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Topic: Mayfly - Paraleptophlebia bicornuta - nymph
TaxonJan 30, 2011 09:52 0009-0001

WA, USA

Topics started: 127
Replies made:  623

What is the genus of this tusked mayfly nymph, which was collected in a kick-net sample from the S. Fork Snoqualmie River in W. WA on August 16, 2007?

Hints:

1) This is not a genus normally associated with having tusked nymphs.

2) The abdomen is not shown, as that might make the challenge a bit too easy.


Roger Rohrbeck
EntomanJan 30, 2011 20:24 0009-0002

Northern California

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Paraleptophlebia packi? (Mahogany Dun) Seems like this pic is of a fairly immature niad, which makes sense because this is a hatch of mid to late Fall. The tip off is the lack of wingcase development. Antennae length, head proportions and tusk development seem a off from fully developed.

Kurt
Entoman
TaxonJan 30, 2011 21:51 0009-0003

WA, USA

Topics started: 127
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Kurt-

You are good! You nailed the genus. As to species, Paraleptophlebia packii (original spelling was incorrect, and has been fairly recently revised) is limited to the Rocky Mountain states, whereas the distribution of P. bicornuta (another tusked species) extends west to the Pacific-Coast-bordering province and states of BC, WA, and OR.


Roger Rohrbeck
EntomanJan 31, 2011 02:42 0009-0004

Northern California

Topics started: 55
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Roger -

Thanks for the compliment, and the correction on the spelling. Those pesky revisions again! P. bicornuta... Agh!! It was a coin flip for me without seeing the gill structure. Since the tusks are more pronounced in the bicornuta specimens in my home river, I went with packii. We have excellent populations of bicornuta down here. I know about the reported distribution of the Leptophlibiidae, but I think there's a lot left to learn in that regard so I didn't let that sway me to much.

The lack of substantial indentation between head and pronotum makes the whole forestructure look a little too conical for a Leptophlebiid. For a few seconds I thought I might have been looking at a heretofore undiscovered West Coast species of Anthpotamus! But the forelegs are all wrong (I know, but it was only a few seconds). I was really scratching my head until I luckily noticed the lack of development in the wing pads.

Had I seen the full picture, I have to admit I probably would have been even more confirmed in my choice, because the ''palm to filament ratio'' of the gills is much more inline with packii and not even close to bicornuta. It's a little hard to make out, but i don't think I see tracheal branching in the gills signifying bicornuta either. Heck, I think you may have a packii where it isn't supposed to be! Wouldn't that be fun.

Before we get our hopes up, the following caveat needs to be mentioned... The full picture confirms my suspicion that this naiad may have had a few instars to go? It's risky business trying to judge size by the surrounding particulate matter, but I'd guess less than half grown (5 to 7 mm)? This might have an impact on determining the differences between the two. I haven't read anything about the stage in development where they begin to assume their ''keyable'' gill structures, so the lack of conformity in this specimen to bicornuta may not be reliable. It can be tricky working with immature nymphs. I remember years back when a particular 7mm or so Heptagenid kept showing up in my samples with hair like gills on a few body segments. Gave me fits until a kind hearted Entomologist pointed out I was capturing only half developed specimens. Using keys on immature naiads can be very problematic.

Thanks,

Kurt
Entoman
TaxonJan 31, 2011 06:43 0009-0005

WA, USA

Topics started: 127
Replies made:  623

Kurt-

Okay, here is a photo of a mature Paraleptophlebia packii (or P. bicornuta) nymph, which I collected (5) weeks later, on September 20, 2007, at the same location. The gill filament branching looks to be identical to the immature? So, I presume both are P. packii, right?


