Caddisflies of the Yukon - Department of Biological Sciences ...

816 G.B. Wiggins and C.R. Parker
The longicornis species group comprising M. nigra, longicornis, and interjectus
(Yamamoto and Ross 1966) is apparently of Palaearctic origin. Separation between M. longicornis
and interjectus was probably by vicariant speciation of a continuous circumboreal
ancestral range brought about by separation of Asia and North America.
Note 6. Grammotaulius alascensis Schmid (84)
Grammotaulius subborealis Schmid 1964, new synonymy
These 2 taxa, together with G. signatipennis McLachlan, constitute a complex in which
identification is rendered all the more difficult by the fact that no explicit diagnosis has been
proposed to distinguish one from another. Because a series of Yukon specimens (Dempster
Hwy. km 105, nr. Blackstone R., 30.vii.1979, ROME #791183, 19 males) shows characters
intermediate between those illustrated for males of G. alascensis and G. subborealis (Schmid
1964, figs. 6 –13), the latter name is placed here as a junior subjective synonym under
G. alascensis which has page priority. In the characters illustrated by Schmid for the females,
the pair of slender membranous lobes arising from the posterodorsal margin of segment
IX + X was interpreted inconsistently (Schmid 1964, figs. 4, 5): in G. alascensis the slender
lobe is shown as an appendage of a sclerotized rounded lobe at the base of the anal tube; in
G. subborealis the slender lobe is shown correctly as a median structure separate from the
sclerotized lobe. These paired membranous lobes are actually eversible, and appear in
genitalic preparations of Grammotaulius and many other Limnephilidae in variable conditions
of eversion; in Schmid’s figures of G. signatipennis (1950a, figs. 52 – 54) they do not
appear at all, as is often the case, although the lobes are extended in other cleared specimens
of this species.
In this emended sense, G. alascensis appears to be the North American sister species of
G. signatipennis. Our material of G. signatipennis is not extensive, but the principal
distinguishing character of the males is evidently the posteroventral edge of the superior
appendages, which is very heavily sclerotized, darkened, and rather linear in G. alascensis,
but more rounded and less sclerotized in G. signatipennis. In some specimens of the latter
species, the posteroventral margin of the superior appendage is somewhat more heavily
sclerotized than illustrated (Schmid 1950a, fig. 50). The intermediate appendages in our
North American material show considerable variation, as was illustrated by Schmid. We
have seen a specimen of G. alascensis from the Hudson Bay coastline of the Northwest
Territories (Eskimo Point, 30.ix.1939, CNCI). From all of this, G. alascensis can be regarded
as a highly variable North American species. We do not have sufficient material to assess
variation for a consistent character separating females of these 2 species.
We are advised by O.S. Flint that the Alaskan specimens attributed to G. signatipennis
McLachlan (Flint 1964: Nunivak Is., USNM) are in fact G. alascensis Schmid. However,
G. signatipennis must remain as part of the North American fauna because we have found
a single male from the Yukon (Dawson, Moose Cr., CNCI) in which the genitalic structure
is typical for this species. The forewings show the typical markings only faintly, which we
attribute to the rather teneral condition of the specimen.
Note 7. Limnephilus diphyes McLachlan (96)
This species is recorded here for the first time from North America; diagnostic
characters in genitalic morphology are illustrated (Figs. 10, 11; and also by Malicky 1983,
pp. 191 and 200). The original description by McLachlan (1880) provides a good account
of the general morphology. Limnephilus diphyes appears to belong to the sitchensis group
(Schmid 1955), and can be distinguished from the other species by the prominent notch in
the superior appendages of the male.