.