Isoperla miwok Bottorff & Szczytko

(Figs. 2i, 11 a-h, 20 i)

Isoperla miwok Bottorff & Szczytko 1990, 92:287-291. ♂, ♀, larva (reared), ovum.

Material examined. TYPES: I. miwok, Holotype ♂, Allotype ♀, CA: El Dorado Co., 3.3 km NE Michigan Bar bridge, 5.3 km SW Latrobe, Indian Creek, 13/IV/1987 , R. L. Bottorff (NMNH #104427). Additional Specimens. CALIFORNIA: Butte Co., Campbell Creek & tributary, North Table Mountain Wildlife Area, Cherokee Rd, 5 mi (8 km) S Cherokee, 09/II/2007, 17/II/2007 , J. Sandberg, Larvae; 03/III/2007 , J. Sandberg, A. Richards, Larvae; 07/IV/2007, 13/IV/2007 , J. Sandberg, ♀, Larvae (reared); 18/IV/2007 , J. Sandberg, ♂; 02/II/2008, 09/II/2008, J. Sandberg, Larvae; 23/II/2008 , J. Sandberg, D. Pickard, Larvae; 08/III/2008, 17/III/2008, 24/III/2008, 30/III/2008, J. Sandberg, Larvae (reared); Campbell Creek & tributary, North Table Mountain Wildlife Area, Cherokee Rd, 5.6 mi (9 km) S Cherokee, 5- 6/IV/2008 , J. Sandberg, ♂ ♀; 08/IV/2008, J. Sandberg, Larvae; 27/IV/2010 , R. Baumann, B. Kondratieff, J. Sandberg, ♂; 02/ V/2010, J. Sandberg, A. Richards, ♂ ♀, Larvae; 12/III/2011 , J. Sandberg, ♂, Larvae (reared); 27/III/2011 , J. Sandberg, Larvae (reared); Oregon Gulch, Red Bridge at Oregon Gulch Road, Oregon City, 16/III/2008, 22/III/2008 , J. Sandberg, Larvae; 27/IV/2010 , R. Baumann, B. Kondratieff, J. Sandberg, ♂ ♀; 02/ V/2010, J. Sandberg, A. Richards, ♂ ♀, Larvae (reared); El Dorado Co., Tributary of NF Cosumnes River, Union Mine Rd., 3.4 mi (5.5 km) N Nashville at McNulty Mine Rd. crossing, 04/IV/2009 , J. Sandberg, D. Pickard, Larvae; 25/IV/2009 , J. Sandberg, Larvae (reared); Lake Co.,?, S junction Hwy 20 & 53, 22/IV/1955 , S. Hitchcock, Larvae (lacinia mounted – Slide #007) (NMNH) .

Male larva. Body length of mature larva 9–11 mm. Dorsum of head with contrasting pigment pattern and fine light clothing setae, anterior frontoclypeus margin unpigmented; light M shaped pattern anterior to median ocellus variable, usually connected to light frontoclypeus area by an apically narrowed 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 and extending posteriorly to epicranial Y-suture or sometimes open posteriorly and connected to posterior margin of head by thin light longitudinal band; occiput with irregular spinulae band extending from below eye to near median epicranial suture, not enclosed completely by dark pigment (Fig. 11a). Lacinia bidentate, total length 622–888 µm (Figs. 2i, 11e- h, Table 2-4); submarginal row (A+B) with 2–3 setae, groups A-B interrupted by gap below subapical tooth (SAT) inner margin (Fig. 11g); 1 submarginal seta (A) inserted near mid-base of SAT, half as stout at its base as first submarginal (B) seta, plus 1 thin marginal seta (TMS) adjacent to apical tooth (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. 11 g-h); 1–2 submarginal setae (B) located past SAT inner margin (Fig. 11h); 5–7 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. 11e); 7–15 ventral surface setae (D), scattered below marginal setae, ending posteriorly at approximately ¾ the inner lacinia margin length and concentrated in posterior half (Fig. 11f); 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 or near posterior-most ventral surface setae (Fig. 11f); 10–15 minute scale-like spinulae rarely present on and along ventral inner-lateral margin at middle of lacinia. Galea with 12–26 setae in sparse ventral row, apex with 2–4 setae. Maxillary Palp segments 2–3 with curved, apically pointed setae. Pronotum with large median light area bordered by thick dark comma shaped bands (typical of the I. sobria complex) that fade rapidly in alcohol; discs each with fine light clothing setae, except over small light rugosites and lateral margins with broad light bands (Fig. 11 b); Meso and metanotum with contrasting pigment pattern and fine light clothing setae (Fig. 11c). Legs with numerous fine light clothing setae and scattered erect spines on outer surface of femora, erect spines longest and concentrated along dorsal surface; fine silky setae numerous and continuous on dorsal surfaces of femora and tibia (Fig. 20i); distal femora and proximal tibia with faint transverse bands. Abdominal terga with three distinct longitudinal dark stripes; wide median longitudinal light 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 light clothing setae and erect spines scattered dorsally; posterior margin with scattered long and numerous short spines in a concentrated row (Fig. 11d).

Distribution. California: usually non-perennial central Sierra Nevada foothill creeks.

Diagnosis. Male larvae of I. miwok are distinctive among all other California Isoperla species with 2–4 total submarginal (A+B) setae by the single lacinia submarginal (A) seta arising from near the middle of the base of the subapical tooth (Fig. 11h).

Remarks. Isoperla miwok has long antennae and cerci as noted by Bottorff et al. (1990) which often break when collected and pigment patterns that darken or fade when preserved in ethanol. This species was collected with and emerged slightly before I. adunca from non-perennial foothill streams usually containing submerged aquatic plants. In Campbell Creek, Butte County, a large population seems to tolerate the increased organic enrichments supplied by ranging cattle and medium levels of stream bank erosion. Emergence occurred in late March–early May (late May in wetter years).