Roger Rohrbeck
EntomanJan 31, 2011 13:26 0009-0006

Northern California

Topics started: 55
Replies made:  783
Yes, unless I'm interpreting the keys wrong (which is always a possibility). Ah.. A ''ripe'' nymph... Much easier to work with. Notice the difference in head conformation, tusk size, and antenna length from the other sample? That's why I was scratching my head a little. Did the mature nymph run about 12 mm? Still not close up enough to determine conclusively a lack of tracheal branching, but it doesn't matter since it's pretty easy to see that this specimen has nowhere near the 1 to 1 palm/filament ratio of bicornuta. I think we have a match? Perhaps in the future, scientists will revise the distribution charts. Maybe I'm getting ahead of myself since I don't know if the evidence would be considered too isolated and/or anecdotal (or just plain wrong)... Maybe you know a practicing entomologist with expertise in mayflies that would be willing to officially ID and document your sample? Roger, I think it's worth checking out...

On a side note (fishing): This family has so many shared traits with the other groups (except clingers) both in terms of morphology and behavior, that I've always had a problem with arbitrarily putting them in with the crawlers. They clearly deserve their own grouping among us fisherfolk. How about schoolers? They are the only ones I know that exhibit the behavior of migrating up the stream margins to emergence sights like a school of minnows. Fish go nuts for 'em! Contrary to most published reports, they swim really well, and for much longer distances than the faster Baetidae. Not sprinters maybe, but they are definitely the ''long distance specialists'' of the Order. When they're on the move, swinging a nymph on a slow sinking line in close to shore and fished back with a hand twist or short strip retrieve can be deadly. A fun way to fish! I wish I was camera'd up so I could send you photos of the flies I use. Oh well... Soon maybe...

Thanks,

Kurt
Entoman
TaxonFeb 04, 2011 00:04 0009-0007

WA, USA

Topics started: 127
Replies made:  623
Kurt-
Did the mature nymph run about 12 mm?
Regrettably, I don't know for sure. I suspect it may have been somewhat shorter than that, but I didn't record the length, and as I recall, I was collecting in support of a former Mayfly Central entomologist's participation in a DNA study at the time, so I shipped the specimen off to him, and no longer have it.
Maybe you know a practicing entomologist with expertise in mayflies that would be willing to officially ID and document your sample?
Yeah, I sure do. I sent off an email inviting him to join the forum earlier today, but haven't yet heard back from him.
How about schoolers?
Hmm. Perhaps, but I don't really have an opinion on this.


Roger Rohrbeck
EntomanFeb 04, 2011 03:10 0009-0008

Northern California

Topics started: 55
Replies made:  783
Hi Roger - Thanks for the reply. I was curious about the size to see if it corresponded with the specimens I've taken down here. The duns run a full sized 14 or small 12 and are uniformly (body, legs, tails) a rich chocolate brown with a slight mahogany cast. There is little discernible contrast between dorsal and ventral surfaces. They have dark dun wings. I had excellent fishing during this hatch just this past October.

What I find fascinating is that you collected it out of a coastal drainage (I'm assuming?). A lot of the specimens I've collected over the years came from Fall River which while technically draining into the Pit R. and from there the Sacramento, it's character seems to have much more in common with Rocky Mountain watersheds (as in south east Idaho).

That's good to hear about the entomologist. It would be really great if he can find the time.

Calling them ''schoolers'' is just a musing of mine. They are built more like a swimmer; kind of a long tailed Baetid with heavy gilling. They look nothing like the other crawlers. The tusked ones look more like burrowers. Since these categories are based on the unique behaviors of the member families anyway, why not give them their own category? Their habits are different and their morphology is definitely different. It's as if nature took bits and pieces of the other families morphology and combined them into this one.

Kurt


Entoman
TaxonFeb 04, 2011 04:29 0009-0009

WA, USA

Topics started: 127
Replies made:  623
Kurt-
What I find fascinating is that you collected it out of a coastal drainage (I'm assuming?).
Well, technically speaking, the term ''coastal drainage'' refers to a river that drains into the ocean. The rivers in my immediate area all drain into Puget Sound, which might be analogous to rivers which drain into Hudson's Bay, but of course, on a much less grand scale. So, is there some ramification of drawing this this distinction? Geez, I have no idea.
Since these categories are based on the unique behaviors of the member Families anyway, why not give them their own category?
Guess I don't really have an opinion on that one.


