Isoperla fulva Claassen 1937

Isoperla fulva Claassen

(Figs. 2f, 8 a-h, 20 f)

Isoperla fulva Claassen 1937, 69:80.

Holotype ♂, Logan River, Cache Co., Utah.

Isoperla fulva: Jewett 1960, 6:159. First California records.

Isoperla fulva: Szczytko & Stewart 1979, 32:67-75. ♂, ♀, larva (reared), ovum.

Material examined. COLORADO: Boulder Co., SF Middle Boulder Creek, TR901, 3 mi (4.8 km) W Hessie, 6 mi (9.6 km) W Eldora, 23/VIII/1997, J. Sandberg, Larvae (reared); Gunnison Co., Beaver Creek, at Beaver Creek Picnic Area near confluence with Gunnison River, 24/V /1997, J. Sandberg, Larvae (reared); Quartz Creek, Pitkin, The Ken & Francine Stewart Cabin, 07/VII/1999, J. Sandberg, ♂ ♀, Larvae (reared); Larimer Co., Cache la Poudre River,, 13/VI /1998, J. Sandberg, ♂ ♀, Larvae; Saguache Co., Cochetopa Creek, Hwy 114 between UU-13 & 14- PP Roads, S of Hwy 50, 06/VI /2003, J. Sandberg, Larvae (reared); OREGON: Douglas Co., Cow Creek, at Quines Creek, 08/IV/1968, S. Jewett Jr., ♂ ♀ not everted (NMNH); Jackson Co., Applegate River, 10 mi (16.1 km) S Ruch, 22/V /1964, J. Schuh, ♂ ♀ (NMNH); Jefferson Co.,?, Palisades State Park, 14/V /1954, S. Jewett Jr., ♂ (NMNH); Klamath Co., Crescent Creek, Rt. 58, 39 mi (62.8 km) E Oakridge, 25/VI /1985, C. & O. Flint, Jr., ♀ (NMNH); Sprague River, near Bly, 02/VI /1972, D, Denning, ♂ (damaged) (NMNH); Wallowa Co., Wallowa River, Wallowa Mts., Johnson Street Park, 02/VII/1948, C. Alexander, ♂ ♀, (poor condition) (NMNH); Wallowa River, Minam, 2700 feet, 21/VII/1929, H. Scullen, ♂ (NMNH); WASHINGTON: Columbia Co., Tucannan River, Hwy 410 (12), 1940 feet, 20/IV/1968, E. Evans, ♂ (NMNH).

Male larva. Body length of mature larva 9–10 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 indistinct, not connected to light frontoclypeus area, median longitudinal light band usually oval, lateral thin arms variable, sometimes directed posterolaterally and extending to antennal bases; posterior ocelli with partially enclosed large light areas along outer lateral margins; interocellar area variable, from completely dark to partially light and completely enclosed by dark pigment, light area not extending past posterior ocelli; occiput with irregular spinulae band extending from below eye to near median epicranial suture, not enclosed completely by dark pigment (Fig. 8a). Lacinia bidentate, total length 688–829 µm (Figs. 2f, 8 e-h, Tables 2-4); submarginal row (A+B) with 2–3 setae, groups A-B interrupted by gap below subapical tooth (SAT) inner margin (Figs. 8 g-h); 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, submarginal seta (A) or broken, and 1 dorsal seta (DS) located below SAT inner margin, partially obstructed by SAT or submarginal setae (B) (Figs. 8 g-h); 1–2 submarginal setae (B) located past SAT inner margin (Fig. 8h); 6–11 marginal setae (C), initially long-stout and widely spaced, last few shorter and closer, blending into and difficult to differentiate from dorsal and ventral surface setae (Fig. 8e); 64–109 ventral surface setae (D) forming dense longitudinal band below submarginal and marginal setae, ending posteriorly at approximately ¾ the inner lacinia margin length, setae closest to inner margin protrude laterally past lacinia margin (Fig. 8f); dorsal surface setae (DSS) forming dense, laterally protruding, longitudinal band on and along inner-lateral margin, ending before posterior-most ventral surface setae (Fig. 8f). Galea with 28–44 setae in thick ventral band, apex with 3–6 setae. Maxillary Palp segments 2–3 with curved, apically pointed setae. Pronotum with median light area bordered by wide dark bands typical of the I. marmorata group; discs each with light rugosites, irregular median dark margins and fine dark clothing setae, lateral margins with broad light bands (Fig. 8b). Meso and metanotum with contrasting pigment pattern and fine dark clothing setae (Fig. 8c). Legs with numerous fine golden clothing setae and scattered erect spines on outer surface of femora, erect spines longest and concentrated on dorsal surface; fine silky setae sparse on dorsal surface of femora, numerous and continuous on tibia (Fig. 20f); tibia with very faint transverse bands near proximal end. Abdominal terga with two distinct longitudinal dark stripes; wide light median longitudinal band bisected with indistinct light brown median pigment band; 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. 8d).

Distribution. Canada: Alberta, British Columbia. USA: Arizona, California?, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming (Szczytko & Stewart 1979). The California listing was not confirmed during this study but adults need to be reared from Eagle Creek in the western Warner Mountains of Modoc County.

Diagnosis. The male larvae of I. fulva are most similar to other western species of the I. marmorata complex. They all share dark pigmented bodies and the pronotum is almost completely dark except for the median light band and lateral margins (Figs. 8, 10, 16 a-d). The lacinia of these species is also similar. The larvae of I. fulva larvae are inseparable from I. roguensis (Figs. 16 a-h & 20n), but both can be distinguished from I. marmorata by the lack of a median longitudinal light band connecting the light M shaped pattern to the unpigmented frontoclypeus (Fig. 8a).

Remarks. This species was not collected during this study from California. Eagle Creek, a Modoc County stream may contain this species; however, to confirm this, rearing is required.