Isoperla sobria Hagen

Isoperla sobria Hagen

(Figs. 2o, 17 a-h, 20 o)

Isoperla sobria Hagen 1874, 7:577.

Holotype ♀.

Perla ebria Hagen 1874, 7:577. Holotype ♀.

Isoperla sobria: Szczytko & Stewart 1979, 32:49-56. ♂, ♀, larva (reared), ovum.

Material examined. ALASKA: Matanuska - Susitna Border, Montana Creek, Hwy 3 bridge near Montana, 08/VI/2006, J. Sandberg, J. Harrington, D. Pickard, J. Slusark, T. Morman, Female Exuviae; CALIFORNIA: Butte Co., Butte Creek, Cherry Hill Campground (Humboldt Rd) 9 mi (14.5 km) NE Lomo (Hwy 32), 06/I/2007, J. Sandberg, A. Richards, Larvae; 27/I/2007, J. Sandberg, Larva; 03/II/2007, J. Sandberg, A. Richards, Larva; 01/IV/2007, J. Sandberg, Larva; 20/III/2008, J. Sandberg, S. Sandberg, Larvae; 26/IV/2010, R. Baumann, B. Kondratieff, A. Richards, J. Sandberg, J. Slusark, ♂ (reared); Butte Creek, Humboldt Road bridge at Colby/Willow Creeks, 0.25 mi (0.4 km) W Jonesville, 25/V/2008, J. Sandberg, ♂; Colusa Co., Big Springs tributary, Big Springs Picnic Area, Letts Lake, FR 17N02, Mendocino NF, 03/II/2009, J. Sandberg, D. Pickard, Larvae; Lily Pond unmapped outflow, W Lily Pond FR 17N02 crossing, Mendocino NF, 03/II/2009, J. Sandberg, D. Pickard, Larvae; Little Stony Creek, FR 18 N07, 20 mi SW Stonyford, Mendocino NF, 01/II/2009, J. Sandberg, A. Richards, Larvae; Contra Costa Co.,?, Martinez,?/ VI/1910, J. Grundell, ♂ cleared (NMNH); El Dorado Co., Tributary of NF Cosumnes River, above Meiss Ranch, 06/VI/1986, R. Bottorff, Female Larvae, Male Exuviae (mounted lacinia slide # 015) (NMNH); Rubicon River,?location, 05/IX/1954, S. Hitchcock, Larvae (NMNH); Mariposa Co., Tamarack Creek, Yosemite National Park, 6300 feet, 30/V/1955, S. Hitchcock, Larvae (mounted lacinia slide #014) (NMNH); Nevada Co.,?spring, entering Sagehen Creek, 6400 feet, 05/VI/1965, A. Sheldon, Male Larvae (mounted lacinia slide #013) (NMNH); Spring head of Hanging Bog, Sagehen Creek, 6300 feet, 23/V/1966, ♂, 13/IX/1965, A. Sheldon, ♂ ♀ (NMNH); Bog Spring, Sagehen Creek, 22/VI/1966, ♀; 07/VII/1966, A. Sheldon, ♂ (NMNH); Spring Trib, to Sagehen Creek, 30/VI/1965, ♂; 01/VIII/1965, ♂; 11/VIII/1965, ♂ ♀; 26/VIII/1965, ♀; 31/VIII/1965, ♂ ♀; 13/IX/1965, A. Sheldon, ♂ ♀ (NMNH); Sagehen Creek, Sagehen Creek Project, Spring Run, 6400 feet, 02/VI/1965, A. Sheldon, Female larvae (mounted lacinia slide #0102) (NMNH); Sagehen Creek, 6400 feet, 05/VI/1965, Larvae; 24/VI/1965, A. Sheldon, ♂ ♀ (NMNH); Sagehen Creek, 6300 feet, 30/V/1965, ♀; 01/VI/1966, A. Sheldon, ♀ (NMNH); Sagehen Creek, Diversion, 02/VI/1966, ♂; 09/VI/1966, ♂; 11/VII/1966, A. Sheldon, ♀ (NMNH); Sagehen Creek, Station Spring, 25/VII/1966, A. Sheldon, ♂ (NMNH); Sagehen Creek,?location, 19/VI/1985, O. Flint, ♀, Larvae; Placer Co?,?, on Carnelian Bay, Lake Tahoe, 24/VI/1954, S. Hitchcock, ♂ ♀ (NMNH); Plumas Co., Big Grizzly Creek, 0.4 mi (0.6 km) S Beckwourth Rd on Unnamed Rd, 6 mi (9.6 km) E Lake Davis, 30/VI/2006, ♀ (Malaise Trap); 15/XII/2006, J. Sandberg, A. Richards, Larvae; Cow Creek, 2 mi (3.2 km) NE Smith Peak nr intersection with jeep trial, 21/VI/2006, larvae; 30/VI/2006, J. Sandberg, A. Richards, ♀ (Malaise Trap); Freeman Creek, 2 mi (3.21 km) S on Threemile Valley Rd, S Lake Davis, 21/VI/2006, Exuviae; 30/VI/2006, ♂ ♀ (Malaise Trap), J. Sandberg, A. Richards; Mosquito Creek (West Branch), 0.4 mi (0.6 km) E Domingo Springs, 8.1 mi (13.0 km) W of Chester, 04/II/2007, J. Sandberg, Larvae; 