Salmonflies
Pteronarcys californica
The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
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This is an interesting one. Following the keys in Merritt R.W., Cummins, K.W., and Berg, M.B. (2019) and Jacobus et al. (2014), it keys clearly to Ephemerella. Jacobus et al provide a key to species, but some of the characteristics are tricky to interpret without illustrations. If I didn't make any mistakes, this one keys to Ephemerella mucronata, which has not previously been reported any closer to here than Montana and Alberta. The main character seems to fit well: "Abdominal terga with prominent, paired, subparallel, spiculate ridges." Several illustrations or descriptions of this holarctic species from the US and Europe seem to match, including the body length, tarsal claws and denticles, labial palp, and gill shapes. These sources include including Richard Allen's original description of this species in North America under the now-defunct name E. moffatae in Allen RK (1977) and the figures in this description of the species in Italy.
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Isogenoides hansoni (Appalachian Springfly) Stonefly Nymph Pictures
This large Perlodidae stonefly was a strikingly bright yellow color, more so than any other insect I've seen. I didn't enhance it much. See the discussion threads to follow how we identified this specimen, which was listed incorrectly for several years.
This stonefly was collected from Mongaup Creek in New York on April 19th, 2006 and added to Troutnut.com by Troutnut on April 21st, 2006.
Discussions of this Nymph
Arcynopteryx
3 replies
Posted by Taxon on Jul 7, 2006
Last reply on Nov 9, 2011 by Entoman
Jason-
Not to despair; this is what American Stoneflies: A Photographic Guide to the Plecoptera by Bill P. Stark, Stanley W. Szezytko, and C. Ridley Nelson has to say about genus Arcynopteryx:
"This genus is represented in North America by A. compacta (McLachlan). This species ranges from Alaska to Maine and has been reported as far south as Colorado. Males usually have shortened wings and are easily recognized by the long, lash-like epiproct tip. Females and nymphs are quite similar to Skwala. A. compacta has been collected around alpine lakes in the northern Rocky Mountains. No photographs are available for this group."
Also, Arcynopteryx compacta is listed by Stark/Baumann as residing in New York.
Not to despair; this is what American Stoneflies: A Photographic Guide to the Plecoptera by Bill P. Stark, Stanley W. Szezytko, and C. Ridley Nelson has to say about genus Arcynopteryx:
"This genus is represented in North America by A. compacta (McLachlan). This species ranges from Alaska to Maine and has been reported as far south as Colorado. Males usually have shortened wings and are easily recognized by the long, lash-like epiproct tip. Females and nymphs are quite similar to Skwala. A. compacta has been collected around alpine lakes in the northern Rocky Mountains. No photographs are available for this group."
Also, Arcynopteryx compacta is listed by Stark/Baumann as residing in New York.
I. hansoni
Posted by GONZO on Oct 3, 2010
Last reply on Oct 3, 2010 by GONZO
I believe that this is actually Isogenoides hansoni. When Dr. Chandler and Luke Myers made earlier "Cultus" comments on this specimen, they seem to have missed the prominent submental gills shown in photo #5 (and #7).
In addition to the submental gills (more than 2X as long as wide), the pale area on the 10th tergum, the distinct enclosed pale "M" mark on the head, and (often) the elongated pale spot in the center of the head are a few of the distinctive traits of this species. A complete description and a depiction of the dorsal habitus (figure #88) can be found in Sandberg and Stewart (Holomorphology and Systematics of the Stonefly Genus Isogeniodes, 2005).
The type specimens of I. hansoni were collected from my old homewaters on the Brodheads in 1937 by Preston Jennings (the author of the classic A Book of Trout Flies).
Cultus verticalis is a smaller, pale yellowish nymph, typically with a bolder, simpler dorsal pattern and less intricate markings on the dorsal surface of the head/thorax.
In addition to the submental gills (more than 2X as long as wide), the pale area on the 10th tergum, the distinct enclosed pale "M" mark on the head, and (often) the elongated pale spot in the center of the head are a few of the distinctive traits of this species. A complete description and a depiction of the dorsal habitus (figure #88) can be found in Sandberg and Stewart (Holomorphology and Systematics of the Stonefly Genus Isogeniodes, 2005).
The type specimens of I. hansoni were collected from my old homewaters on the Brodheads in 1937 by Preston Jennings (the author of the classic A Book of Trout Flies).
Cultus verticalis is a smaller, pale yellowish nymph, typically with a bolder, simpler dorsal pattern and less intricate markings on the dorsal surface of the head/thorax.
Anybody know the genus and species?
8 replies
Posted by Troutnut on Jul 7, 2006
Last reply on Feb 12, 2009 by Troutnut
This stonefly comes from a fertile, cold small stream in the Catskills. I tried to ID it using the key to genera in Merritt & Cummins but I ended up with a fairly confident identification that can't be correct: Arcynopteryx, a western mountain genus. So I'm stuck at couplet 89 in the M&C key.
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References
- Jacobus, L. M., Wiersema, N.A., and Webb, J.M. 2014. Identification of Far Northern and Western North American Mayfly Larvae (Insecta: Ephemeroptera), North of Mexico; Version 2. Joint Aquatic Science meeting, Portland, OR. Unpublished workshop manual. 1-176.
- Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.
Isogenoides hansoni (Appalachian Springfly) Stonefly Nymph Pictures
Collection details
Location: Mongaup Creek, New York
Date: April 19th, 2006
Added to site: April 21st, 2006
Author: Troutnut
Date: April 19th, 2006
Added to site: April 21st, 2006
Author: Troutnut