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.
Luke, you mentioned there's so much we don't know in the fractercula thread. From an angling importance standpoint, which genus/species groups seem to have the most work needed? Which ones have issues that interest you the most? Entoman
There are plenty of folks who spend more time on the water than me these days, and that experience and observation is valuable.
What part of the world are you asking about? Konchu
...and new discoveries in "well-studied" groups are all things that no longer surprise me. That big barcoding paper we put out awhile back lays out a bunch of the areas of needed inquiry. I think many genera need a good look, including the common genera ..., Ephemerella...
It seems people are often coming across specimens that don't fit well with published descriptions.