22/IV/2007, J. Sandberg, D. Pickard, Larvae (reared); 19/V/2007, J. Sandberg, S. Hassur, ♀, Larvae (reared); 28/V/2007, J. Sandberg, D. Pickard, ♀, Larvae (reared); 13/VI/2007, J. Sandberg, Larvae (reared); 16/IX/2007, J. Sandberg, Larvae; 03/XI/2007, J. Sandberg, Larvae; 17/V/2008, J. Sandberg, Larvae; 13/VI/2008, J. Sandberg, ♂ ♀, Larvae (reared); 20/VI/2008, J. Sandberg, ♂, Larvae (reared); 05/VI/2010, J. Sandberg, Larvae (reared); 03/VII/2010, J. Sandberg, ♂ ♀, Larvae (reared); Spring Trib of Lake Davis (Corral), Feeding SE Lake Davis on Threemile Valley Rd, 29/V/2006, J. Sandberg, D. Pickard, J. Slusark, Larvae (reared); 27/X/2006, J. Sandberg, A. Richards, Larvae; 06/VI/2010, J. Sandberg, J. Slusark, Larvae (reared); 04/VII/2010, J. Sandberg, ♂ ♀, Larvae (reared); Spring Trib of Lake Davis (Moselia), Feeding E Lake Davis, 0.5 mi (0.8 km) E Freeman Cr, 29/V/2006, J. Sandberg, D. Pickard, J. Slusark, ♀, Larvae; 21/VI/2006, J. Sandberg, A. Richards, Larvae; Sierra Co., Weber Lake, Little Truckee River?, Henness Pass Road, 04/VII/1965, P. Arnaud, ♀ (CAS); Shasta Co.,?, Burney Falls, 17/IX/1946, H. Chandler, ♀ (CAS); NF Battle Creek,?location, 04/VII/1953, H. Chandler, ♀ (CAS); Tehama Co., Gurnsey Creek, Gurnsey Creek Campground, Hwy 36 (89), 2.3 mi (3.7 km) N Hwy 32 intersection, 27/I/2007, J. Sandberg, Larva; Tulare Co.,?, Sequoia National Park, Giant Forest, 6400 feet, 19/VI/1963, C. Alexander, ♀ (NMNH); Tuolumne CO., Gaylor Lakes, Yosemite NP East, 1000 feet, 08/VII/1945, H. Chandler, ♀ (CAS); COLORADO: ?County,?River, Longs Peak, 12/VII/1926, E. Vandyke, ♂ ♀ (CAS); IDAHO: Franklin Co.,?, Willow Flat Forest Camp, Cub River Canyon, Wasatch Mts, 4-5/VII/1952, B. Malkin, ♂ (CAS); OREGON: Baker Co., Pine Creek,?location, 26/VI/1948, J. Baker, ♀ (CAS); Benton Co., Oak Creek, Corvallis, 02/IV/1935, R. Dimick, ♂ cleared (NMNH); Oak Creek, 6.75 mi (10.9 km) NW Corvallis, Rt branch Oak Cr., E Patterson Rd., 1.5 mi (2.4 km) N of Fish lab, 700 feet, 16-19/V/1969, C. Kerst, ♂ (NMNH); 16-19/V/1969, C. Kerst, ♂ damaged (NMNH); Clackamas Co., Still Creek, Swim Cr., 15/VI/1947, S. Jewett Jr., ♀ (CAS); Coos Co., Wooden Rock Creek, Pioneer Campground, NFD 240 Rd, 0.2 mi (0.3 km) N NFD 3348 Rd intersection, 19/III/2010, J. Sandberg, Larvae; Deschutes Co., Fall River,?location, 13/VII/1948, S. Jewett Jr., ♂ ♀ (CAS); Fall River, Fall River Campground, Hwy 42 (S Century Dr), 13 mi (20.9 km) E Hwy 97, 28/V/2008, 31/V/2008, J. Sandberg, ♂ ♀, Exuviae, Larvae (reared); Douglas Co., Muir Creek, Muir Camp, Hwy 230 bridge, 13.5 mi (21.7 km) E Hwy 138 intersection, 27/V/2008, 31/V/2008, Larvae (reared); Grant Co?, Lunch Creek, Blue Mountains, 24/VI/1952, B. Malkin, ♀ (CAS); Hood River Co.?,?, Hood River Meadows, Mt Hood, 18/VII/1947, K. Fender, ♀ (CAS);?River, Hood River Meadows, E side of Hood, 4475 feet, 31/VII/1948, C. Alexander, ♀ (NMNH); Klamath Co., Spring Creek, Collier State Park, Hwy 97, 3.7 mi (5.9 km) N Pine Ridge, 12/V/1950, S. Jewett Jr., ♂ ♀ (CAS); Linn Co., Marion Creek, Marion Creek (Lake) Rd at Willis Creek confluence, 08/VI/2011, J. Sandberg, ♂ Exuviae; WASHINGTON: Cowlitz Co., Upper Kalama River,?location, 01/XII/1966, O. Flint, ♂ (NMNH); Pierce Co?, Nisqually River, Mt Rainier NP, 13/VII/1936, E. Vandyke, ♀ (CAS); Skamania Co. Tyee Spring, Meadow Creek Rd, 0.44 mi (0.71 km) N NFD 3065 & NFD 30 Rds, 16/VI/2011, J. Sandberg, ♂ ♀ Exuviae.

