Isoperla bifurcata Szczytko &amp; Stewart
Creators: name: Sandberg, John B.
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Plecoptera
Perlodidae
Isoperla
Isoperla bifurcata

description: <i>Isoperla bifurcata</i> Szczytko &amp; Stewart (Figs. 2d, 6 a-h, 20 d) <i>Isoperla bifurcata</i> Szczytko &amp; Stewart 1979, 32:80-84, 86. <i>Isoperla bifurcata</i>: Bottorff et al. 1990, 92:299-302. Larva (reared). <i>Isoperla baumanni</i> Szczytko &amp; Stewart 2002, 128:2-3. Larva (not reared) = <i>I. bifurcata</i>. <b>Material examined.</b> TYPES: <i>I. bifurcata</i>, Holotype &amp;male;, OR: <b>Union Co.</b>, ~ 6 mi (9.7 km) E Medical Springs, DFTM Proj., Lick Creek, 23/VII/1975, D. Dunster (NMNH #76343); Allotype &amp;female;, same location and collector, 30/VI/1976 (NMNH); Paratype &amp;male; &amp;female;, same location and collector as Holotype, 23/VII/1975 (NMNH). <b>Additional Specimens.</b> CALIFORNIA: <b>Butte Co</b>., Butte Creek, Butte Meadows Campground, Humbug Rd., Butte Meadows, 30/III/2007, J. Sandberg, Larvae; Butte Creek, Cherry Hill Campground, Humbug Rd., 9 mi (14.5 km) NE Lomo (Hwy 32), 18/II/2007, J. Sandberg, D. Pickard, Larvae. <b>El Dorado Co</b>., NF Cosumnes River, Headwaters below Singleton Springs, E Grizzly Flat, 22/VI/1987, R. Bottorff, Larvae (NMNH); NF Cosumnes River, Headwaters below Singleton Springs, E Grizzly Flat, 22/VI/1987, R. Bottorff, Larvae (CAS). <b>Fresno Co</b>., Huntington Lake, 07/VII/1919, F. Blasdell, &amp;male; (NMNH). <b>Plumas Co</b>., Domingo Spring, Domingo Springs Campground, 8.5 mi (13.7 km) NW Chester on Old Red Bluff Rd., 12/VIII/2006, J. Sandberg, J. Slusark, Larvae; 01/X/2006, J. Sandberg, &amp;male; &amp;female;, Larvae (mature and early instar); 10/XII/2006, Larvae; 20/I/2007, Larvae; 04/II/2007, Larvae; 24/III/2007, Larvae; 22/IV/2007, Larvae (reared); 06/V/2007, J. Sandberg, D. Pickard, Larvae; 19/V/2007, J. Sandberg, S. Hassur, Larvae (reared); 28/V/2007, J. Sandberg, D. Pickard, Larvae (reared); 09/VI/2007, J. Sandberg, A. Richards, &amp;male;, Larvae (reared), Exuviae; 13/VI/2007, J. Sandberg, &amp;male; &amp;female;, Larvae (reared); 17/VI/2007, &amp;male; &amp;female;; 07/VII/2007, &amp;male; &amp;female;; 01/VIII/2007, &amp;female;, Larvae; 16/IX/2007, &amp;male; &amp;female;, Larvae; 21/IX/2007, &amp;male; &amp;female;, Larvae; 30/IX/2007, &amp;female;; 03/XI/2007, &amp;male; &amp;female;, Larvae; 20/V/2008, J. Sandberg, D. Pickard, Larvae; 17/V/2008, Larvae; 13/VI/2008, &amp;male; &amp;female;; 20&amp; 22/VI/2008, &amp;male; &amp;female;; 06/IX/2008, &amp;male; - &amp;female;; 05/VI/2010, Larvae (reared); 03/VII/2010, &amp;male;; Mosquito Creek (East Branch), 0.6 mi (1 km) E of Domingo Springs, 7.9 mi (12.7 km) W of Chester, 04/II/2007, J. Sandberg, Larvae; 01/IV/2007, Larvae; Mosquito Creek (West Branch), 0.4 mi (0.6 km) E of Domingo Springs, 8.1 mi (13.0 km) W of Chester, 04/II/2007, J. Sandberg, Larvae; 24/III/2007, 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, &amp;male;, Larvae (reared); 13/VI/2007, J. Sandberg, &amp;male; &amp;female;, Larvae (reared); 01/VIII/2007, Larvae; 11/VIII/2007, Larvae; 16/IX/2007, Larvae; 21/IX/2007, Larvae; 03/XI/2007, Larvae; 17/V/2008, Larvae; 13/VI/2008, Larvae (reared); 20/VI/2008, &amp;male; &amp;female;, Larvae (reared); 05/VI/2010, Larvae; 03/VII/2010, &amp;male; &amp;female;. <b>Siskiyou Co</b>., Big Springs Creek, Big Springs Park, Nixon Rd., Mt. Shasta, 13/V/2007, J. Sandberg, D. Pickard, Larvae. <b>Tehama Co</b>., Spring Trib of Gurnsey Creek, Gurnsey Creek Campground, Hwy 36, 2.3 mi (3.7 km) N Hwy 32 Intersec., 26/IV/2010, R. Baumann, B. Kondratieff, A. Richards, J. Sandberg, J. Slusark, Larvae (reared). <b>Trinity Co</b>.,?, Carrville,?