Roger Rohrbeck
EntomanFeb 04, 2011 17:08 0009-0010

Northern California

Topics started: 55
Replies made:  783
Hi Roger,

Yeah, the point I was trying to make was the distinction between your specimens and interior specimens respective homes. Because of the unique area that is the great basin (of which some of eastern WA is a part, I think), finding packii would be more plausible. Even overlapping with bicornuta is not earth shattering because I think such overlapping is possible at the fringes of their adjacent distribution (both possibly competing for the same niche?). Anyway, nothing fringe about your collection location if it's coastal (west of the Cascades), which is why I think your find is so fascinating. The reason for the question mark was because I didn't want to make an assumption about your river's location. It could have been in Eastern WA for all I knew. Thanks for the more refined definition of ''coastal drainage'' anyway.

Regards,

Kurt
Entoman
TaxonFeb 04, 2011 19:41 0009-0011

WA, USA

Topics started: 127
Replies made:  623
Kurt-

Well, I see konchu has registered on the forum in the interim. So, perhaps he will know for certain whether this is Paraleptophlebia packii as you suspect, or P. bicornuta as I had previously believed. He is also the one to whom I sent the specimens in question, so perhaps he will even have gotten some DNA evidence. I'm not going to bug him about this right now, but rather, am hoping he will eventually stumble upon this topic and respond in some way.


Roger Rohrbeck
EntomanFeb 04, 2011 22:47 0009-0012

Northern California

Topics started: 55
Replies made:  783
That's great news!
Entoman
EntomanFeb 16, 2011 20:48 0009-0013

Northern California

Topics started: 55
Replies made:  783
Hi Roger,

Finally found some time to look for documentation of my opinion on P. packii. I found confirming descriptions in Caucci/Nastasi, but even clearer is Knopp & Cormier, pgs 268 and 269. The chart on 269 incorporates the diagrams on 268 under ''Gill Ratio'' and ''Trachael Branching''. Another interesting thing I noticed (though not mentioned in the text that I can find) is the differences between the anterior margins of their heads; bicornuta's is noticeably more convex with a medial projection on the anterior edge of either the frons or labrum (can't tell from the diagram) lacking in the diagram of packii.

Regards,

Kurt
Entoman
TaxonFeb 16, 2011 22:22 0009-0014

WA, USA

Topics started: 127
Replies made:  623

Kurt-

That is what Knopp and Cormier say. However, in the spirit of good-natured rebuttal, I offer this photo of P. bicornuta from PNW entomologist, Jeff Adams.


Roger Rohrbeck
EntomanFeb 18, 2011 11:36 0009-0015

Northern California

Topics started: 55
Replies made:  783
Roger-

Ah! Very interesting... The same information in K & C is also provided in C & N's ''Guide to Instant Mayfly Identification'' (which I might add is a very handy little field guide with excellent simplified keys). Even though both were written by laymen, my understanding is they have been extensively reviewed. Until this confusion, I have always considered them reliable. Somebody's wrong. Luckily, if it's me I can blame those other guys.

I believe it's almost axiomatic that gill conformation is determinative with mayflies. It will be interesting to find out, but maybe the example from Adams is possibly a proofing error in picture selection? Maybe it slipped through the cracks (lack of proper ''proofing'' is a big problem with web info). My reasoning? The others actually documented the difference in their keys or discussions which can't be accidental. If they're wrong it's a much bigger boo boo.

BTW, I always consider any argument, rebuttal, correction, or admonition from you as ''good-natured'' (unless you tell me you're pissed).

Regards,

Kurt
Entoman
toolmanFeb 24, 2011 21:04 0009-0016

Alberta, Canada

Topics started: 1
Replies made:  21

Hi Roger, great to see the new forum.
Collected from the Bow river, Alberta, Aug/2008.
Cheers,
Greg
TaxonFeb 24, 2011 22:43 0009-0017

WA, USA

Topics started: 127
Replies made:  623
Hi Greg,

Great to have you aboard. Hey, that's a really cool photo of a mature Paraleptophlebia bicornuta nymph.


