PROC. ENTOMOL. SOC. WASH. 107(1), 2005, pp. 190-199 THE MAYFLIES (EPHEMEROPTERA) OF ALASKA, INCLUDING A NEW SPECIES OF HEPTAGENIIDAE R. P. Randolph and W. R McCafferty (RPR) Division of Evolution and Ecology, University of California, Davis, CA 95616 (e-mail:
[email protected]); (WPM) Department of Entomology, Purdue Univer-sity, West Lafayette, IN 47907 (e-mail:
[email protected]) Abstract. — Forty-six species of mayflies (Ephemeroptera) are reported from Alaska, and 27 of those are reported from the state for the first time. Nominal species in the genera Callibaetis Eaton, Caudatella Edmunds, Ecdyonurus Eaton, Ironodes Traver, Paralepto-phlebia Lestage, Plauditus Lugo-Ortiz and McCafferty, Procloeon Bengtsson, and Siph-lonurus Eaton are also reported from Alaska for the first time. The fauna consists mainly of species with widespread general or western distributions in North America, but also includes 1 1 confirmed Holarctic species. Rhithrogena ingalik, new species, is described from male adults; it differs from other congeners in genitalia morphology and is most closely related to certain Siberian species. Key Words: Alaska, Ephemeroptera, mayflies, Rhithrogena ingalik, new species, new records Because of concerns of global warming of Arctic and alpine habitats and the poten-tial impacts on those ecosystems (Chapin and Korner 1994), it is important that doc-umentation of the organisms within those regions be completed. Studies of ecosys-tems of low diversity, such as those found in the Arctic, may provide a ready means of understanding these systems and any changes they may undergo (Danks 1981, Chapin and Korner 1994, Poff et al. 2001). In addition, such data may be valuable for understanding historical biogeography in-volving circumpolar species. Considerable recent work has contributed to the documentation of the Ephemeroptera fauna of far northern North America (e.g.. Harper and Harper 1981, 1997; McCafferty 1985, 1994, McCafferty and Randolph 1998, Alba-Tercedor and McCafferty 2000, Randolph and McCafferty 2000). Species distributional data for certain subregions of the North had not been readily available previously and as a result faunal data have remained fragmentary, making any ecolog-ical or biogeographic assessments difficult (Harper and Harper 1997). For example, of the 63 species reported from the combined subregions of Alaska, Yukon, Northwest Territories, and Nunavut, relatively few have been known from Alaska (McCafferty 1985, 1994; Zloty 1996; Lee and Hershey 2000). A more complete documentation of Alaska is critical for hypothesizing Berin-gia's role in mayfly dispersal during the Pleistocene (see Hofle et al. 1994, Elias et al. 2000), and the possible role of Alaska in providing historical refugia in its ungla-ciated areas (McCafferty 1985, Elias et al. 2000). Herein we provide new state records for 27 species and 71 new county records for 39 of the 46 species we document from Alaska. This includes a new species of
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