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Ephemeroptera: Ephemerellidae of Gunnison County, Colorado

Introduction to the Mayfly genus Ephemerella
Pale Morning Dun, PMDs, Pale Morning Olive, Pale Morning Spinner, Pale Olive Quill

Walsh 1862
Updated 20 Jun 2020
TSN 101233

Provisional Species List

Ephemerella aurivillii
Ephemerella excrucians (inermis)
Ephemerella dorothea infrequens


This genus has many lovely translucent little yellow species. The taxonomy has been changing recently, but no matter, the fishermen recognize the local species of Pale Morning Dun in streams across our planet.

Good Links

On this website:
Ephemerella apopsis
Ephemerella inermis
Introduction to Ephemerellidae

Other Websites:
Photo Adult male - go to the bottom of the page and among many great photos, there is a Pale Morning Dun or Ephemerella dorothea second from the right.


Alexander,LC; Delion,M; Hawthorne,DJ; Lamp,WO and Funk,DH 2009 Mitochondrial lineages and DNA barcoding of closely related species in the mayfly genus Ephemerella (Ephemeroptera: Ephemerellidae). Journal of the North American Benthological Society, 28(3) 584-595. PDF
     Abstract: "We compared genetic lineages in the mayfly genus Ephemerella (Ephemeroptera: Ephemerellidae) identified from mitochondrial DNA (mtDNA) to current taxonomy in 9 morphological taxa, including 2 geographically widespread species, Ephemerella invaria ( = E. inconstans, E. rotunda, E. floripara) and Ephemerella dorothea ( = E. infrequens). Maximum likelihood and parsimony analyses of the mtDNA sequences placed E. inconstans and E. invaria in a well-supported clade; however, mean Kimura 2-parameter genetic distance between the lineages was high (5.2%) relative to distance within lineages (1.3%). The phylogenetic relationships of synonyms E. rotunda and E. floripara were not resolved, but estimates of mean genetic distance to E. invaria were high for both (8.5% and 11.6%, respectively). Populations of E. dorothea were grouped in 2 well-supported clades (12.9% mean divergence) that did not include the synonym E. infrequens (20.9% mean divergence, based on a single sample). A large genetic distance (18.6%) also was found between eastern and western populations of Ephemerella excrucians. Western samples of Ephemerella aurivillii were so genetically distant from all other lineages (32.2%) that doubt about its congeneric status is raised. mtDNA data have been useful for identifying genetic lineages in Ephemerella, but our results do not support use of cytochrome oxidase I (COI) as a DNA barcode to identify species in this genus because we also found evidence of incomplete mtDNA lineage sorting in this gene. Use of the barcoding gene rediscovered some old taxonomic problems in Ephemerella, a result that emphasizes the importance of completing empirical systematic description of species before using single-character systems for identification."

Allen,RK 1968 New species and records of Ephemerella (Ephemerella) in western North America (Ephemeroptera: Ephemerellidae). Journal of the Kansas Entomological Society 41(4):557-567 PDF

Brinkman,SF and Johnston,WD 2012 Acute toxicity of zinc to several aquatic species native to the Rocky Mountains. Archives of environmental contamination and toxicology, 62(2), 272-281.

Gill,BA; Harrington,RA; Kondratieff,BC; Zamudio,KR; Poff,NL and Funk,WC 2014 Morphological taxonomy, DNA barcoding, and species diversity in southern Rocky Mountain headwater streams. Freshwater Science 33(1) 288-301.
     Working in wadeable streams on the Front Range of Colorado, they found a cryptic species of Ephemerella alongside E. dorothea and infrequens.

Jacobus,LM and McCafferty,WP 2003 Revisionary contributions to North American Ephemerella and Serratella (Ephemeroptera: Ephemerellidae). Journal of the New York Entomological Society 111:174-193. PDF
     This paper reorganized the taxonomy map for the genus Ephemerella.

Jacobus, LM and McCafferty, WP 2008 Revision of Ephemerellidae genera (Ephemeroptera). Transactions of the American Entomological Society 134: 185-274. PDF
     Abstract: "The study of population variability and the reexamination of type material of certain Ephemerellidae species has revealed changes in status and new synonyms. Ephemerella dorothea Needham, 1908 [=E. infrequens McDunnough, 1924, new synonym, =E. mollitia Seemann, 1927, new synonym] is divided into two subspecies: E. d. dorothea, new status, and E. d. infrequens new status [=E. mollitia, new synonym]. New synonyms were discovered for the following: Ephemerella excrucians Walsh, 1862 [=E. inermis Eaton, 1884, new synonym, =E. argo Burks, 1947, new synonym, =E. crenula Allen and Edmunds, 1965, new synonym, =E. lacustris Allen and Edmunds, 1965, new synonym, =E. rossi Allen and Edmunds, 1965, new synonym, =E. rama Allen, 1968, new synonym], E. invaria Walker, 1853 [=E. rotunda Morgan, 1911, new synonym, =E. vernalis Banks, 1914, new synonym, =E. feminina Needham, 1924, new synonym, =E. fratercula McDunnough, 1925, new synonym, =E. inconstans Traver, 1932, new synonym, =E. choctawhatchee Berner, 1946, new synonym, =E. simila Allen and Edmunds, 1965, new synonym, =E. floripara McCafferty, 1985, new synonym], E. mucronata (Bengtsson), 1909 [=E. moffatae Allen, 1977, new synonym], Serratella micheneri (Traver), 1934 [=E. altana Allen, 1968, new synonym], S. serrata (Morgan), 1911 [=S. sordida (McDunnough), 1925, new synonym, =S. carolina (Berner and Allen), 1961, new synonym, =S. spiculosa (Berner and Allen), 1961, new synonym], and S. tibialis."

Short,RA; Canton,SP and Ward,JV 1980 Detrital processing and associated macroinvertebrates in a Colorado mountain stream. Ecology, 61(4), 727-732. PDF

Walley GS. 1930. Review of Ephemerella nymphs of western North America (Ephemeroptera). Canadian Entomologist 62(1):12-20, pl. 2-3. PDF

Walsh, BD 1862 List of the Pseudoneuroptera of Illinois contained in the cabinet of the writer, with descriptions of over forty new species, with notes on their structural affinities. Proceedings of the Academy of Natural Sciences Philadelphia 14:361-402.
     Walsh described the genus Ephemerella in this paper.
Walsh 1862 decription of the mayfly genus Ephemerella

Williams,MC and Lichtwardt,RW 1999 Two new Harpellales living in Ephemeroptera nymphs in Colorado Rocky Mountain streams. Mycologia, 91(2) 400-404. PDF
     Abstract: "Two new species of harpellid gut fungi (Zygomycota: Trichomycetes) are described from the hindguts of mayfly nymphs inhabiting high altitude Rocky Mountain streams: the new genus and species Legeriosimilis tricaudata living in Ameletus sp. (Siphlonuridae), and the new species Glotzia coloradense from Baetis tricaudatus (Baetidae). Legeriomyces aenigmaticus is reported from a new site and a new ephemeropteran host, Ephemerella sp. (Ephemerellidae), and previously unknown zygospores are described."

"It ain't what you don't know that gets you into trouble.
It's what you know for sure that just ain't so."
--Mark Twain

Brown,WS 2009 Ephemeroptera of Gunnison County, Colorado