Roger Rohrbeck
toolmanFeb 25, 2011 00:04 0009-0018

Alberta, Canada

Topics started: 1
Replies made:  21

Roger, I thought you might recognize that photo. Here's another that may fit in the discussion, taken at the same time and from the same location as the nymph.
EntomanFeb 25, 2011 00:48 0009-0019

Northern California

Topics started: 55
Replies made:  783
OK guys, rub it in! I'm waiting to hear from Konchu...

Nice to meet you Greg. BTW, nice photo of the female P. packii dun...

Regards,

Kurt
Entoman
EntomanFeb 26, 2011 21:44 0009-0020

Northern California

Topics started: 55
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BTW, how about muddying the water a little more? There are two other Paraleptophlebia species in the Northwest with tusks: P. helena and P. zayante. Wonder how they fit in to our deliberations? The description of P. helena in ''Aquatic Insects of California'' (Usinger) is very interesting. It is the only species listed as having a black ''V'' on the vertex of its head (P. zayante is described as having its vertex completely washed in black). Also, while I know of no documentation, other than a brief mention by Schwiebert in his revised ''Nymphs'', that specifies a difference in tusks as being determinative. The diagram on pg. 94 (Usinger) clearly shows a more circular shape than either P. bicornuta or P. packii. It's interesting that the left tusk tip finishes inside the right one. Considering these three characterisics are present in your immature specimen and especially Greg's, a case could be made for P. helena? Interesting...

Kurt
Entoman
EntomanMar 06, 2011 02:12 0009-0021

Northern California

Topics started: 55
Replies made:  783
Roger,

Trying to dig deeper into the possibility of P. helena (see post above), I came across an interesting link regarding invertebrates of the Lake Tahoe Basin you may want to keep for future reference. #
www.fs.fed.us/psw/publications/documents/gtr.../gtr-175-appendixH.pdf
#
FYI, it lists the presence of ALL four tusked species of Leptophlebids within the basin and gives their reporting the highest reliability rating, for what that's worth. Whether all four are actually present or the listing of all four is simply because species identification hadn't been determined beyond the specimens having tusks is a possibility I guess.

Regards,

Kurt
Entoman
TaxonMar 06, 2011 14:06 0009-0022

WA, USA

Topics started: 127
Replies made:  623
Kurt-

Okay, the link is actually:
http://www.fs.fed.us/psw/publications/documents/gtr-175/gtr-175-appendixH.pdf

This led to my discovering the following paper by W. C. Day, which provides descriptions and illustrations of Paraleptophlebia helena and P. zayante:
http://www.famu.org/mayfly/pubs/pub_d/pubdayw1952p17.pdf


Roger Rohrbeck
EntomanMar 06, 2011 17:51 0009-0023

Northern California

Topics started: 55
Replies made:  783
Hi Roger,

Excellent detective work! Well, another piece to the puzzle is added. Day is certainly describing the pale quadrangle we see on the specimens in this thread. The black ''V'' also. The fact that he describes the quadrangle as white is probably due to preservative bleaching. Though he mentions these characteristics as a way to differentiate helena from the other species he refers to, P. bicornuta and P. packii are NOT mentioned. Too bad we can't seem to find a description of bicornuta or packii heads for comparison. While it's compelling that every diagram I've seen of these two (which is damn few) don't show these peculiar markings or tusk shape, that's hardly conclusive. Unfortunately, my notes from past collection activities don't make any mention of these traits either. Based on all this (not to mention confusion over gill structure), I'm rethinking my understanding of the whole ''P. tusker group''. Very perplexing... and fascinating!

Regards,

Kurt
Entoman
EntomanMar 27, 2011 00:20 0009-0024

Northern California

Topics started: 55
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Hi Roger,

Going through my copy of ''Aquatic Insects of California'' looking into something else, my eyes were drawn to the table of Paraleptophlebia nymphs on Pg. 94 again. For some reason, I failed to previously mention three other characteristics that match up P. helena with the pictures on this thread pretty well.

