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 a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
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I'm guessing this specimen is in the genus Acerpenna because of the very sharp costal process on her hind wing. I'm guessing pygmaea because it is the most common species.
Editor note: Not Acerpenna. This is most likely Baetis. See comments on this male specimen for rationale. Also compare with the female specimen associated with it.
Editor note: Not Acerpenna. This is most likely Baetis. See comments on this male specimen for rationale. Also compare with the female specimen associated with it.
Troutnut on Jul 2, 2006July 2nd, 2006, 3:20 am EDT
How come?
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
Troutnut and salmonid ecologist
Taxon on Jul 6, 2006July 6th, 2006, 6:45 am EDT
Jason-
Oh, sorry. Just discovered your response. Because of the striking similarity of your specimen's fore wing venation to the that of Baetis brunneicolor portrayed in Leonard & Leonard, page 87, Fig. 51.
Here is your photo arranged for comparison purposes:
Oh, sorry. Just discovered your response. Because of the striking similarity of your specimen's fore wing venation to the that of Baetis brunneicolor portrayed in Leonard & Leonard, page 87, Fig. 51.
Here is your photo arranged for comparison purposes:
Troutnut on Jul 6, 2006July 6th, 2006, 7:25 am EDT
Ok, thanks. I just looked at Leonard and you're right that the venation is strikingly similar (though not identical). They don't have very many other Baetis wings to compare to, though, so I'm hesitant to rule out the other species on those grounds.
The costal process on the hind wing is much sharper in this specimen than in the Leondards' drawing. I think that's a fairly important characteristic for this family and it's one reason I'm hesitant to call it Baetis.
Also, the Leonards show some intercalary veins on the hind wings of brunneicolor, which I don't see in this photo. That could be due to individual variation or bad focus in the photo, though.
The taxonomy of this whole family is such a mess right now. I really hope somebody publishes a definitive key to the genera soon based on something better than mandible setae and the like.
The costal process on the hind wing is much sharper in this specimen than in the Leondards' drawing. I think that's a fairly important characteristic for this family and it's one reason I'm hesitant to call it Baetis.
Also, the Leonards show some intercalary veins on the hind wings of brunneicolor, which I don't see in this photo. That could be due to individual variation or bad focus in the photo, though.
The taxonomy of this whole family is such a mess right now. I really hope somebody publishes a definitive key to the genera soon based on something better than mandible setae and the like.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
Troutnut and salmonid ecologist
Troutnut on Sep 21, 2006September 21st, 2006, 5:28 pm EDT
I'm even more confident that this is Acerpenna now that I've photographed an extremely similar specimen from upstate NY. The new female was associated with a male which I also photographed, and it keyed fairly confidently to Acerpenna in Merritt & Cummins.
I've fallen a bit behind on posting new pictures I've taken. I've got about 30 new specimens to put up, I think, including the Acerpenna pair. All that's coming ASAP.
I've fallen a bit behind on posting new pictures I've taken. I've got about 30 new specimens to put up, I think, including the Acerpenna pair. All that's coming ASAP.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
Troutnut and salmonid ecologist
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