Ephemeroptera: Heptageniidae of Gunnison County, ColoradoIntroduction to the mayfly genus Rhithrogena
Red Quills, Western March BrownsEaton 1881
Updated 2 Feb 2012
TSN 100572
The recently emerged Rhithrogena female subimago or dun was photographed in the Cement Creek drainage on 21July2008. This animal will molt once more to become a sexually mature imago.
Species List
References
Allen,RK; Chao,ESM 1978 Mayflies of the Southwest: new species and records of Heptageniidae. Pan-Pacific Entomologist 54, 311-315.
Brinkman,SF and Johnston,WD 2008 Acute toxicity of aqueous copper, cadmium, and zinc to the mayfly Rhithrogena hageni. Archives of Environmental Contamination and Toxicology 54:3, 466-472. Abstract
Buchwalter,DB; Cain,DJ; Martin,CA; Xie,L; Luoma,SN; Garland,JT 2008 Aquatic insect ecophysiological traits reveal phylogenetically based differences in dissolved cadmium susceptibility. Proceedings of the National Academy of Sciences 105 24, 8321-8326.
Dodds,GS 1923 Mayflies from Colorado: descriptions of certain species and notes on others. Transactions of American Entomological Society 69, 93-116.
Durfee RS; Kondratieff BC. 1994 New additions to the inventory of Colorado mayflies (Ephemeroptera). Entomological News 105(4):222-227. PDF
Quote from page 223: "The adults of R. pellicuda can easily be separated from the other four species of Rhithrogena in Colorado by their distinctive genitalia (Fig. 1) and small size. The larvae of R. pellicuda can be separated from the other species of Colorado Rhithrogena by the absence of a dorsal lobe on gills 2-6 (present on R. hageni Eaton, and R. undulata [Banks]), and the absence of a longitudinal ventral sclerotized setose line on gills 2-6 (present on Rhithrogena robusta Dodds) (Jensen 1966). In addition, the larvae of R. pellicuda have a characteristic V-shaped transparent marking on the ventral gill surface that points out perpendicular to the long axis of the body. Although the larvae of R. flavianula are unknown, the much larger size of the adults (body length 14mm) (McDunnough 1924), should make mature larvae of this species easily separable from the much smaller R. pellicuda (body length 6-7mm). "
Eaton AE. 1881 An announcement of new genera of the Ephemeridae. Entomologist's Monthly Magazine 18:21-27.
The genus Rhithrogena is described on pages 23 and 24.
Edmunds GF Jr. 1952b Studies on the Ephemeroptera. Part II. The taxonomy and biology of the mayflies of Utah
Unpublished Ph.D. Thesis, University of Massachusetts 399 pages.
Jensen,SL 1966 The Mayflies of Idaho (Ephemeroptera). M.S. Thesis, University of Utah, Utah. 364 p.
Quote from page 188: "The following combinations of characters serve to distinguish this genus from all other genera of Heptageniidae occuring in Idaho: Adults. (1) Basal segment of the fore-tarsi of the male one fourth or less as long as the second segment; (2) stigmatic crossveins more or less anastomosed (Fig. 72), or if only slighty anastomosed, the femora have a dark streak of color present; and (3) subanal plate of the female broadly rounded, without a postero-median emargination. Mature nymphs. (1) Three well developed caudal filaments; and (2) gills on abdominal seggments one and seven enlarged, meeting beneath the abdomen to form a ventral disc (Fig 83). "
Stanford JA; Gaufin AR. 1974 Hyporheic communities of two Montana rivers. Science 185:700-702. PDF
The authors report Rhithrogena nymphs from the hyporheic zone of the Flathead River in Montana, USA.
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