/ VI/1913, E.C. VanDyke, &amp;male; &amp;female; (CAS). <b>Tulare Co</b>., Marble Fork Kaweah River, Sequoia Nat. Pk., 24/VII/1907, J. Bradley, &amp;male; (NMNH). OREGON: <b>Union Co</b>., Lick Creek, about 6 mi (9.6 km) E Medical Springs, 30/VI/1976, D. Dunster, &amp;female; (NMNH). <b>Male larva. Body</b> length of mature larva 9–11 mm. <b>Dorsum of head</b> 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 broad median longitudinal light band, lateral thin arms directed posterolaterally, and extending to antennal bases; posterior ocelli with completely enclosed small light areas along outer lateral margins; interocellar area partially light and variable, from completely enclosed by dark pigment to open posteriorly and connected to light area below occipital spinulae band; occiput with irregular spinulae band extending from below eye to near median epicranial suture, enclosed by dark and light brown pigment (Fig. 6a). <b>Lacinia</b> bidentate, total length 666–967 µm (Figs. 2d, 6e- h, Tables 2-4); submarginal row (A+B) with 2–4 setae, groups A-B interrupted by gap below subapical tooth (SAT) inner margin (Figs. 6 g-h); 1–2 submarginal setae (A) the first inserted at base of apical tooth (AT) inner margin, the second when present, located between SAT and AT inner margins, 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 or submarginal setae (B) (Figs. 6 g-h); 1–2 submarginal setae (B) located past SAT inner margin (Figs. 6 g-h); 8–11 marginal setae (C) initially long-stout and widely spaced, last few shorter and closer, blending into and difficult to differentiate from dorsal surface setae (Fig. 6e); 17–38 ventral surface setae (D) scattered below submarginal and marginal setae ending posteriorly at approximately ¾ the inner lacinia margin length (Fig. 6f); dorsal surface setae (DSS) forming dense, laterally protruding, longitudinal band on and along inner-lateral margin, ending before posterior-most ventral surface seta (Fig. 6f). <b>Galea</b> with 37–50 setae in thick ventral band, apex with 4–6 setae. <b>Maxillary Palp</b> segments 2–3 with curved, apically pointed setae. <b>Pronotum</b> generally light brown, median light area bordered laterally by dark brown pigment and light rugosites; discs each with thin, dark brown comma shaped areas near lateral margins and fine dark clothing setae, lateral margins with broad light bands (Fig. 6b). <b>Meso and metanotum</b> with contrasting pigment pattern and fine dark clothing setae (Fig. 6c). <b>Legs</b> with numerous fine dark 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 but not continuous on tibia (Fig. 20d); tibia with very faint transverse bands near proximal end. <b>Abdominal terga</b> with two distinct longitudinal dark stripes; wide light median longitudinal band occasionally appears bisected by muscle attachment scars; lateral pair of dark longitudinal stripes usually 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. 6d). <b>Distribution.</b> Northern California (Sierra Nevada high elevation springs and creeks), Idaho, and Oregon. <b>Diagnosis.</b> Male larvae of <i>I. bifurcata</i> are most similar to <i>I. acula</i> and can be separated by having fine silky setae sparse on dorsal surface of femora, numerous but not continuous on tibia (Fig. 20d), and abdomen without a distinct median dark stripe (Fig. 6d). <b>Remarks.</b> This species was the lone <i>Isoperla</i> species or occurred with either <i>I. baumanni</i> or <i>I. sobria</i> in small to large, mid-elevation spring creeks in the Sierra Nevada range of California. Emergence was extended at Domingo and Mosquito Springs, Plumas County, and occurred in May–October. An extended summer-fall emergence was also observed for <i>I. laucki</i>.
description: Published as part of <i>Sandberg, John B., 2011, The Isoperla Of California (Plecoptera: Perlodidae); Larval Descriptions And A Key To 17 Western Nearctic Species, pp. 202-258 in Illiesia 7 (22)</i> on pages 219-222, DOI: 10.5281/zenodo.4760320
description: {"references": ["Szczytko, S. W. &amp; K. W. Stewart. 1979. The genus Isoperla (Plecoptera) of western North America; Holomorphology and systematics, and a new", "Bottorff, R. L., S. W. Szczytko, &amp; A. W. Knight. 1990. Descriptions of a new species and three incompletely known species of western Nearctic Isoperla (Plecoptera: Perlodidae). Proceedings of the Entomological Society of Washington, 92 (2): 286 - 303.", "Szczytko, S. W. &amp; K. W. Stewart. 2002. New larval descriptions of 5 western Nearctic Isoperla: I. roguensis, I. katmaiensis and I. baumanni and further descriptions of the male and ova of I. decolorata (Plecoptera: Isoperlinae). Transactions of the American Entomological Society, 128 (1): 1 - 22."]}