Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Earlfishman on Apr 11, 2007April 11th, 2007, 5:20 pm EDT
I really enjoy your site, you've got some great photos and some really good info. I just wanted to let you know that this mayfly looks like it might actually be a Baetis sp., not a Diphetor hageni. Diphetor's antenna would be much closer together at the base and there would definitely be no gill on ab seg. 1. I can't give you a sure ID without photos of the front of the head and the mouth parts.
Troutnut on Apr 12, 2007April 12th, 2007, 5:53 pm EDT
Glad you like the site. I just re-traced my ID of this specimen in the keys in Merrit & Cummins, and I branch away from Baetis with this one at a couplet checking to see whether a femoral villopore is present. I can't see one on this specimen, so I followed a sequence which led to Diphetor. Perhaps my pictures aren't detailed enough with regard to that feature?
If this becomes really interesting, I can pick the specimen back out of the alcohol and check for that under a microscope. For now I'm going to take your "not Diphetor" ID and reclassify this one as an unknown Baetid.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
Earlfishman on Apr 13, 2007April 13th, 2007, 11:37 am EDT
The villipore is actually nearly impossible to see without a compound scope, I really don't like that character.
Keep in mind that when you get to that couplet, you are heading towards only 4 genera. Both Diphetor hageni and Fallceon quilleri have a distinct keel between the antennal bases and Diphetor has no gill on ab 1. Cloedes is seriously geographically restricted and Acerpenna has the pointy gill on seg 7 and a really thick terminal abdominal filament.