Male larva. Body length of mature larva 10–13 mm. Dorsum of head with contrasting pigment pattern and fine dark clothing setae, anterior frontoclypeus margin unpigmented; light M shaped pattern anterior to median ocellus connected to light frontoclypeus area by a median longitudinal light band, its width approximately equal to the posteromedian portion of the light M shaped pattern, lateral arms with irregular margins usually disconnected from median light area, directed posterolaterally, and extending to antennal bases; posterior ocelli with partially enclosed large light areas along outer lateral margins; interocellar area variable, usually partially light and shaped like an inverted V, completely enclosed by dark pigment and not extending past posterior ocelli, sometimes a small spot; occiput with irregular spinulae band extending from below eye to near median epicranial suture, not enclosed completely by dark pigment (Fig. 17a). Lacinia bidentate, total length 901–1265 µm (Figs. 2o, 17e- h, Tables 2-4); submarginal row (A+B) with 5–6 setae, groups A-B interrupted by gap below subapical tooth (SAT) inner margin (Fig. 17g); 3–4 submarginal setae (A) in a close set row beginning at base of apical tooth (AT), ending before reaching SAT inner margin, plus 1 thin marginal seta (TMS) adjacent to AT inner margin, sometimes obstructed from view by AT, submarginal setae (A), or broken, and 1 dorsal seta (DS) located below SAT inner margin, partially obstructed by SAT; 2 submarginal setae (B) located past SAT inner margin (Figs. 17 g-h); 10–17 marginal setae (C), initially longstout and widely spaced, sometimes several setae near end of row arranged in pairs protruding at dorsal and ventral angles, last few shorter and closer, blending into and difficult to differentiate from dorsal surface setae (Fig. 17e); 21–58 ventral surface setae (D) scattered below submarginal and marginal setae, ending posteriorly at approximately ¾ the inner lacinia margin length, occasionally a few setae located below submarginal row striated (Fig. 17f); dorsal surface setae (DSS) forming dense, laterally protruding, longitudinal band, concentrated at junction with marginal setae (C), ending at approximately ½ or a little more the lacinia length (Fig. 17e). Galea with 12–23 setae in sparse ventral row, apex with 2 setae. Maxillary Palp segments 2–3 with curved, apically pointed setae (Inset, Fig. 17e). Pronotum with large median light area bordered thick dark comma shaped bands typical of the I. sobria complex, a range of irregular shaped faded light brown areas usually present between the dark commas and entirely covered by fine dark clothing setae, lateral margins with broad light bands (Fig. 17b). Meso and metanotum with contrasting pigment pattern and fine dark clothing setae (Fig. 17c). Legs with numerous fine golden clothing setae and scattered erect spines on outer surface of femora, erect spines longest and concentrated along dorsal surfaces; fine silky setae sparse on dorsal surface of femora, numerous and continuous on tibia (Fig. 20o); distal femora and proximal tibia with distinct transverses bands. Abdominal terga with three distinct longitudinal dark stripes; wide light median band bisected with irregular shaped, dark median longitudinal stripe; lateral pair of dark longitudinal stripes about twice as wide as median dark stripe, usually not extending to lateral margins; numerous fine light clothing setae and erect spines scattered dorsally; posterior margin with scattered long and numerous short spines in a concentrated row (Fig. 17d).

