Isoperla mormona Banks, 1920

Sandberg, John B., 2011, The Isoperla Of California (Plecoptera: Perlodidae); Larval Descriptions And A Key To 17 Western Nearctic Species, Illiesia 7 (22), pp. 202-258 : 234-237

Isoperla mormona Banks

( Figs. 2j , 12 a-h, 20 j)

Isoperla mormona Banks 1920, 64 :332.

Holotype ♀, Vinyard , Utah.

Isoperla mormona: Szczytko & Stewart 1979 , 32:23-27. ♂, ♀, larva (reared), ovum.

Materials Examined. CALIFORNIA: Alameda Co.,?, Sunol Regional Park , 24/IV/1971, D. Denning, ♂ ( NMNH) ; Indian Creek, 1.8 mi (2.9 km) upstream of San Antonio Reservoir , 25-V-2010, Larva ( ABL) ; Butte Co., Big Chico Creek, Hooker Oak Recreation Area Chico , 10/V/1968, E. Evans, ♀ ( NMNH) ; Big Chico Creek, Big Chico Creek Ecological Reserve , N39.86909 W121.70760, near north boundary, 24/V/2009, J. Sandberg, A. Richards, ♂ ♀, Larvae (reared) ; 25/V/2009, J. Sandberg, D. Pickard, Larvae ; Big Chico Creek, Five-Mile Recreation Area, Centennial Ave & Crow Canyon Ct, Chico , (11, 15, 19)/ V/2010, J. Sandberg, ♂ ♀, Larvae (reared) ; Creek?, Richardson Springs , 11/V/1968, E. Evans, D. Maddox, ♂ ( NMNH) ; Mud Creek, Richardson Springs , 15/IV/2010, J. Sandberg, D. Pickard, J. York, Larvae ; El Dorado Co., Deadman Creek, Church Mine Road crossing, 2.45 mi (3.9 km) SE El Dorado, 23/V/2009, J. Sandberg, Larvae (1♂ reared) ; Greenwood Creek, Greenwood Creek Park, Hwy 49 , 4 mi (6.4 km) E Pilot Hill, 16/V/2008, J. Sandberg, ♂ ♀ ; 28/III/2009, Larvae ; 25/IV/2009, Larvae ; 10/V/2009, ♀ ; 16/V/2009, 23/V/2009, ♂, Larvae (reared) ; NF Cosumnes River, Hwy 49 Nashville , 11/VI/1982, 13-19/VI/1982, R. Bottorff, ♂ ♀ ( NMNH) ; NF Cosumnes River, Sweenys, Somerset , 23/VI/1952, R. Bottorff, ♀ ( NMNH) ; Weber Creek, Forni Road bridge crossing Placerville , 16/V/2008, J. Sandberg, ♀ ; Inyo Co.,?, Sawmill, 3800 feet (1158 m), W Hwy 395, 15/VII/1965, A. Sheldon, ♂ ♀ ( NMNH) ; Kern Co., Lucas Creek, Breckenridge Mt FR Rd , 5.7 mi S Hwy 178 nr Democrat Hot Springs , 10/IV/2008, Larvae ( ABL) ; Los Angeles Co., Little Rock Creek, Cheseboro Rd ( Forest Service Rd 5N04 ), 10.5 mi (16.9 km) S Littlerock, 03/VI/2010, Larvae ( ABL) ; Marin Co.,?, Muir Woods, 27/VI/1965, D. Denning, ♂ ♀ ( NMNH) ; Creek?, Near Point Reyes , 11/V/1971, D. Denning, ♂ ( NMNH) ; Paper Mill Creek,?location, 06/VI/1965, S. Jewett Jr., ♀ ( NMNH) ; Modoc Co.,?, 8 mi (12.9 km) NW Fandango Pass, Warner Mts , 11/VII/1967, Adult, E. Evans ( NMNH) ; Thomas Creek, ~ 2.8 mi (4.5 km) below Hwy 299 , 29/VI/2004, Larvae ( ABL) ; Monterey Co., Big Sur River, Pfeiffer Big Sur State Park , 12/VII/1958, C. Alexander, ♀ ( NMNH) ; Napa Co.,?, 7.6 mi (12.2 km) W Hwy 121 on Hwy 128 , 20/VI/1985, C. & O. Flint Jr., Larvae ( NMNH) ; Creek?, Near Glen Ellen , 18/V/1974, D. Denning, ♂ ( NMNH) ; Plumas Co., Grizzly Creek, 2 mi (3.2 km) below Lake Davis Dam , 23/V/2006, J. Sandberg, D. Pickard, J. Slusark, ♂ ♀ ; Spanish Creek, Spanish Creek Campground, 3 mi (4.8 km) N of Keddie, 02/VII/2006, J. Sandberg, J., M., E., and S. Hartway, ♂ ♀, Exuviae ; Spanish Creek, Chandler Road bridge, 13/XI/2007, Larvae ( ABL) ; Sacramento Co., Cosumnes River, Sloughhouse , 31/V/1982, 14/VI/1982, R. Bottorff, ♀ ( NMNH) ; Cosumnes River, Michigan Bar , 06/VII/1982, R. Bottorff, ♂ ♀ ( NMNH) ; San Bernardino Co., Deep Creek, ~ 0.9 mi (1.4 km) above Crab Creek , 03/VI/2009, Larvae ( ABL) ; Mill Creek, ~ 0.3 mi (0.5 km) W Mill Creek Campground , 15/V/2002, Larvae ( ABL) ; SF Santa Ana River, E Barton Flats, 6200 feet (1890 m), San Bernardino Mts ., 3-5/VII/1958, C. Alexander, ♂ ♀ ( NMNH) ; San Mateo Co., Gazos Creek, Gazos Creek Road near Hwy 1 , 10/IV/2007, Larvae ( ABL) ; San Luis Obispo Co., San Simeon Creek, at San Simeon Creek Rd , 22/IV/2009, Larvae ( ABL) ; Santa Cruz Co., San Lorenzo River, HC Redwoods State Park , Hwy 9 , 0.5 mi (0.8 km) S Felton, 24/V/2007, J. Sandberg, Exuviae ; Shasta Co.,?, Burney , 19/VI/1963, C. Quick, ♂ ♀ ( NMNH) ; Burney Creek, ~ 1.7 mi (2.7 km) below Burney Falls, 16/VI/2004, Larvae ( ABL) ; Sierra Co., Little Truckee River, Hwy 89 crossing, 12 mi (19.3 km) S of Sierraville, 21/VII/1950, C. Alexander, ♀ ( NMNH) ; OREGON: Benton Co.,?, 9 mi (14.5 km) W Berry Creek Experimental Station, Corvallis , 07/VI/1968, E. Evans, ♂ ( NMNH) ; Crook Co.,?, Ochoco Forest Campground nr Prineville , 26/VII/1963, J. Baker, ♀ ( NMNH) ; Klamath Co.,?, Klamath Falls, Black Light , 15/VII/1971, J. Schuh, ♀ ( NMNH) ; Umatilla Co., Umatilla River?, near Rieth , 05/VII/1948, C. Alexander, ♂ ♀ ( NMNH) ; WASHINGTON: Yakima Co., Naches River, near Naches , 31/VII/1947, C. Alexander, ♀ damaged ( NMNH) .

