Isoperla of

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 : 209-210

Key to the Isoperla of California (including I. muir and I. tilasqua )

Mature Male Larvae

1 Lacinia submarginal setae ( Fig. 1a , Fig. 4g ) arranged in a close set row, extending past the subapical tooth (SAT) inner margin before the first gap between setae occurs ( Fig. 4h ) …..………………….…………………...... I. adunca

1’ Lacinia submarginal row variable, group (A) setae a close set row, not extending past SAT inner margin ( Figs. 5g , 17g & 19g ); submarginal row continuous but setae separated by gaps as wide or wider than the width of setae at bases ( Fig. 13g ); or submarginal row interrupted by large gap between groups A & B ( Figs. 3g , 6-12g , 14-16g & 18g ) .......................................................................... 2

2 Lacinia submarginal row (A) with 2–7 closely spaced setae ( Figs. 5 g-h, 17g-h & 19g-h) omitting thin marginal seta (TMS); pronotum with thick comma shaped dark pigment bands near lateral margins of discs ( I. sobria complex except I. miwok ) ( Figs. 5b , 17b & 19b ) ................................................ 3

2’ Lacinia submarginal row (A) with 1 or 2 widely spaced setae ( Figs. 3 g-h, 6-16g-h & 18g-h) omitting (TMS); pronotum with ( I. miwok ) or without comma shaped pigment bands ……… 5

3 Lacinia submarginal row (A) with 5–7 closely spaced setae ( Figs. 5 g-h); maxillary palp segments 2–3 with curved apically rounded setae ( Fig. 5e Inset); irregular shaped interocellar light area completely enclosed by dark pigment and known only from Domingo Spring, Plumas County, California …………………………….. I. baumanni

3’ Lacinia submarginal row (A) with 2–5 closely spaced setae ( Figs. 17 g-h, 19g-h); basal segments 2–3 of maxillary palpi with long, thin, apically rounded or pointed setae; interocellar light area either enclosed or not completely enclosed by dark pigment; variable distribution ..…….…… 4

4 Basal segments 2–3 of maxillary palpi with long, thin, apically pointed setae ( Fig 17e Inset); interocellar light area usually an inverted V shape, completely within the three ocelli and enclosed by dark pigment ( Fig. 17a ); width of median longitudinal light band connecting light M shape to frontoclypeus approximately equal to posteromedian portion of light M shape ( Fig. 17a ) ……………………..…………………....… I. sobria

4’ Basal segments 2–3 of maxillary palpi with long, thin, apically rounded setae ( Fig. 19e Inset); interocellar light area not an inverted V shape, usually extending past posterior ocelli to median posterior head capsule light area ( Fig. 19a ); width of median longitudinal light band connecting light M shape to frontoclypeus approximately half that of posteromedian portion of light M shape ( Fig. 19a ) ….................................. I. tilasqua

5 Lacinia submarginal row (B) with 5–7 setae ( Fig. 13g ); first marginal seta (C) located under flaplike subapical tooth (SAT) basal inner margin ( Fig. 13h ), dorsal seta (DS) at base of SAT absent ………………………………………............. I. muir

5’ Lacinia submarginal row (B) with 1–3 setae; first marginal seta (C) not under flap-like SAT basal inner margin; DS at base of SAT present ( Figs. 3 gh, 6-12g-h, 14-16g-h & 18g-h) ….……………..…. 6

6 Lacinia with first (closest to AT inner margin) submarginal seta (A) inserted closer to middle of subapical tooth base than to apical tooth inner margin ( Figs. 11 g-h) …………...………. I. miwok

6’ Lacinia with first submarginal seta (A) inserted closer to base of apical tooth inner margin ( Figs. 3 g-h, 6-10g-h, 12g-h, 14-16g-h & 18g-h) …......... 7

7 Lacinia with 1–2 submarginal setae (A) less than half as stout at base as largest marginal setae (C), longitudinal striations weak or absent ( Figs. 14 gh); pronotum with checkerboard pigment pattern ( Fig. 14b ) ....................................................... I. pinta

7’ Lacinia with 1–2 submarginal setae (A) half to nearly as stout at base as largest marginal setae (C), longitudinal striations usually present ( Figs. 3 g-h, 6-10g-h, 12g-h, 15-16g-h & 18g-h); pronotum without checkerboard pigment pattern ( Figs. 3a , 6-10a , 12a , 15-16a & 18a ) ….....................………. 8

8 Lacinia without dorsal surface setae (DSS), at most the last few marginal setae (C) form a short dorsal row ( Fig. 7f - arrow); ventral surface setae (D) concentrated on apical half, few posteriorly ……………………………………..….... I. denningi