1. No tracheal branching in the gills
2. Strongly marked abdominal tergites
3. Fore tibia marked with a pale brown spot

Coupled with Day's description of a black V mark and pale quadrangle on the head, is the case building for P. helena further?

Anyway, revisiting this has inspired me to post a synopsis of what has become a pretty long thread.

Distribution:
Though not without some controversy, the general consensus (if one can be said to exist) is that helena is primarily a coastal California species, packii is primarily limited to the Rockies, and bicornuta is more widespread throughout the North West. This is the most convincing evidence for bicornuta, though one of the photos submitted originated from the northern Rockies. As a caveat, my comments regarding the distribution of Attenella soquele in the A. delantala thread may have some bearing on this issue as well.

Taxonomy:
Reliable information helpful in determining species for these tusked Paraleptophlebia is hard to find. Other than Day's description of helena, the only other non-angler source on this thread was Jeff Adams (Xerces Society) ventral photo labeled as bicornuta, where deep clefted non-tracheal gills were clearly in evidence.

Information provided in angling-entomology literature is scant and contradictory to a substantial degree. Schwiebert briefly discusses differences in tusks as a way to tell them apart. But, other than to describe packii's as more ''tong'' than ''sickle'' shaped, no other information is provided. This is in direct contradiction to diagrams in Knopp which show the opposite. As to head and pronotal markings on bicornuta, both Knopp and Arbona diagrams show a large dark ''U'' shape with its base at the anterior of the pronotum and no distinct markings on the head. Neither diagram packii. The only information provided by all four sources involves descriptions of differences in gill structure involving the depth of the clefts between the prongs and the existence of tracheal branching or lack thereof.

Here's the score regarding gill structure among the four angler/entomological authors:

P. helena: Not addressed

P. bicornuta:
shallow cleft - Schwiebert, Knopp & Cormier, Caucci & Nastasi
deep cleft - None
tracheal - Schwiebert, Knopp & Cormier, Caucci & Nastasi
non-tracheal - Arbona

P. packii:
shallow cleft - Schwiebert
deep cleft - Knopp & Cormier, Caucci & Nastasi
tracheal - Schwiebert, Arbona
non-tracheal - Knopp & Cormier, Caucci & Nastasi

Note: Out of a possible 6 points (Arbona doesn't mention depth of cleft), Here's how they score in relation to this threads photos:

P. bicornuta - 1
P. packii - 4

What to conclude from this?

1. If the photos on this thread are of helena, the issue is dodged.

2. If the photos are of bicornuta, Arbona is at least half right, and the rest are wrong across the board.

2. If the photos are of packii Arbona is at least half wrong, Schwiebert is wrong across the board, and all the others are vindicated.

4. Though it may be interesting, none of this gets us any closer to a resolution.

Regards,

Kurt
Entoman
EntomanMar 27, 2011 23:02 0009-0025

Northern California

Topics started: 55
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When they're on the move, swinging a nymph on a slow sinking line in close to shore and fished back with a hand twist or short strip retrieve can be deadly. A fun way to fish! I wish I was camera'd up so I could send you photos of the flies I use. Oh well... Soon maybe...

Here they are. My favorites for this critters when they are schooling and hatching.

Regards,

Kurt
Entoman
TaxonMar 28, 2011 02:49 0009-0026

WA, USA

Topics started: 127
Replies made:  623
Kurt-
I'm rethinking my understanding of the whole ''P. tusker group''. Very perplexing... and fascinating!
Yep, it sure is.


Roger Rohrbeck
GONZOMar 28, 2011 18:45 0009-0027

"Bear Swamp," PA

Topics started: 4
Replies made:  163
In support of Roger's case for bicornuta, here's another nymph photo from the IWS Image Library:
bicornuta
I vote for option #2 (the first #2) in Kurt's previous post.
BTW, very nice flies, Kurt. Those will work, with or without tusks.

TaxonMar 28, 2011 19:14 0009-0028

WA, USA

Topics started: 127
Replies made:  623
Oh man, am I ever enjoying all this bug talk. It just don't get no better than this.