Male larva. Body length of mature larva 7–9 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 thin median longitudinal light band, lateral thin arms directed posterolaterally, extending to antennal bases; posterior ocelli with partially enclosed large light areas along outer lateral margins; interocellar area variable, usually partially light, completely enclosed by dark pigment with light area extending to posterior margin of posterior ocelli, or sometimes mostly light and connected to posterior margin of head capsule by a thin median light band; occiput with irregular spinulae band extending from below eye to near median epicranial suture, not enclosed completely by dark pigment ( Fig. 12a ). Lacinia bidentate, total length 525–666 µm ( Figs. 2j , 12 e-h, Tables 2-4 ); submarginal row (A+B) with 4 setae, groups A-B interrupted by gap below subapical tooth (SAT) inner margin ( Fig. 12g ); 1 submarginal seta (A) inserted at base of apical tooth (AT) inner margin, plus 1 thin marginal seta (TMS) adjacent to AT inner margin, sometimes obstructed from view by AT or broken, and 1 dorsal seta (DS) located below SAT inner margin, partially obstructed by SAT ( Figs. 12 g-h); 3 submarginal setae (B) located past SAT inner margin ( Fig. 12h ); 6–9 marginal setae (C), initially long-stout and widely spaced, last few shorter and widely spaced, blending into and difficult to differentiate from dorsal surface setae ( Fig. 12g ); 7–14 ventral surface setae (D) scattered below marginal setae, ending posteriorly at approximately ¾ the inner lacinia margin length and concentrated in posterior half ( Fig. 12f ); dorsal surface setae (DSS) continue from last marginal setae (C) as a single, laterally protruding, submarginal row (sometimes 2–3 setae thick) along inner-lateral margin, ending before posterior-most ventral surface setae ( Fig. 12f ). Galea with 12–17 setae in sparse ventral row, apex with 2–3 setae. Maxillary Palp segments 2–3 with curved, apically pointed setae. Pronotum with median light area bordered (at least partially) by thin, irregular dark bands; discs each with partially enclosed light areas or “windows”, fine dark clothing setae and lateral margins with broad light bands ( Fig. 12b ). Meso and metanotum with contrasting pigment pattern and fine dark clothing setae ( Fig. 12c ). Legs with numerous fine dark clothing setae and scattered erect spines on outer surface of femora, erect spines longest and concentrated on dorsal surfaces; fine silky setae sparse on dorsal surface of femora, numerous and continuous on tibia ( Fig. 20j ); tibia with faint transverse bands near proximal end. Abdominal terga with three distinct longitudinal dark stripes; wide light median longitudinal band bisected with thin dark median longitudinal stripe; lateral pair of dark longitudinal stripes about as wide as median dark stripe, not extending to lateral margins; numerous fine dark clothing setae and erect spines scattered dorsally; posterior margin with scattered long and numerous short spines in a concentrated row ( Fig. 12d ).

