Megarcys signata

• Main Authors: Stewart, Kenneth W., Kondratieff, Boris C.
• Format: Text
• Language: unknown
• Published: Zenodo 2012
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Insecta; Plecoptera; Perlodidae; Megarcys; Megarcys signata; Yukon; Hagen; Chasm; Granite Falls; Peaceful Valley; Chasm Lake; Watson Lake; Whitehorse; Alaska
• Online Access: https://dx.doi.org/10.5281/zenodo.4762538; https://zenodo.org/record/4762538

Megarcys signata (Hagen 1874) (Figs. 2-11, 13, 18, 19, 25, 31, 37, 43, 50, 61, 71, 80, 85 a-b, Table 1) Distribution. Rocky Mountains, New Mexico- Nevada northward to British Columbia and Alaska. Material examined. Colorado: Boulder Co., South Boulder Creek, 3.2 km west of Tolland, 7-VII-1991, B. Kondratieff, R. Durfee, 11♂ (both macropterous and brachypterous), 6♀, 11♀ larvae, 2♂ exuviae; Middle St. Vrain Creek, FR 14 west of Peaceful Valley, 17- VII-1993, B. Kondratieff, B. Painter, 1♂, 2♀ larvae; Gunnison Co., Mosquito Creek/confluence Quartz Creek, Colorado Rd. 76 north of Pitkin, 9-VII-2008, K. Stewart, reared series: 2 reared ♂ with exuviae, 1 reared ♀ with exuvium, 8♂ larvae, 14♀ larvae; Larimer Co., outlet stream of Chasm Lake, Rocky Mountain National Park, El. 3536m, 16-VII-1994, B. Kondratieff, R. Durfee, 2 brachypterous ♂ larvae, 1♀ brachypterous larva. Montana: Gallatin Co., 5.63 km off Trail Creek Rd., 10-6-1987, B. Kondratieff, 2♂, 2♂ larvae, 3♀ larvae, 3♂ exuviae, 2♀ exuviae. Wyoming: Teton Co., Granite Creek, Granite Falls, 8-VII-2001, B. VanWieren, 1♀, 2♀ larvae. Yukon Territory: Alaska Hwy., stream crossing between Watson Lake and Whitehorse, V-1997, P. Niblett, 4♂ larvae, 3♀ larvae. Characters. Head capsule width ♂ 3.24-3.48mm, ♀ 4.14-4.20mm; pronotal width ♂ 2.64-2.76mm, ♀ 3.36- 3.90mm; body length ♂ 16.2-18.5mm, ♀ 25-26mm (Table 1). Color and pigmentation (Figs. 2, 3, 13, 19, 25, 43, 50), lacinia (Fig. 21), and dorsomesal band of erect silky white hairs (Figs. 18, 19) typical of genus and as described by Stewart & Stark (1988, 2002). Wingpads of ♂ and ♀ (Figs. 2, 25) macropterous (or brachypterous in high elevation streams). Gill number and arrangement typical of genus (Fig. 61). Submental gill length ♂ 0.36-0.48mm, ♀ 0.54- 0.60mm; anterior supracoxal gill length ♂ 0.36- 0.42mm, ♀ 0.45-0.0.60mm (shorter in high elevation Chasm Lake outlet stream in Rocky Mountain National Park) (Table 1). Legs (Figs. 6, 31) with setation typical of genus as described by Stewart & Stark (2002).Y-arms of mesosternum meet anterior corners of furcal pits (Figs. 7, 8, 37), typical of genus. Cercal segments ♂ 26 (Table 1), as described by Stewart & Stark (2002) with apical whorl of short setae on cercomeres and dorsal fringe of silky white hairs (Fig. 11). Developing membranous, windsocklike posterior process of male epiproct (Fig.71) evident in late instar individuals, and pointed posteroventrally in lateral view (Fig. 80). Developing female subgenital plate of 8 th sternum (Figs. 50, 85) shallowly notched mesally. Comments. The generic characters proposed by Stewart & Stark (1988, 2002) were further confirmed in these additional larvae examined. Color and pigmentation (Figs. 2, 3, 13, 19, 25, 31, 43, 50) were of a generic pattern that was similar in the other four species examined. The measured gill lengths, and shapes, were variable between left and right sides, individuals, and populations, therefore difficult to compare with the generalized terms “short” and “long” as used by Teslenko (2009) in her descriptions and keys to Palearctic species. Submental (SM) gills (Figs. 8, 61) are not visible from dorsal view; anterior supracoxal (ASC) gills and anterior mesothoracic and anterior metathoracic (AT2, AT3) gills (Figs. 8, 61) are “long” and usually visible in dorsal view. : Published as part of Stewart, Kenneth W. & Kondratieff, Boris C., 2012, Larvae Of The Nearctic Species Of The Stonefly Genus Megarcys Klapálek (Plecoptera: Perlodidae), pp. 16-36 in Illiesia 8 (3) on page 20, DOI: 10.5281/zenodo.4760667 : {"references": ["Hagen, H. A. 1874. Report of the Pseudo-Neuroptera and Neuroptera collected by Lieut. W. L. Carpenter in 1873 in Colorado. In Hayden. Annual Report on the United States Geological and Geological Survey of the Territories, embracing Colorado, being a report of progress of the explorations for the year 1873. Pp: 571 - 606.", "Stewart, K. W. & B. P. Stark. 1988. Nymphs of North American stonefly genera (Plecoptera). Thomas Say Foundation Series, Entomological Society of America, 12: 460 pp.", "Stewart, K. W. & B. P. Stark. 2002. Nymphs of North American stonefly genera (Plecoptera), 2 nd Ed. The Caddis Press, Columbus, Ohio. 510 pp.", "Teslenko, V. A. 2009. Larvae of the Palearctic species of the stonefly genus Megarcys (Plecoptera, Perlodidae). Entomological Review, 89: 815 - 819."]}