Troutnut Forum

>

Specimen Discussion

> proteus, biloba, and comstocki

The Specimen

The Discussion

Beardius	August 1st, 2008, 12:53 pm
Posts: 19	Pteronarcys proteus has abdominal knobs but has a squared off pronotum (no projection of knob). It differs from dorsata in having knobs on the abdominal segments. There is a picture of a young Pteronarcys proteus nymph here: http://www.discoverlife.org/mp/20q?search=Pteronarcys+proteus Pteronarcys comstocki has pronotal projections and a spine-like projection on the anterior mesonotal wingpad. I only found them in one stream (trib of Kettle Creek in central PA) of the dozens I've collected. I have not collected them in MD, but they are reported from WV and PA. There is a photo of an immature nymph here: http://www.discoverlife.org/mp/20o?search=Pteronarcys+comstocki Pteronarcys biloba has pronotal projections but no spines on the wingpads. P. biloba is common up north (NY, VT, NH, ME, etc.). The photo above is of P. biloba. Nice photo here: http://www.discoverlife.org/mp/20q?search=Pteronarcys+biloba P. scotti is found in the south (SC,GA, etc.) I never collected P. dorsata, so I figure it must be in larger or warmer rivers.
GONZO	October 28th, 2008, 11:51 am
Site Editor "Bear Swamp," PA Posts: 1681	I just noticed that this thread was an answer to questions that I raised some time ago in the related thread. Beardius' comments and the links to photos and identifications done by Donald Chandler (Dsc1) are very helpful. It is now easier to see that this is biloba and that the other specimen (#490) is probably proteus. In addition to the traits that Beardius mentions, the abdominal knob seems to dramatically diminish or disappear after the 7th segment in proteus, but biloba usually has a prominent knob on segment 8. I really don't know how reliable this is, but it seems to be consistent in all of the specimens I have seen.

Quick Reply

Related Discussions

Title	Replies	Last Reply
Help with Pteronarcys species characters? In Pteronarcys biloba Stonefly Nymph by GONZO	0
Re: Pteronarcys californica nymph In the Photography Board by Millcreek	2	Jun 14, 2016 by Millcreek
Re: Some pics from a NC stream In the Identify This! Board by RyanBednar	3	Apr 26, 2010 by RyanBednar
Re: This is not Ephemera simulans In Hexagenia limbata Mayfly Nymph by Beardius	1	Aug 2, 2008 by Troutnut
Re: Northern Ontario Canada, Stonefly question. In General Discussion by Snowsquatch	4	Sep 4, 2012 by Entoman
Re: Latin Redux In General Discussion by Martinlf	10	Feb 12, 2007 by CaseyP
Re: little black stoneflies In the Stonefly Family Capniidae by CaseyP	5	Nov 29, 2012 by Entoman
Re: identification needed In Rhithrogena impersonata Mayfly Nymph by Kinza	2	Feb 6, 2017 by Crepuscular
Re: Lepidostoma? In Lepidostoma Little Brown Sedge Larva by PaulRoberts	2	Aug 16, 2012 by PaulRoberts
Re: parasites? In Isoperla Stonefly Adult by Litobrancha	9	Oct 22, 2006 by GONZO

Troutnut.com is copyright © 2004-2020 Jason Neuswanger (email Jason). See my FAQ for information about use of my images. privacy policy