Isoperla OF
Creators: name: Sandberg, John B.
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Plecoptera
Perlodidae
Isoperla

description: 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
description: Published as part of 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) on pages 209-210, DOI: 10.5281/zenodo.4760320