Isoperla sordida Banks, 1906

Sandberg, John B. & Kondratieff, Boris C., 2013, The Isoperla Of California (Plecoptera: Perlodidae); Updated Male Descriptions And Adult Keys For 18 Western Nearctic Species, Illiesia 9 (5), pp. 34-64 : 57

Isoperla sordida Banks

( Figs. 16 a-d)

Isoperla sordida Banks 1906 .

Holotype ♂, California, Los Angeles.

Male. Aedeagus: sclerotized posterior process present; body of aedeagus with two posterior lobes, one dorsal lobe, and one anterior lobe ( Fig. 16 a ); sclerotized process length approaching 0.5 mm, partially recurved and rod-like, apex expanded, flattened and projecting dorsally in lateral view ( Figs. 16a ), bifurcate subapically with two ventrally directed rounded lobes in posterior view ( Fig. 16b inset), width of lobes 0.18-0.20 mm. Abdominal terga 8-9, 9, 9-10: without stout spinulae or long stout setae. Posterolateral margins of at least abdominal segment 8 with scale-like setae clustered in brushes of several setae. Paraprocts: curved dorsally, length if straightened subequal to combined first and second cercal segments, tapering gradually to long blunt apices ( Fig. 16c ). Vesicle: rounded lobe, widest at base with broadly rounded apical margin ( Fig. 16d ).

Isoperla sordida has been recently collected in two high elevation (above 1524 m), spring fed or snow melt eastern Sierra Nevada streams ( Sandberg 2011b); and shares similar characters with other species from the I. sordida complex and I. umpqua ( Table 1 ). It is most similar to I. denningi . See comments under I. denningi .

Figures

Figs. 15-16. Adult male characters of Isoperla sobria, Tyee Spring, Skamania Co., WA and I. sordida, Cold Water Cr., Mono Co., CA, 25-40x. Fig. 15a. I. sobria aedeagus, lateral (Tyee Sp., in copula); spinule patch (arrow). Lobes A: anterior, B: dorsal pair, C: posteroapical (aberrant). Fig. 15b. Aedeagus, posterior; spinule patch (arrow). Fig. 15c. Paraprocts (black arrow), Lk. Davis-Corral Sp.; spinulae patch, lateral (white arrow); dorsal pair of lobes in typical position. Fig. 15d. Vesicle. Fig. 16a. I. sordida aedeagus, lateral; sclerotized process (white arrow); paraproct (black arrow). Lobes A: posteroventral, B: posteromedian, C: dorsal, D: anterior. Fig. 16b. Aedeagus ventral; sclerotized process (arrow & inset-posterior view).Fig. 16c. Paraprocts (black arrow); sclerotized process (white arrow). Fig. 16d. Vesicle.