Distribution. Canada: Alberta, British Columbia and Yukon territory; USA: Alaska, Arizona, California, Colorado, Idaho, Montana, New Mexico, Nevada, Oregon, Utah, Washington, and Wyoming. In northern California, widely distributed at higher elevations.

Diagnosis. Mature male larvae of I. sobria are distinctive with the following characters: the lacinia submarginal row (A) has 3–4 close set setae (Figs. 17e, g-h), the completely enclosed inverted V shaped interocellar light area does not extend past posterior ocelli (Fig. 17a), and basal segments 2–3 of the maxillary palpi have long, thin apically pointed setae (Fig. 17a Inset). The interocellar light area was sometimes only a very small spot. It shares a similar dark comma shaped pronotal pigment pattern with the other species in the I. sobria complex (Figs. 5b, 11b, 17b, 19b). Only I. miwok lacked the multiple submarginal setae (A) character (Figs. 11e, g-h).

Remarks. The abdominal pigment stripes of some male and female larvae faded quickly in ethanol and the abdomen became completely dark, losing the light longitudinal stripes. Emergence was slightly extended and occurred in May–July. Adult females had slightly longer subgenital plates than what is illustrated (Fig. 89, Szczytko & Stewart 1979). The typical I. sobria subgenital plate had nearly parallel lateral margins, extended posteriorly to nearly the mid length of abdominal sternite nine, and the apical margin was broadly rounded.

There were observations which may extend the ranges of submarginal lacinia setae, but could not be confirmed with reared and associated specimens. One I. sobria male larva from Williams Fork, Grand County, Colorado, four larvae from Rio Fernando de Taos, Taos County, New Mexico, and one exuviae from Tyee Spring, Skamania County, Washington, had two close set lacinia submarginal (A) setae. This character would overlap with the lower range observed for I. tilasqua (Table 2). Another male larva from Marion Creek, Linn County, Oregon, possessed 5 lacinia submarginal (A) setae, and two submarginal (B) setae. However, all the above male larvae were identified as I. sobria because they possessed long, thin, apically pointed setae on the maxillary palp basal segments 2–3 and inverted V shaped light interocellar marks.