8’ Lacinia with dorsal surface setae (DSS) forming a long single row or dense, laterally protruding longitudinal band ( Figs. 3f , 6f , 8-12f , 15-16f & 18f ); ventral surface setae (D) scattered below marginal and submarginal setae or forming a dense longitudinal band, sometimes concentrated in posterior half …………………………………….. 9

9 Lacinia with 7–41 ventral surface setae (D) scattered below marginal or submarginal setae ( Figs. 3f , 6f , 9f & 12f ) …………………….....…… 10

9’ Lacinia with 41–110 ventral surface setae (D) forming dense longitudinal band below marginal or submarginal setae ( Figs. 8f , 10f , 15-16f & 18f ) ….………………...………………...……………….13

10 Lacinia with 7–14 ventral surface setae (D) ( Figs. 9f , 12f ) ….....…..…...……………...…..……..….… 11

10’ Lacinia with 17–41 ventral surface setae (D) ( Figs. 3f , 6f ) ……................……………........………..… 12

11 Fine silky setae sparse on dorsal surfaces of femora and tibia ( Fig. 20g ); interocellar area completely dark ( Fig. 9a ); length 9–10 mm ….…………………………………………. I. laucki

11’ Fine silky setae sparse on dorsal surface of femora, numerous and continuous on tibia ( Fig. 20j ); interocellar area partially light ( Fig. 12a ); length 7–9 mm ………….....…….…… I. mormona

12 Fine silky setae numerous and continuous on dorsal surfaces of femora and tibia ( Fig. 20a ); abdomen with median longitudinal thin dark pigment band ( Fig. 3d ) ………..…….…… I. acula

12’ Fine silky setae sparse on dorsal surface of femora, numerous but not continuous on tibia ( Fig. 20d ); abdomen without median longitudinal dark pigment band ( Fig. 6d ) ………... I. bifurcata

13 Pronotal discs mostly dark, each usually with small, light, reticulate markings along median dark pigment margins ( I. marmorata complex) ( Figs. 8a , 10a & 16a ) …….....………………….…. 14

13’ Pronotal discs patterned, each with variable central light areas generally enclosed by dark pigment ( Figs. 15a , 18a ) ..……………………… 15

14 Dorsal head capsule light M shaped pattern variable, usually not connected to light frontoclypeus area by light longitudinal median band ( Figs. 8a , 16a ) .............. I. fulva & I. roguensis

14’ Dorsal head capsule light M shaped pattern variable, usually connected to light frontoclypeus area by light longitudinal median band ( Fig. 10a ) ………………….....…………….…… I. marmorata

15 Fine silky setae numerous and continuous on dorsal surfaces of femora and tibia ( Fig. 20m ); faint M shaped light pattern on dorsum of head completely enclosed by dark pigment ( Fig. 15a ); pronotum pattern variable with small to large irregular shaped window-like light areas on each disc (small in Fig. 15b ), specimens with large window like light areas usually partially open along inner margins …..…… I. quinquepunctata

15’ Fine silky setae sparse on dorsal surface of femora, numerous and continuous on tibia ( Fig. 20p ); M shaped light pattern on dorsum of head connected to unpigmented frontoclypeus by median light band ( Fig. 18a ); pronotum pattern less variable, with large irregular shaped window-like light areas on each disc ( Fig. 18b ), window-like light areas enclosed by dark pigment along inner margins.…………………... I. sordida

Figures

Fig. 1. Isoperla baumanni left ventral maxilla, abdominal sternites, and head, Domingo Spring, Plumas County, CA. 1a. Submarginal row groups (A) and (B), Marginal row (C), Ventral surface setae (D), Dorsal surface setae (DSS) not illustrated, Thin marginal seta (TMS), and Dorsal seta (DS) not included in submarginal row counts (Table 1). Maxilla measurements (red lines): Apical tooth length (ATL), Subapical tooth length (STL), Apical palm width (PWA), Palm angle (PA), Palm length (PL), Basal palm width (PWB), Galea length (GL), and Palp segment lengths (PL 1–5). 1b. Male and 1c. Female sterna. 1d. Dorsal head capsule: Anterior frontoclypeus area (a), Light M shaped pattern (b) and median longitudinal band (2 arrows), Lateral arms (c), Outer posterior ocellus light area (d), interocellar area (e) and length (arrow), and Epicranial suture (f). Bars = 1 mm.

Figs. 4a-h. Isoperla adunca nymph and ventral maxilla, Campbell Creek, Butte County, CA. Submarginal setae groups A and B, Marginal setae C, and Ventral surface setae D. White bars = 1 mm, 4e-f 100x, 4g 200x, and 4h 400x.

