Ephemeroptera: Heptageniidae of Gunnison County, ColoradoHeptagenia elegantula
Dark Quill Gordon, Western yellow drake, Grey drake (Eaton) 1885
Updated 31 December 2025
TSN 100604
Good Links
On this website:
Heptagenia solitaria
Other Websites:
Photos, Map, Taxon Identifier Numbers - from the Global Biodiversity Information Facility Heptagenia elegantula at Gbif
Photos, Map, Museum specimens, DNA - Barcodinglife.org
References
Andrew,FB 1980 Mountain Region (Ephemeroptera: Heptageniidae). Pan-Pacific Entomologist, 56(1), pp.51-62. PDF
Bedarik,AF and Edmunds,GF 1980 Descriptions of larval Heptagenia from the Rocky Mountain region (Ephemeroptera: Heptageniidae). Pan-Pacific Entomologist (56) 51-62. PDF
Daggy,RH 1945 New species and previously undescribed naiads of some Minnesota mayflies (Ephemeroptera). Annals of the Entomological Society of America, 38(3), pp.373-396. PDF
Eaton,AE 1883-1888 A revisional monograph of recent Ephemeridae or mayflies. Transactions of the Linnean Society of London, Second Series, Zoology 3:1-352, 65 pl.
Described as Rhithrogena elegantula.
Edmunds Jr, GF 1995 Habitat differences between northern and southern populations of mayflies of the western United States. Pages 171-176 in Corkum LD; Ciborowski JJH. Current Directions in Research on Ephemeroptera. Canadian Scholars' Press, Inc. Toronto.
Gilpin,BR and Brusven,MA 1970 Food habits and ecology of mayflies of the St. Maries River in Idaho. Melanderia 4:19-40. PDF
Haden,GA; Blinn,DW; Shannon,JP and Wilson,JP 1999 Driftwood: an alternative habitat for macroinvertebrates in a large desert river. Hydrobiologia 397, 179-186. PDF
Abstract: "Driftwood was an important substratum for macroinvertebrates in the Colorado River, a desert river in southwestern U.S.A. with high suspended sediments and limited cobble substrata. Higher light availability and reduced abrasion on driftwood substrata resulted in a significantly higher ash-free dry mass (AFDM) of biofilm when compared to cobbles. Overall mean mass of biofilm on driftwood was 3.76 g m-2 AFDM (SE ±0.19) compared to 2.45 g m-2 AFDM (±0.15) on cobbles. Total macroinvertebrate AFDM was not significantly different between cobble and driftwood substrata. However, there were differences in the Ephemeroptera assemblage on the two substrata which were attributed to the type of food resources available in each habitat. Driftwood was dominated by the scraper/collector Heptagenia elegantula (Eaton), while the filterer/collector, Traverella albertana (McDunnough) dominated cobbles. Twenty taxa were found on driftwood substrata. This habitat expands the types of niches available to macroinvertebrates in lotic systems with high suspended sediments. We calculated that 4.4 m2 of driftwood substratum passed our sample station each minute during a 12-h sampling period on the rising limb of the hydrograph. River impoundments limit the supply and transport of driftwood, which may have negative implications on macroinvertebrate communities in desert rivers with high suspended sediment. Studies in turbid desert rivers that do not sample driftwood may underestimate both the total standing mass/energy of the system and taxon richness."
McCafferty,WP; Durfee,RS and Kondratieff,BC 1993 Colorado mayflies (Ephemeroptera): an annotated inventory. Southwestern Naturalist 38 3, 252-274. PDF
Quote from page "Larvae of H. elegantula can be difficult to distinguish from H. solitaria. See Bednarik and Edmunds (1980) for dorsal abdominal pattern variations in both species. Larvae tentatively identified as H. elegantula in CSU are from Grizzly Creek (Jackson Co.)"
They report specimens in the Purdue University Entomological Collection (PERC) from Iola in Gunnison County. Unfortunately now the ex-Gunnison River at the ex-town of Iola is usually under the water of Blue Mesa Reservoir.
Webb,JM and McCafferty,WP 2008 Heptageniidae of the world. Part II. Key to the genera. Canadian Journal of Arthropod Identification, 7(10.37551). PDF
Fig. 41 Heptagenia elegantula, apex of outer incisor of planate mandible.
Fig. 113, Heptagenia elegantula, egg chorion.
male penes. Figure 155 H. elegantula,
Webb,J; McCafferty,W and Lehmkuhl,D 2002 The larval stage of Heptagenia adaequata. Entomological News, 113(5), pp.289-293. PDF
Abstract: "Larvae of the poorly known western North American species Heptagenia adaequata are described for the first time based on material reared from the Saskatchewan River system. Diagnoses are provided for differentiating larvae of H. adaequata from other species of Heptagenia within its range, especially the common H. solitaria and H. elegantula, with which it might be confused."
Webb,JM; Sun,L; McCafferty,WP and Ferris,VR 2007 A new species and new synonym in Heptagenia Walsh (Ephemeroptera: Heptageniidae: Heptageniinae) based on molecular and morphological evidence. Journal of Insect Science, 7(1), p.63. Html
Last few sentences of the Abstract: "...Heptagenia diabasia Burks and H. elegantula (Eaton) differed from each other by only 1.1%; these two alleged species show a clinal pattern in larval abdominal coloration and there are no structural differences between the semaphorants. On this basis, H. diabasia is placed as a junior subjective synonym of H. elegantula, n.syn."
Zuellig,RE; Heinold,BD; Kondratieff,BC and Ruiter,DE 2012 Diversity and Distribution of Mayflies (Ephemeroptera), Stoneflies (Plecoptera), and Caddisflies (Trichoptera) of the South Platte River Basin, Colorado, Nebraska, and Wyoming, 1873-2010. U.S. Geological Survey Data Series 606, 257 p. PDF - caution 46MB
Quote from page 32: "Bednarik and Edmunds (1980) provided a key to the larvae and Webb and others (2007) placed Heptagenia diabasia Burks as a junior synonym of H. elegantula (Eaton). This synonymy bridges the eastern and western affinities of the previously separated species. This species can apparently tolerate siltation, low flows, variable water temperatures, and wide elevation ranges. McCafferty and others (1993) also reported records from Jefferson, Boulder, and Gilpin Counties." The elevation range is 9,950 2,850 feet and the adults emerge from June-September.
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