1. Troutnut Forum
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2. Specimen Discussion
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3. I'm pretty unsure about these IDs

I wish I had been able to get a male spinner for a positive ID. I wasn't able to collect any, unfortunately. The keys I have to the adult genera of the Ephemerellidae require one.

I've placed several specimens collected from a similar emergence on nearby rivers into the species Attenella attenuata, because they look exactly like the picture of that species in some books, most recently Ted Fauceglia's Mayflies. They are handy midday and early evening emergers in northwest Wisconsin at a time when not much else is on the water. But I'm not convinced that the identification is correct.

For one thing, although I tried sampling several times in stretches where the duns were emerging, the only mature Ephemerellid nymphs I found keyed out to Ephemerella inermis, which is now Ephemerella excrucians. These adults fit the general description for that widely variable species. I never found any Attenella nymphs.

I suspect they are the same species referred to in nearby parts of Wisconsin as "Kinni Sulphurs" and "Booger Sulphurs." As best I can tell from looking up those names, they seem to have been identified as Ephemerella inermis but there is a local belief that they are Ephemerella needhami, even though their color does not at all fit the description for that species.

Ah, to have a male spinner under the microscope...

Jason-

Don't see anything that would cause me to doubt that she's an Attenella imago. However, I'm curious why you are thinking A. attenuata, rather than A. margarita, given the olive abdomen.

In any event, I've heard you refer to Ted Fauceglia's book one too many times now. Guess I'm just going to have to give up and go buy one!

Fauceglia's book has some really great pictures, and they're the main reason I'd recommend buying it. They're the best I've seen in publication. They are accompanied by entomological information, but except for a few passages it's just material combined from other other major sources.

I haven't thought about whether it might be margarita or not, but attenuata is generally considered to be the most common eastern species.

I'm doubtful of the genus identification for a few reasons:

1. Attenella has a history of confusing people and getting credit for other hatches (like the eastern Drunella BWOs).

2. I couldn't find any Attenella nymphs, but I did find mature Ephemerella excrucians nymphs (keyed to synonymous inermis).

3. I know people who recognize the mayfly as a hatch called the "Kinni Sulphur" on a nearby river, which has been tentatively identified as E. inermis.

The main thing suggesting that it's attenuata is that it's a perfect match to published pictures of that species.

Jason,

Is there a species given more false credit in photos and angling lit? I think your suspicions that this specimen isn't A. attenuata are well founded. I agree that it is probably E. excrucians. Check out the photos and commentary in this topic: http://www.troutnut.com/topic/7808/2/-Male-Spinner-a-Female-Ephemerellid#35203

Another thing that's interesting (assuming it is indeed excrucians) is the fact that it is of the much paler inermis strain that is supposedly a western form with a disparate population in eastern Canada. The more commonly documented midwestern form (which is the species type) is brown bodied, darker winged, and also smaller than most paler forms. I can't place the topic, but I seem to remember you posted what appeared to be an excrucians (inermis) specimen of the pale form from the Catskill region of New York. It seams pretty clear that their ranges overlap more than was previously thought. I wonder if the two strains can be found together and without evidence of intergrades as well. If all of this is true, what does this mean to the current species concept? Is there a reinstatement or new subspecies in the offing?

I moved this specimen to excrucians as it is the most likely location based on current species concepts. Jason's nymph evidence mentioned in the thread provides the most compelling rationale. Professional comments on my previous post would be very helpful and appreciated.