Distribution. Canada: British Columbia. USA: Arizona, California, Colorado, Idaho, Montana, New Mexico, Oregon, Utah, Washington, and Wyoming. Mexico: Baja California. Widely distributed throughout California.

Diagnosis. Mature I. mormona male larvae are the smallest western Isoperla species (7–9 mm) and can be separated from other similar species that possess 2–4 submarginal setae (A+B) by having 7–14 ventral surface (D) setae ( Fig. 12f ), fine silky setae sparse on dorsal surface of femora, numerous and continuous on tibia ( Fig. 20j ) and interocellar area partially light ( Fig. 12a ).

Remarks. Isoperla mormona is distributed throughout northern and southern California from perennial and non-perennial streams. In Butte and El Dorado counties, emergence occurred in May–June.

Figures

Figs. 2a-q. Isoperla lacinia habitus, 40x, Bar = 500µm. 2a. I. acula; 2b. I. adunca; 2c. I. baumanni; 2d. I. bifurcata; 2e. I. denningi; 2f. I. fulva; 2g. I. laucki; 2h. I. marmorata; 2i. I. miwok; 2j. I. mormona; 2k. I. muir; 2L. I. pinta; 2m. I. quinquepunctata; 2n. I. roguensis; 2o. I. sobria; 2p. I. sordida; 2q. I. tilasqua.

Figs. 12a-h. Isoperla mormona nymph and ventral maxilla, Greenwood Creek, El Dorado County, CA. Submarginal setae groups A and B, Marginal setae C, Ventral surface setae D, Dorsal surface setae DSS, Dorsal Seta DS, and Thin marginal seta TMS. White bars = 1 mm, 12 e-f 100x, 12g 200x, and 12 h 400x.

Figs. 20a-q. Isoperla front right leg habitus, Larvae, 32–40x, Bar = 1mm. 20a. I. acula; 20b. I. adunca; 20c. I. baumanni; 20d. I. bifurcata; 20e. I. denningi; 20f. I. fulva; 20g. I. laucki; 20h. I. marmorata; 20i. I. miwok; 20j. I. mormona; 20k. I. muir; 20L. I. pinta; 20m. I. quinquepunctata; 20n. I. roguensis; 20o. I. sobria; 20p. I. sordida; 20q. I. tilasqua.