Saturday, December 28, 2013
I have just made three changes to the Uenoid section of the EPT list I posted on 9/8/12. I have removed Neophylax atlanta and Neophylax concinnus, but I've added Neophylax fuscus. These changes were made for the following reasons.
1) I am now certain that the Uenoids I found yesterday at Buck Mt. Creek were Neophylax fuscus. I had one further thing that had to be checked: the spines on the anterior edge of the pronotum. Beaty's description of N. fuscus: "large blade-like spines on anterior pronotum" ("The Trichoptera of North Carolina," p. 87). Here is a photo that I just took this morning.
No question about it. That's a Neophylax fuscus Uenoid at the top of the page.
2) I have re-examined the larvae I found on 2/7/13 at the Doyles River that I thought were Neophylax concinnus. They weren't. They too were Neophylax fuscus; they look exactly like the larvae I found yesterday.
And 3) I am now quite sure that the Uenoids I found at the Rapidan River on 12/16 were Neophylax consimilis not Neophylax atlanta. Steven Beaty has told me that N. atlanta is extremely rare and only found in small headwater streams: he himself has never seen one. Of greater importance, you'll recall that I removed N. consimilis from consideration for the ID since the larvae I found did not have heads with a "stripe or pale area which is less than 1/2 head length" (Beaty, p. 86). I failed to note Beaty's full description: "head and legs dark brown or with stripe or pale area which is less than 1/2 head length." Vineyard, et.al. simply say this: "Head relatively uniform in colour, somewhat darker than nota or legs" (p. 45 or The Caddisfly Genus Neophylax), they make no mention at all of a pale stripe on the head. And the only Uenoid species I found last year at the Rapidan River was N. consimilis, so I'm now pretty sure that that's what I found on 12/16 as well.
That means that, to date, I have found five Uenoid species in local streams.
1. Neophylax aniqua
2. Neophylax mitchelli
3. Neophylax consimilis
4. Neophylax oligius
5. Neophylax fuscus
That sequence, as it turns out, corresponds to the Uenoid continuum that I've noted so far in our streams. That is to say -- as you move downstream from a headwater stream to a second or third order stream, you might find Uenoids all the way down, but you'll find different species. Thus, when I go to my favorite small mountain stream in Sugar Hollow -- a first-order, headwater stream -- and go to the highest part of that stream, I find N. aniqua and N. mitchelli. When I move down that stream to a site not far from the Moormans, I find N. mitchelli and N. consimilis. When I go to the South River up in Greene county, the Rapidan in Madison County, and the upper Doyles River, all second-order streams, but streams that are still in the mountains, I find only N. consimilis. And when I go to the lower Doyles River and Buck Mt. Creek, second order streams that have moved out of the mountains and into field country, I find N. oligius and N. fuscus.
That's the continuum that I'm currently seeing. If I need to revise this, I'll let you know.
Now if Beaty comes back and tells me the larvae I found at the Rapidan River really were N. atlanta I'll have some serious adjustments to make!
Friday, December 27, 2013
This should be the main story today -- I've finally found our third species of large winter stonefly, Strophopteryx fasciata. I was quite sure I'd find them in Buck Mt. Creek once the water subsided and cleared, and sure enough I picked up several today. This is late. I normally see them at the start of December. But everything seems to be late in starting this year. Still rather small...
but when they mature they look something like this: mottled head and nota; banded abdominal terga.
But for the main event -- we have another Uenoid (little northern case-maker) which requires identification.
I was expecting to see Neophylax oligius larvae in Buck Mt. Creek, the species I've found here before. But look at that face -- no pale frontoclypeal stripe whatsoever. Up close, it's dark brown to black with muscle scars at the rear.
There is also, from what I can see, no tubercle on top of that head, and it became clear with a microscope view that this is a species without clavate ventral gills. Note.
No gills that stick out like this.
So, what do we have? Looking at Beaty ("The Trichoptera of North Carolina," pp. 86-87) the possibilities would seem to be N. aniqua, N. concinnus, N. toshioi, and N. fuscus. N. aniqua and N. toshioi have tubercles that are easy to see, and a "short median tubercle" is often found on N. concinnus as well (Vineyard, et.al., p. 46). And there's another problem with N. concinnus for the ID: the ventral sa3 positions on segment 1 have 2 to 4 setae. Note the numerous setae at sa3 on the larvae I found.
So have we found N. fuscus? Beaty's description of this species is brief: "without clavate ventral gills on abdominal segment 2; large blade-like spines on anterior pronotum; head dark brown to black with light muscle scars. Occurs in northeastern Mountains and clean headwater streams to the Tar River.... Relatively rare." I'm not sure about the spines on the pronotum, but the rest seems to fit. And there are two other points made in Vineyard (p.24) that lead us in this direction. 1) "Abdominal segment I with ventral sa3 bearing 6 to 9 relatively long stout setae" and 2) Neophylax fuscus is the species in the genus best adapted to warm water conditions. In streams where it occurs with other Neophylax species, it always occupies the farthest downstream zone in the longitudinal gradient of species." The setae at sa3 on our larvae are long and stout -- I count about 10, and Buck Mt. Creek seems to be the kind of habitat herein described.
Neophylax fuscus is attested in the state of Virginia (Oliver S. Flint, Jr., Richard L. Hoffman, Charles R. Parker, "An Annotated List of the Caddisflies (Trichoptera) of Virginia: Part II. Families of Integripalpia, Banisteria, 31 (2008), pp. 3-23). These authors note: "The scattered records of this species show a distribution almost as large as that of N. concinnus: eastern North America from Minnesota to Nova Scotia, south to Missouri and northern Alabama. The Virginia records are from the Blue Ridge west through the Alleghanies. In contrast to most species of the genus, it prefers larger, warmer, lowland streams in these regions. Fairfax, Giles, Highland, Montgomery, Page, Pulaski, Rappahannock, Wythe cos."
