Biosystematics of Eocosmoecus, a new Nearctic caddisfly genus (Trichoptera: Limnephilidae, Dicosmoecinae)

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A new genus Eocosmoecus is erected for two North American species, Drusinus frontalis Banks and Dicosmoecus schmidi Wiggins, most recently classified as the frontalis group of Onocosmoecus; it has become clear that they are not holophyletic with this genus. These two species occur in small spring streams of montane areas in British Columbia, Idaho, Montana, Oregon, and Washington; for the most part they are geographically allopatric. Morphological, biological, and distributional data are summarized. Judging from morphological evidence, the two species are very closely related, but they are unusual among congeneric Trichoptera in constructing markedly different cases in the final instar. E. frontalis construct cases of wood and bark and live on exposed substrates of wood and rocks; final instar larvae of E. schmidi construct cases of rock fragments and burrow in gravel sediments. In one population of E. frontalis in Oregon, final instar larvae constructed cases of fine rock fragments as in E. schmidi, as well as typical cases of wood. Evolutionary implications of these observations are considered. Keys distinguishing Eocosmoecus, Onocosmoecus, and Dicosmoecus are given for adults, pupae, and larvae.

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ELECTRONIC FILE - Zoology: Invertebrates

SWAP (2/19/2016) citation:
Wiggins GB, Richardson JS. 1989. Biosystematics of Eocosmoecus, a new Nearctic caddisfly genus (Trichoptera: Limnephilidae, Dicosmoecinae). [accessed 2015 Jun 1]; Journal of the North American Benthological Society. 8(4):355–369. http://www.jstor.org/stable/1467499?seq=1#page_scan_tab_contents