Figs. 5a-h. NEW DESCRIPTION of Isoperla baumanni nymph and ventral maxilla, Domingo Spring, Plumas County, CA. Submarginal setae groups A and B, Marginal setae C, Ventral surface setae D, and Dorsal surface setae DSS. Fig. 5e Inset: Maxillary palp segment 2 with apically rounded long thin setae, 400x. White bars = 1 mm, 5e-f 100x, 5g 200x, and 5h 400x.

Figs. 17a-h. Isoperla sobria nymph Fall River, Deschutes County, OR and ventral maxilla, Mosquito Spring Creek, Plumas County, CA. Submarginal setae groups A and B, Marginal setae C, Ventral surface setae D, Dorsal surface setae, Dorsal seta DS, and Thin marginal seta TMS. White bars = 1 mm, 17e-f 100x, 17g 200x, and 17h 400x.

Figs. 19a-h. Isoperla tilasqua nymph and ventral maxilla, Meacham Creek, Umatilla County, OR. Submarginal setae groups A and B, Marginal setae C, Ventral surface setae D, and Dorsal surface setae DSS. Fig. 5e Inset: Maxillary palp segment 3 with apically rounded long thin setae, 400x. White bars = 1 mm, 19e-f 100x, 19g 200x, and 19h 400x.

Figs. 13a-h. Isoperla muir nymph and ventral maxilla, Muir Creek, Douglas County, OR. Submarginal setae groups A and B, Marginal setae C, Ventral surface setae D, and Dorsal surface setae DSS. White bars = 1 mm, 13e-f 100x, 13g 200x, and 13h 400x.

Figs. 3a-h. Isoperla acula nymph and ventral maxilla, Deadman 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, 3e-f 100x, 3g 200x, and 3h 400x.

Figs. 6a-h. Isoperla bifurcata nymph and ventral maxilla, Mosquito Spring, Plumas 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, 6e-f 100x, 6g 200x, and 6h 400x.

Figs. 7a-h. Isoperla denningi nymph, Roblar Creek, San Diego County and ventral maxilla, Jamala Creek, Santa Barbara County, CA. Submarginal setae groups A and B, Marginal setae C, Ventral surface setae D, Dorsal seta DS, and Thin marginal seta TMS. White bars = 1 mm, 7e-f 100x, 7g 200x, and 7h 400x.

Figs. 8a-h. Isoperla fulva nymph and ventral maxilla, Beaver Creek, Gunnison County, CO. 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, 8e-f 100x, 8g 200x, and 8h 400x.

Figs. 9a-h. Isoperla laucki nymph and ventral maxilla, Dragsaw Spring, Humboldt 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, 9e-f 100x, 9g 200x, and 9h 400x.

Figs. 10a-h. Isoperla marmorata 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, and Dorsal seta DS. White bars = 1 mm, 10e-f 100x, 10g 200x, and 10h 400x.

Figs. 11a-h. Isoperla miwok nymph and ventral maxilla, Tributary of Campbell Creek, Butte County, CA. Submarginal setae groups A and B, Marginal setae C, Ventral surface setae D, Dorsal surface setae DSS, Dorsal seta DS, Thin marginal seta TMS. White bars = 1 mm, 11e-f 100x, 11g 200x, and 11h 400x.

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. 14a-h. Isoperla pinta nymph and ventral maxilla, Butte Creek, Butte County, CA. Submarginal setae groups A and B, Marginal setae C, Ventral surface setae D, and Dorsal surface setae DSS. White bars = 1 mm, 14e-f 100x, 14g 200x, and 14h 400x.

Figs. 15a-h. Isoperla quinquepunctata nymph and ventral maxilla, Butte Creek, Butte County, CA. Submarginal setae groups A and B, Marginal setae C, Ventral surface setae D, Dorsal surface setae, and Thin marginal setae TMS. White bars = 1 mm, 15e-f 100x, 15g 200x, and 15h 400x.

Figs. 16a-h. Isoperla roguensis nymph and ventral maxilla, Butte Creek, Butte County, CA. Submarginal setae A and B, Marginal setae C, Ventral surface setae D, and Dorsal surface setae DSS. White bars = 1 mm, 16e-f 100x, 16g 200x, and 16h 400x.

Figs. 18a-h. Isoperla sordida nymph and ventral maxilla, Fall River, Deschutes County, OR. Submarginal setae groups A and B, Marginal setae C, Ventral surface setae D, Dorsal seta DS, Dorsal surface setae DSS, and Thin marginal seta TMS. White bars = 1 mm, 18e-f 100x, 18g 200x, and 18h 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.