Could be Neophylax fuscus. But I'll probably check in with Beaty to see if he has time to give these a look. More pictures -- dorsal views.
Other discoveries this morning.
1) Large winter stonefly, Taeniopteryx burksi/maura. Fairly large by now.
2) Small winter stonefly, Allocapnia pygmaea.
3) And our little pebble case-maker in the cornucopia, hooded case: Apatania incerta.
May the good weather continue!
Wednesday, December 18, 2013
My friend found this one last year in a small stream at high elevation (see the entry of 3/5/13) -- but for me, this was a first. This is the Nemourid stonefly, genus Soyedina. I found two of them today in one of my favorite streams for looking for insects. We have to leave this at the level of genus since only a few of these nymphs have been described to the level of species. I can tell you that only two species are attested for the state of Virginia (Stewart and Stark, Nymphs of North American Stonefly Genera, p. 217) -- S. carolinensis and S. vallicularia. Stewart and Stark provide illustrations of S. vallicularia (pp. 215-216), and I'd have to say I don't think that's the species we're finding.
Beaty says that Soyedina is "relatively rare," and describes it in the following way: "Nymphs 6.5-8.5 mm; pronotum with angular corners and a distinct posterolateral notch, with well developed lateral fringe; wing pads divergent; anterior thoracic gills absent." ("The Plecoptera of North Carolina," p. 5) Stewart and Stark note the key diagnostic characters in the following way: "The short legs and fringed, notched rectangular pronotum distinguish Soyedina nymphs from the nymphs of other non gilled genera.
The nymphs that I found were young and about 6 mm in length. It is the fore femora which are especially short, and we can see that in the photo above. For the other features -- pronotal notch with dense lateral fringe and divergent wing pads -- the photos my friend took last year show them better than anything I managed to get.
The divergent wing pads:
The pronotal notch and lateral fringe:
The nymphs she found -- like those that I found this morning -- were a little bit "muddy," but these are nymphs that are typically "found in leaf packs in seeps and small, cold streams." (Beaty, p. 5)
Love finding new things!
But I made lot of good findings this morning.
1. The first Taenionema atlanticum large winter stonefly of the season.
In another 1-2 months they'll be looking like this.
2. A Lepidostomatid (genus Lepidostoma) in a very nice case made of sand.
3. And three Uneoids that had also made very colorful cases.
Number one was Neophylax oligius: two and three will require more work. They appear to be the same species that I found at the Rapidan River, i.e. N. atlanta.
Nice day at a beautiful stream.
Monday, December 16, 2013
Now back to the species ID of the Uenoids I found yesterday. Everything points to Neophylax atlanta, a species that is "apparently rare" according to Beaty ("The Trichoptera of North Carolina, p. 86). This is confirmed by the source on all things Neophylax -- The Caddisfly Genus Neophylax (Trichoptera: Uenoidae), a book that was jointly authored by R.N. Vineyard, G.B. Wiggins, H.E. Frania, and P.W. Schefter (Royal Ontario Museum, 2005). "N. atlanta remains one of the rarest species of the genus in eastern North America." (Vineyard et.al., p. 45) For "Distribution" they note, "Neophylax adults have been collected near small streams in the foothills of the Appalachian Mountains in the southeastern United States from Virginia to Alabama."
I'll approach this ID first in a negative then in a positive way. First, have a look at this microscope shot of one of the larvae, noting the clavate ventral gills and the dark head and legs.
1. Process of Elimination. Of the 9 species of Neophylax described by Steven Beaty (pp. 86-87), only 5 -- N. atlanta, N. oligius, N. consimilis, N. mitchelli, and N. ornatus -- have clavate ventral gills, so we know where to begin. We can eliminate oligius and consimilis since our larva has no markings at all on its head/face. N. oligius, you'll recall, has a well defined yellow-orange stripe...
and N. consimilis has one or two pale spots which sometimes merge to form a short stripe.
The head/face of our larva is uniformly dark brown/black. We can also rule out mitchelli. Mitchelli has a very distinct tubercle on top of its head --
nothing like that on our larva. There may be a low rounded frontoclypeal tubercle on our larva, but Beaty assures me that such a "bump" is common on Neophylax.
2. Larval Description. But what is the larval description of N. atlanta? Can we see the anatomical features we need to see for that ID? Two of those features are easy to see: our larva has ventral gills and it does not have a "frontoclypeal tubercle" (Vineyard et.al., p. 45). But there are five other features that require some microscope work. (For the detailed larval description, see Vineyard, et.al., p. 45).
1. There is "a relatively large number of long pronotal setae." Yes.
2. There are "relatively short spines along the anterior margin of the pronotum." Yes.
3. We should see "about 4 setae" at the sa3 position of abdominal segment 1. I think I can see 5 on this larva -- probably close enough.
4. There are "lateral gills" at 2p and 3a -- i.e. on the posterior (p) edge of abdominal segment 2 and the anterior (a) edge of segment 3. They're difficult to see...but they're there. Look closely; the tips overlap.
5. And now for the toughy, which apparently is a critical feature. Ugh! There is a "spiculate microsculpture on the pronotum," (p. 45), i.e. it looks "grainy" or "cobbled." I can see it with my microscope. This is the best I could do with my photos. A really good look would probably require an electron microscope.
When all of this evidence is taken together, I think Neophylax atlanta is a pretty safe bet for our ID. I've added this taxon to our EPT list.