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Alpine spiders and harvestmen of Mount Rainier, Washington, U.S.A.: taxonomy and bionomics

Crawford, Rodney L., Edwards, John S.
Canadian journal of zoology 1989 v.67 no.2 pp. 430-446
Opiliones, Pardosa, arthropods, females, males, meadows, new combination, pitfall traps, shrubs, species diversity, Cascade Mountain region, Washington (state)
Resident spiders and harvestmen were collected (largely by pitfall trap) at eight sites from 1930 to 3230 m elevation on Mount Rainier (4392 m), Cascade Mountains, ranging in environment from subalpine heath shrub meadow to essentially unvegetated aeolian zone. Records and taxonomic and ecological notes are given for the 31 species taken. Two new linyphiid spiders are described in the genera Scotinotylus and Meioneta; Scotinotylus autor (Chamberlin) and Coreorgonal petulcus (Millidge) are proposed as new combinations. The female of Scotinotylus bicavatus Millidge is redescribed and a description of the male is given, with a report of a gynandromorph specimen and new synonymy of Scotinotylus bipoculatus Millidge. Several other linyphiid species are illustrated. Variation is discussed in the linyphiids Erigone paradisicola Crosby and Bishop, S. bicavatus, and Tennesseellum formicum Emerton and the gnaphosid Micaria constricta Emerton. Included are the first valid North American records of the linyphiid Walckenaeria vigilax (Blackwall) and the first United States records of the phalangiid harvestman Liopilio glaber Schenkel. Samples from 1930 to 2250 m showed similar species richness; above 2250 m, numbers of species decreased but abundance of trapped individuals did not. At the highest site, 3230 m, two species exploit windblown arthropod fallout: the nocturnal L. glaber and the diurnal lycosid spider Pardosa rainieriana Lowrie and Dondale.