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Stoneflies - Plecoptera: Capniidae of Gunnison County, Colorado

Capnia gracilaria
Slender Snowfly, Winter Stonefly

Claassen 1924
Updated 14 March 2021
TSN 102712

Locations Collected

South Fork Gunnison River Drainage about 7000 to 8400 feet elevation (Knight and Gaufin 1966).


Nelson and Baumann (1989) placed C. gracilaria in the Gracilaria Group. They noted C. gracilaria is "often the dominant capniid in streams of their range" and provide a species description on page 324.

Good Links

On this website:
Capniidae Introduction
Capnia Introduction

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

Photos from the Web of Life
Adult or Nymph


Claassen,PW 1924 New species of North American Capniidae (Plecoptera). Canadian Entomologist 56, 43-48, 54-57. Type specimen

Knight,AW; Gaufin,AR 1966 Altitudinal distribution of stoneflies (Plecoptera) in a Rocky Mountain drainage system. Journal of the Kansas Entomological Society 39 4, 668-675.

Kondratieff,BC and Baumann,RW 2002 A review of the stoneflies of Colorado with description of a new species of Capnia (Plecoptera: Capniidae). Transactions of American Entomological Society 128 3, 385-401.
     Quote from page 388: " Capnia gracilaria is another common winter stonefly of streams and small river throughout the Mountain and Plateau regions of Colorado (Baumann et al 1977, Nelson and Baumann 1989)."

Needham,JG and Claassen,PW 1925 A Monograph of the Plecoptera of North America. Entomological Society of America, Lafayette, Indiana. 397 pages.

Nelson,RC; Baumann,RW 1989 Systematics and distribution of the winter stonefly genus Capnia (Plecoptera: Capniidae) in North America. Great Basin Naturalist 49, 289-363.

Young,MK; Smith,RJ; Pilgrim,KL; Fairchild,MP and Schwartz,MK 2019 Integrative taxonomy refutes a species hypothesis: The asymmetric hybrid origin of Arsapnia arapahoe (Plecoptera, Capniidae). Ecology and evolution, 9(3), pp.1364-1377. PDF
     Abstract: "Molecular tools are commonly directed at refining taxonomies and the species that constitute their fundamental units. This has been especially insightful for groups for which species hypotheses are ambiguous and have largely been based on morphological differences between certain life stages or sexes, and has added importance when taxa are a focus of conservation efforts. Here, we examine the taxonomic status of Arsapnia arapahoe, a winter stonefly in the family Capniidae that is a species of conservation concern because of its limited abundance and restricted range in northern Colorado, USA. Phylogenetic analyses of sequences of mitochondrial and nuclear genes of this and other capniid stoneflies from this region and elsewhere in western North America indicated extensive haplotype sharing, limited genetic differences, and a lack of reciprocal monophyly between A. arapahoe and the sympatric A. decepta, despite distinctive and consistent morphological differences in the sexual apparatus of males of both species. Analyses of autosomal and sex-linked single nucleotide polymorphisms detected using genotyping by sequencing indicated that all individuals of A. arapahoe consisted of F1 hybrids between female A. decepta and males of another sympatric stonefly, Capnia gracilaria. Rather than constitute a self-sustaining evolutionary lineage, A. arapahoe appears to represent the product of nonintrogressive hybridization in the limited area of syntopy between two widely distributed taxa. This offers a cautionary tale for taxonomists and conservation biologists working on the less-studied components of the global fauna."

Brown,WS 2004 Stoneflies of Gunnison County, Colorado