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3. A Mayfly ID requested

Hello,
I am angler from BC and enjoy, as an angler and artist, all the info on your site, Jason.
This past weekend I was fishing on the Skagit River above Ross Lake and was introduced to a wee olive winged mayfly that I have not been able to identify. Perhaps someone on this board can help me out.
Here is a photo:

Thanks,
Fran

I thought it looked a bit like Epeorus, too, but it's much skinnier than the ones I'm used to seeing. I'm just not sure what else it would be.

Fran emailed me an additional detail, this mayfly usually emerges in September and can be fairly important there, but it's running a bit late this year and emerging more recently.

Fran -

Welcome to the forum!

This is a female subimago (dun) most likely of the family Heptageniidae (Flat-headed Clinger nymphs). Since you mention that they are abundant and important, two common species of heptageniid this size come to mind as possible matches one would expect to see this time of year. One is Epeorus albertae (Western Gordon or a plethora of "pink" names) and the other is Cinygmula reticulata (Western Red Quill).

The general coloring, conformation, and markings are a pretty good match for reticulata, but it is far less common. The female Gordons (albertae) I've seen over the years are either much paler than this (usually with a lot of yellow and/or pink) or are an olivaceous gray. Also the dark ones have gray wings without the pastel wash this noticeable. Both variations of albertae also usually (but not always) have marked legs as well as paler tails than this specimen. But, I haven't seen 'em all!:)

I'd like to know more about the habitat as generally speaking low altitude big water favors albertae (though latitude may have an impact on this generalization).


Sorry to disappoint, Mack.:) The only thing I'm reasonably confident in at this point is that it's probably a heptageniid, though there are some ameletids that are closer to the look of this gal's conformation in some respects and females are tough. The critter's in shadow and it's hard to make out much morphological detail. Now, if I could get a good look at the wing venation, face, subanal plate, and tarsi...:)


Agreed Jason, with the caveat that camera angles often mislead me. This is another character a little off.

This one really intrigues me. Notice what appears to be a pair of small projections on the corners of the mesoscutum at the anterior margin? Also, what appears to be a relatively straight posterior head margin between the eyes instead of the highly concave shape one would expect to see? These aren't very Epeorus-like characters either. The bottom line is these characters have me vexed. Hopefully, somebody else can help with possible explanations before I have time to think on it a little more...

Which one, Mack?

BTW - another important character for indicating E. albertae is the presence of a dark and thickened humeral vein that should clearly stand out from the costal cross veins - not seeing it here. Also, the presence of a transverse suture on the mesonotum (assuming the apparent projections are actually just highlighted corners of the ridge) rules out species of the genus Epeorus.

Thanks to you all for helping me out here. Interesting discourse. I wish I had got a sharper image before it flew away. I have put out a request to an angler headed up to the Skagit this weekend to see if he can get a better one. But it is supposed to rain all weekend and the hatch may not happen as it did on the sunny day I was there.
The quest continues :-)
fran

Hi Fran,


Ha! That should be the title of our theme song.:) The truth is yours is a fine photo for an "off the cuffer" taken by an angler whose primary focus at the time was... Fishing? :) Phrases like "can't make this out" or "wished I could see" aren't meant as complaints against the photo but are rather explanations/excuses for not being able to help more definitively!:)

Thanks for submitting the specimen!

Best regards,

Kurt

P.S. - As for "continuing the quest", check this out http://www.troutnut.com/specimen/963. I think you can be reasonably comfortable with Cinygmula at this point.

HI Kurt,
Not miffed with the comments, was just a fact that the photo is not crisp. I have done better but sometimes the bug is in control :-)

Considering the Cinygmula given color variations possible it looks pretty close to me too. It has the lighter banding on the body, the lighter almost clear legs, the darker thorax. The color of the thorax had that dark green iridescent bug color.

Here is a photo of the river which has fast runs and gentle runs and deeper pools. Very pretty river I don't get to fish nearly often enough.



fran

Ah... That's definitely the right looking habitat. I feel even better about Cinygmula.:) Thanks for the photo!


Yes, especially the wings. I've seen them from canary yellow to dull gray... To this point, I've been unable to verify if this character (the amount of pastel infusion) indicates specific differentiation.