Saturday, January 19, 2013

Neophylax ornatus: a high elevation Uenoid caddisfly larva

With our valley streams high from four days of rain, I decided to look at a small stream in Sugar Hollow today, one that's higher up than those to which I normally go.  I can drive most of the way -- but there's still a bit of a hike at the end.   It was worth it.  I found two new -- for me -- Uenoid caddisfly species: the one in the photo above is Neophylax ornatus, the second I found is either N. aniqua or N. mitchelli (more on that later).

Here are a few more photos of Neophylax ornatus before we read Steven Beaty's description.


ventral (eye to eye!):

Steven Beaty describes N. ornatus in the following way ("The Trichoptera of North Carolina," p. 87):

N. ornatus -- well developed clavate ventral gill on abdominal segment 1; head yellow to lighter brown sometimes with lighter muscle scars.  Occurs in 1st order Mountain and Piedmont streams.  Uncommon. 

1) The stream that I went to today was a 1st order stream.  2) The yellow/light brown head is clear in the photo at the top of the page: all other Uenoids that I've seen so far have heads that are primarily dark brown to black.  3) For the muscle scars and the clavate gills, we need a microscope view.

For a more complete N. ornatus description, see pp. 61-63 in R.N. Vineyard,,  The Caddisfly Genus Neophylax (Trichoptera: Uenoidae).   They add that "lateral gills are rarely present," (p. 62), and I saw none on this larva.  On distribution, Vineyard notes that "This species is widely distributed in eastern North America, ranging from Newfoundland to southern Ontario, and south along the Appalachian Mountains into northern Alabama, Georgia, and South Carolina."  It has been attested for the state of Virginia, by the way, in the Shenandoah National Park -- to which I was real close today.

Also of interest in Vineyard -- his comments on the "Biology" (p. 63): "Neophylax ornatus is restricted to springs and small first-order streams.  It is often found in the same habitats as N. aniqua and N. mitchelli."

Which brings us to larva number two.  This Uenoid was extremely small with a case of 3 mm.

This is the first Uenoid I've found that has a "tubercle" (pointed bump) on its head.  Let me point it out in a series of photos.

and a close-up:

The tubercle  -- and lack of a "pale eye stripe laterally" (Beaty, p. 87, on N. toshioi), leads us to two possibilities for the ID: N. aniqua or N. mitchelli.  Neither species has "lateral abdominal gills," but N. mitchelli has clavate gills on abdominal segment 1; N. aniqua does not.

I cannot see clavate gills on this larva, which would lead us to N. aniqua.  However, given the size of the larva, it could be that the gills are too small to see.  Moreover, the case was not only small, it easily fell apart.  Those features point to N. mitchelli: "Case often smaller and more fragile than other Neophylax species." (Beaty, p. 87, on N. mitchelli)  But there is one more thing that points to N. aniqua: the median tubercle on N. aniqua is "stout [and the] distance across [the] base [is] more than [the] distance from [the] base to [the] tip" (Vineyard, p. 42);  that of N. mitchelli is "slender and curved" (Vineyard, p. 56).  At the moment, I'd go with N. aniqua.  Stay tuned.

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