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Ephemeroptera: Heptageniidae of Gunnison County, Colorado

Ecdyonurus (Nixe) criddlei
Criddle's Flat-headed Mayfly, Western Ginger Quills

(McDunnough) 1927

Updated 18 Dec 2018
TSN 100693


Recently, in 2004, McCafferty changed this animal's name from Nixe criddlei to Ecdyonurus criddlei. There are many references to Nixe criddlei and the older name Heptagenia criddlei in species lists and the literature of the late 20th century.

Locations Collected

E. criddlei is found across Western Canada and the Western United States down to northern Mexico.

Good Links

On this website:
Nixe criddlei

Other Websites:
Photos, Map, Museum specimens, DNA - Barcodinglife.org

Photos and more from Troutnut


Argyle,DW and Edmunds,GF 1962 Mayflies (Ephemeroptera) of the Curecanti Reservoir Basins Gunnison River, Colorado. University of Utah Anthropological Papers 59 (8) 178-189.
     Discussed as Heptagenia criddlei.

Bedarik,AF and Edmunds,GF 1980 Descriptions of larval Heptagenia from the Rocky Mountain region (Ephemeroptera: Heptageniidae). Pan-Pacific Entomologist (56) 51-62. PDF
     Discussed as Heptagenia criddlei. Shows this species is present in Gunnison County.

Colletti,PJ; Blinn,DW; Pickart,A and Wagner,VT 1987 Influence of different densities of the mayfly grazer Heptagenia criddlei on lotic diatom communities. Journal of the North American Benthological Society 6(4):270-280. PDF

McCafferty,WP 2004 Contribution to the systematics of Leucrocuta, Nixe, and related genera (Ephemeroptera: Heptageniidae). Transactions of the American Entomological Society 130(1): 1-9.
     The author moves Nixe criddlei into the genus Ecdyonurus because it has all the features of the Ecdyonurus simplicioides species group. Quote from page 3: "For the purposes of recognizing Ecdyonurus in North America, i.e., the simplicioides species group of Ecdyonurus, especially from the closely related genera Leucrocuta and Nixe, it may be diagnosed as having generally plesiotypic larvae with well-developed male eyes, an unmodified pronotum, a gill tuft with two or more filaments present at base of gill lamellae 6 (usually well-developed), and the three caudal filaments with well-developed interfacing setae; and in adults, as having proximate male eyes in addition to having penes (e.g., Fig 98 [Traver 1935], Fig. 4g [Demoulin 1964], Figs 103, 106 ;Jensen 1966]) with divergent lobes that have spines present ventrally, a medially extended lateral sclerite dorsally, narrowly attenuate titillators, and that lack developed dorsolateral spines."   He notes that the genera Ecdyonurus, Leucrocuta and Nixe are very similar.

McCafferty,WP; Durfee,RS and Kondratieff,BC 1993 Colorado mayflies (Ephemeroptera): an annotated inventory. Southwestern Naturalist 38 3, 252-274. PDF
     Discusses this species as Nixe criddlei. Quote from page 261: "It is likely that some of the Heptagenia spp. reported from the upper Gunnison River drainage system by Argyle and Edmunds (1962) are referable to this species."

McCafferty,WP and Provonsha, AV The Mayflies of North AmericaSpecies List (Version 8Feb2011)
     Here is the geographic range and synonyms:
Ecdyonurus criddlei (McDunnough), 1927 [CAN:NW;MEX:SW;USA:NW,SW]
    * Ecdyonurus otiosus (McDunnough), 1935 (syn.)
    * Ecdyonurus rosea (Traver), 1935 (syn.)
    * Ecdyonurus salvini (Kimmins), 1934 (syn.)
    * Heptagenia criddlei McDunnough, 1927 (orig.)
    * Heptagenia otiosa McDunnough, 1935 (syn.)
    * Heptagenia rosea Traver, 1935 (syn.)
    * Heptagenia rubroventris Traver, 1935 (syn.)
    * Heptagenia salvini Kimmins, 1934 (syn.)
    * Nixe criddlei (McDunnough), 1927 (comb.)
    * Nixe otiosa (McDunnough), 1935 (syn.)
    * Nixe rosea (Traver), 1935 (syn.)
    * Nixe salvini (Kimmins), 1934 (syn.)

McDunnough,J 1927 A new Heptagenia from the Yellowstone Region (Ephemeroptera). Canadian Entomologist 59:261.
     Described as Heptagenia criddlei

Moody,EK; Corman,JR and Bogan,MT 2016 Caught between a rock and a hard mineral encrustation: long-lived aquatic insects accumulate calcium carbonate deposits in a montane desert stream. Western North American Naturalist, 76(2), 172-179. PDF
     Quote from page 177:"Long-lived species that go through many larval instars may be less likely to accumulate CaCO3 encrustation due to their higher molting frequency. Of the aquatic insects, mayflies tend to have particularly high numbers of larval instars (Fink 1980), but only one long-lived mayfly was represented in our stream: Ecdyonurus criddlei. Although the life history of E. criddlei has not been studied, congeneric species pass through at least 18 larval instars (Rawlinson 1939). This high molting frequency might explain why we never found Ecdyonurus with CaCO3 deposits. "

Zuellig,RE; Kondratieff,BC; Rhodes,HA 2002 Benthos recovery after an episodic sediment release into a Colorado Rocky Mountain river. Western North American Naturalist 62 (1) 59-72.
     Discusses this species as Nixe criddlei.

Brown,WS 2004 Mayflies (Ephemeroptera) of Gunnison County, Colorado, USA