Keyed to genus using Merritt, Cummins and Berg (2008). There are four species of Centroptilum recorded in California: C. album, C. asperatum, C. bifurcatum and C. conturbatum. All are recorded from the Russian River or it's tributaries. I've collected both nymphs and adults near Healdsburg and in the area I've collected from there appears to be only one species. I was able to eliminate C. album and C. conturbatum as both nymphs and adults using "Lowen, Robert G. and John F. Flannagan – Four Manitoba Species of Centroptilum Eaton (Ephemeroptera: Baetidae) With Remarks on the Genus (1991)" and "Webb, M. W. – The Mayflies of Sasketchewan. Thesis. University of Saskatchewan (2002)." The nymphs of C. asperatum are not described but I was able to exclude adult males using "Needham, Traver and Hsu - The Biology of Mayflies (1935). In addition, BOLD SYSTEMS has several photos of C. bifurcatum nymphs showing the dorsal patterning and they appear to match specimens I've collected. They can be seen at http://www.boldsystems.org/index.php/Public_SearchTerms?query=%22Centroptilum%20bifurcatum%22[tax]. More photos of C. bifurcatum nymphs can be seen in in bugguide at
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Contributed by
Mark Melton on 29 March, 2014 - 8:19pm
Last updated 14 July, 2014 - 11:24pm