Roger Rohrbeck
EntomanMar 28, 2011 23:52 0009-0029

Northern California

Topics started: 55
Replies made:  783
Hi Guys,

Lloyd - Thank you. Coming from you, I take the compliment as high praise. I enjoy all your posts, and found your book well done and right on the mark. Very insightful! BTW, I do tie tusks on my hinged Hexigenia nymphs. You'll know I've gone off the deep end when I do it for these guys!

Roger - Very glad you're enjoying yourself. You sound like a kid on Christmas morning! (I feel the same way about it)

About this critter... Sorry... I guess I'm that twelfth ''pain in the ass'' juror holdout. For me, there's just way too much ''expert'' opinion all over the map on this one to accept another non-authoritative photo and close the book. What really opened the can of worms was the only authoritative source so far (Day) described this guy as helena. The only reason that didn't seal the deal is because he doesn't include either packii or bicornuta in his review. Doesn't mean I think bicornuta is wrong, I'm just in the middle and can't put my imprimatur on something I'm not pretty sure of (not that that matters a hoot to anybody but me). What we really need is something authoritative - a nymph key, a paper discussing the differences between these species, anything that's largely recognized as authoritative in entomological circles.

I'm tapped out for now... Do you guys have anything else in your haversacks? I'd love to know who's books I need to mail back.

Regards,

Kurt

P.S. BTW, as mentioned in the thread earlier, my samples have always looked more subdued brown, not unlike Greg's packii posting. If I lived near you Roger, I'd tie up some helena patterns that simulate the ''diamondback'' look. Maybe experiment with weaving?
Entoman
GONZOApr 01, 2011 09:50 0009-0030

"Bear Swamp," PA

Topics started: 4
Replies made:  163
The same information in K & C is also provided in C & N's ''Guide to Instant Mayfly Identification'' (which I might add is a very handy little field guide with excellent simplified keys). Even though both were written by laymen, my understanding is they have been extensively reviewed. Until this confusion, I have always considered them reliable.

If by ''extensively reviewed'' you mean that the content was verified by entomologists, that does not appear to be the case. K & C’s book was “reviewed” by Stephen L. Jensen, but this obviously fell short of verification of all information based on existing scientific literature (which would have been a prodigious task). The species under discussion provide good examples of that:

The identification table in Knopp and Cormier (pg. 269) indicates that packii has a 1:3 gill ratio, that tracheal branching is absent, and it lacks posterolateral projections or spines. In contrast, Needham's original description says that ''Each gill is divided almost to the base in two long, lanceolate, accuminate lobes, in each of which there is a coarse central trachea which bears short pinnately arranged branchlets. There are short, sharp lateral spines on abdominal segments 8 and 9....'' Needham’s diagram of the P. packii gill shows at least a 5:1 ratio (corresponding to the K & C “c” diagram, not the “b” diagram indicated) with prominent tracheal branching.

K & C’s book also says that ''P. helena, a species indigenous to California, is also an early spring emerger.'' Day's original specimens (including adults) were collected in October, 1949.

Based on the accounts of the original nominating authors, the info in K & C appears to be wrong on all four counts.

If the C & N “Guide” describes packii as lacking tracheal branching, that information would contradict Needham's original description as well as the table on pg. 113 of C & N's Hatches, which indicates that it has tracheal branching and spines on AB 8 and 9 (which is consistent with the original description).

...the only other non-angler source on this thread was Jeff Adams (Xerces Society) ventral photo labeled as bicornuta....

I believe Jeff's photo is a dorsal shot of an immature, as evidenced by the antennae originating above the tusks and the underdeveloped wing pads.

What really opened the can of worms was the only authoritative source so far (Day) described this guy as helena. The only reason that didn't seal the deal is because he doesn't include either packii or bicornuta in his review.

