I've been collecting these Baetis
nymphs in the Russian River and don't have a clue as to what species they are. Any help would be appreciated.
I've labelled them species #1, #2 and #3. Species #1 and #3 may be the same as I've only collected females for #1 and males for #3. They seem to share some characteristics but I haven't examined the mouthparts yet.
All specimens have been collected from late April to mid July of this year. They seem to prefer relatively calm edges of fast glides. They prefer a clean substrate of small gravel. Measurements are given under each picture.
ADDED NOTE (October 8, 2014)
Spent a few hours over these with the dissecting needles in the last few days and all three appear to be Fallceon
species. Diagnostic features for Fallceon
nymphs are: no ventral femoral patch of setae, segment 2 of the labial palps poorly developed (minimal 'thumbs' or other projections) and a tuft of setae between the prostheca and molar region on at least the right mandible. References are: Lugo-Ortiz, McCafferty and Waltz "Contribution to the taxonomy of the Panamerican genus Fallceon
(Ephemeroptera: Baetidae), (1994). http://www.ephemeroptera-galactica.com/pubs/pub_l/publugoc1994p460.pdf
as well as Waltz and McCafferty "Waltz RD; McCafferty WP. 1987. New genera of Baetidae for some Nearctic species previously in Baetis
Leach (Ephemeroptera), (1987). http://www.ephemeroptera-galactica.com/pubs/pub_w/pubwaltzr1987p667.pdf
I don't have any idea what species #1 and #3 are. #2 may be Fallceon thermophilos
. The ID is tentative and the reasoning behind it is given below towards the bottom of this thread.
PHOTOS REMOVED AND PLACED IN NEW POST 11/11/14 http://www.troutnut.com/topic/8659/Fallceon-spp#42256