Sunday, December 9, 2012

Almost had it: the Doyles River caddis was Apatania incerta -- family, Apataniidae

On that cased caddis I found yesterday -- Dave Ruiter pointed out that the case just didn't seem right for Limnephilid.  I had to agree.  So, I've continued to work on this one, and I finally figured it out.
This is a new species of caddis for me: family, Apataniidae; genus, Apatania; species, incerta.  In Wiggins' first edition of Larvae of the North American Caddisfly Genera (Trichoptera), (Toronto: University of Toronto Press), published in 1977, Apatania was considered a Limnephilid genus: it was changed to a family (Apataniidae) in his 2nd edition, published in 1996 (see pp. 190-191), in which Apatania is one of five genera, all formerly Limnephilid genera.

Like all members of the Limnephilid (Northern case-maker) family, Apataniid caddisfly larvae have: 1) a pair of mesonotal plates while the metanotum is fleshy; 2) a dorsal hump and lateral humps; and 3) a prosternal "horn," a sharp projection at the base of the head (ventral).  We can see those features in the following photos:

However, Apatania is distinct in lacking sa1 sclerites (dark anteromedial spots on the metanotum): rather, it has a transverse row of setae.

Wiggins had pointed this out in 1977 when Apatania was still considered a Limnephilid genus: "Larvae can be distinguished from those of any other limnephilid in North America by absence of the metanotal sa1 sclerites and arrangement of those setae in a continuous transverse band." (Wiggins, p. 198)  Also relevant to this discussion -- in the Apatania illustrations that Wiggins provides (p. 199), we can clearly see that the rear corners of the mesonotal plates are black, as in the photo above, and the ventral apotome is an exact match to that of the larva found yesterday.  It looks like this:

Now let's see what Beaty says about Apatania (genus) incerta (species) in his discussion of Apataniidae ("The Trichoptera of North Carolina," p. 85).

Genus Diagnosis: Mesonotum with two plates; metanotal sa1 sclerites absent; arrangement of sa1 associated setae in a linear transverse row; head oval and with many secondary setae; mandibles usually with uniform scraper blades (not toothed). Larvae collected fall through winter.  Mountains only.

Case: composed of mineral particles and strongly curved, cornucopia-shaped; larger mineral particles laterally.

The genus description is right on -- though I did not try to photograph the mandibles.  And the case description is exact.

I called it "cone-shaped".

(By the way, you can see the "hood" on the case in Wiggins' illustrations.)  Now let's look at Beaty on A. incerta.

A.  incerta -- larvae 6-9 mm; head dark brown to black; nota brownish-black; anterior metanotal plates replaced by row of about 20 setae; legs yellow brown; anal claw lacking well defined accessory teeth.

The colors of the head, nota, and legs are all clear in the live photos that I've provided.  I can count 20-21 setae in the transverse row on the metanotum.  As for the anal claw: it's tiny, and I can not see any accessory teeth.


Exciting!  A new one.  I will add this to the EPT lists provided in earlier entries (9/8 and 10/8).  Apataniidae, Apatania incerta.  Common name: Early Smoky Wing Sedge.  Tolerance value: 0.6.

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