To be fair to Day, he never saw ''this guy.'' In Day's 1952 paper describing helena and zayante, he does include mention of packii and bicornuta, but distinguishes them from helena based on characters of the male imago (diagrams of the terminalia) and with the comment that ''The male adult of P. helena is distinguished from other Paraleptophlebia spp. having nymphs with tusked mandibles, by the deep brown wings.'' It's speculation, but perhaps one reason for this is that the nymphs may not be readily distinguishable in some cases. If so, it would not be surprising that Day's description of the helena nymph might match bicornuta in many ways. He does not indicate anything that would be determinative in distinguishing the nymph of helena from other tusked Paraleptophlebia nymphs, except with regard to zayante (the tusks of zayante ''are one-third shorter, and are heavier and more curved'').

All of this is a very roundabout way of explaining why I believe that all of the photos in this section are likely to be bicornuta and that, of the angler/ento/book info provided, only Arbona's information seems on target. Although distribution reports are never conclusive in ruling out an identification, bicornuta is reported in all of the areas corresponding to these photos, and neither helena nor packii is reported from any of them. If helena were as widespread as indicated by this small sampling of photos, I would find it surprising that adults with deep brown wings would have been missed in all previous reports.

But that's just my assessment of this rather convoluted thread, FWIW.

TaxonApr 01, 2011 10:42 0009-0031

WA, USA

Topics started: 127
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Lloyd,

Thanks for your insights. It has been a long winter, and Kurt and I have been patiently (well, at least most of the time) awaiting your weighing in on numerous photos, not the least of which being these.


Roger Rohrbeck
EntomanApr 01, 2011 15:05 0009-0032

Northern California

Topics started: 55
Replies made:  783
Hi Lloyd,

Thanks very much for the detailed analysis of the science. It's what we've been hoping for. Your case is so strong that I would be very surprised if these critters weren't bicornuta. Thanks for confirming my suspicions about the angling texts, though I would qualify a little in that Arbona is at least not wrong in the info provided. His material is just too scanty to say he's ''right'' in an overall way.
''The male adult of P. helena is distinguished from other Paraleptophlebia spp. having nymphs with tusked mandibles, by the deep brown wings.'' It's speculation, but perhaps one reason for this is that the nymphs may not be readily distinguishable in some cases. If so, it would not be surprising that Day's description of the helena nymph might match bicornuta in many ways. He does not indicate anything that would be determinative in distinguishing the nymph of helena from other tusked Paraleptophlebia nymphs............ If helena were as widespread as indicated by this small sampling of photos, I would find it surprising that adults with deep brown wings would have been missed in all previous reports.
On the nymph - I believe you are right. I made the same point earlier in this thread in several locations, which is why we all agree that Day's descriptions of helena though matching well, aren't conclusive enough. In fact, I'm beginning to suspect that helena and bicornuta are so close in appearance that the only way to know for sure might be through rearing. On the adult - Good stuff! Didn't know about the brown wings... I'm assuming by ''adult'' Day meant imago? Anecdotally speaking, I cannot remember ever seeing a brown winged Mahogany Dun Spinner or ever even hearing of one. Reporting on these species is so scant though, who knows?
I believe Jeff's photo is a dorsal shot of an immature, as evidenced by the antennae originating above the tusks and the underdeveloped wing pads.
The fully visible coxi say ventral. The ''undeveloped wingpads'' look like sternal plates to me. Because of this I thought the antennae were showing through the clear tusks. After a closer look, more significant than the antennae are the abdominal markings which are more consistent with a ventral view. If I'm wrong and it is a dorsal view, what about the head markings? Too beat up maybe.
To be fair to Day, he never saw ''this guy.''
You're absolutely right. Another example of my writing poorly expressing the thought. What I meant was Day's description of helena matched the photos in question.

A new tidbit - Dr. William Shepard has a revised list of California Aquatic Insect Species (post Usinger) published on UC Berkley's ESSIG museum site (there's also a link to an interesting paper you guys might find valuable). Curiously, the only species of the group he has listed is bicornuta! Though still listed by Purdue, perhaps a brand new phylogenetic test has rendered helena and zayante synonyms of bicornuta? Perhaps a clerical error? Oh well... If even the scientists can't agree...

Regards,

Kurt


Entoman


Created: 01/12/2010   Last modified: 12/26/2014    www.FlyfishingEntomology.com