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Not a fly - Isoperla transmarina

Not a fly - Isoperla transmarina
47.63054N 52.68758W (WGS84), Logy Bay, Northeast Avalon, Newfoundland/Labrador, Canada
July 9, 2008
Size: 11mm head to wing tips
Based on the wings, I'm going to say this is not a fly. Other that that, I'm stumped. I found this 'bug' sitting on our driveway. I couldn't photograph it immediately so I put it in a container and later released it on to some gray cardboard for the photograph. It was reluctant to fly. When the photos were done, I finally had to shake the cardboard to get it to fly away. It flew eratically and quickly landed on some grass.

Images of this individual: tag all
Not a fly - Isoperla transmarina Not a fly - Isoperla transmarina Not a fly - Isoperla transmarina Not a fly - Isoperla transmarina


Another possibility: Isoperla transmarina (?)
I stumbled upon what I believe is Banks' original description of Isoperla ventralis, collected from Grand Lake, NF. The size is exactly the same (11mm) and the description also seems to fit this specimen well. Isoperla ventralis is a junior synonym of Isoperla transmarina. Just a thought.

PS--I just found some images identified as transmarina for comparison: 1, 2.

could be
I photographed an Isogen. hansoni adult (posted at DiscoverLife) this summer, and it is certainly not this species based on color pattern and larger size. Based on size an Isoperla is verrry likely. I transmarina larvae are reasonably frequent in some of the streams here, so perhaps Tom or I will get lucky one of these days.

Lloyd Gonzales comment:
I believe this is probably Isoperla transmarina.

Moved from Stoneflies.

Perlodidae: Isogenoides hansoni
Checked the description of I. hansoni in the recent revision of this genus, and it fits your specimen well (and is very similar by the description to D. nan*seni), plus this species is known from Newfoundland.

I wish...
that I could live up to v belov's expectation and say something "authoritative" about this one, but I can't even improve upon the guess that this might be a perlid. I checked collection records for NF/LB and found no joy there. You surely must have more Plecoptera than have been recorded! I saw only one perlid listed (for NF, none for LB), and I'm pretty sure that this isn't it. None of the listed perlodids or chloroperlids rang any bells either, but I'm not familiar with of all of them.

Even though your photos are excellent, they don't show the areas that would allow for more definitive sorting. The presence of shriveled gill remnants on the sides of the thorax is one of the easier ways to determine a perlid ID, and clear detail of the anal region of the wing (that area close to the "shoulder") would help as well. However, these areas are rarely shown in a useful way in most photos of adult stoneflies. Sorry I couldn't be of more help with this one. :(

Thank you
I've added another image that I think shows one of the areas you mentioned as important. Is this of any use?

look among stoneflies

I went through all the stone flies and couldn't find one exactly like this one. I agree that the family Perlidae looks the closest but I wasn't confident enoguh to move the images there unless you think I should.

i'd recommend
...for you to wait for a more authoritative opinion -- there are people around here (Donald S. Chandler, Lloyd Gonzales) who seem to be well-versed in aquatic insects and review relevant posts every now and then; let them handle this

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