Last reply on May 19, 2007 by
GONZO
Jason,
When I first looked at this specimen, my first instinct was to guess that it was
biloba, especially coming from the upper Neversink. But, the more I compare it to the specimen I previously guessed as
biloba, the more I see subtle differences. The pronotum is a different shape and the knobs or spines extend further along the abdomen. Perhaps these are variable traits or gender differences, but I'm starting to wonder about both IDs.
Of the Eastern (or transcontinental) species, I'm pretty familiar with
dorsata and
biloba, and I've seen a few specimens that I'm pretty sure are
comstocki. These latter specimens had fearsome-looking long spines along the abdomen and I guessed at the
comstocki ID mostly because its nickname is the "spiny salmonfly."
I've seen cladistic diagrams that indicate that
scotti is considered to be the closest relative of
biloba, but it seems to have a more southerly distribution. (That diagram also seemed to explain why
Allonarcys is no longer favored as a separate genus for the
Pteronarcys species with spines or knobs.)
I'm not aware of the species descriptions of
proteus or
pictetii. Until I saw a survey of the Delaware River basin, I assumed that the large unknobbed
Pteronarcys that I had seen on the main branch were
dorsata (and that's what Ernie S. said they were), but the survey lists only
biloba,
comstocki, and
proteus.
Could someone provide some characters for these other species? It would help to resolve my current confusion and would be greatly appreciated.