Isoperla denningi Jewett 1955
Creators: name: Sandberg, John B.
name: Kondratieff, Boris C.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Plecoptera
Perlodidae
Isoperla
Isoperla denningi

description: <i>Isoperla denningi</i> Jewett (Figs. 5 a-d) <i>Isoperla denningi</i> Jewett 1955. Holotype &amp;male;, California, Los Angeles County, 4 mi W Tanbark Flat. <b>Male</b>. Aedeagus: sclerotized posterior process present; body with two posterobasal lobes, one large posteroapical lobe, and one dorsolateral pair of rounded lobes (Fig. 5a); sclerotized process length &lt;0.5 mm, recurved and rod-like, apex clavate in lateral view (Fig. 5a), bifurcate in posterior view, lateral apices short and rounded (Fig. 5b), and width of expanded apicolateral lobes 0.09-0.10 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 blunt apices (Fig. 5c). Vesicle: pedunculate, length subequal to width, constricted near base with curved lateral margins, wider and rounded at apex (Fig. 5d). <i>Isoperla denningi</i> is common in southwestern California, from Santa Barbara County south to San Diego County and occasionally coexists with <i>I</i>. <i>acula</i>, <i>I. adunca</i> and <i>I. mormona</i> (Sandberg 2011b). It is most similar to the species in the <i>I. sordida</i> complex, specifically <i>I. sordida</i> Banks 1906 (Table 1), with discernible differences in aedeagal characters. Both species have four aedeagal lobes in lateral view, however <i>I. denningi</i> has a pair of dorsal lobes and <i>I. sordida</i> has only one. The sclerotized processes are somewhat similar; both are slightly bifurcate with short rounded apices. The difference is the plane in which these apices lie: for <i>I. sordida</i>, the apical plane is perpendicular to the body of the process, and for <i>I. denningi</i>, the apical plane is parallel with the sclerotized process body. Additionally, the widths of the bifurcate apices differ: 0.09-1.0 mm for <i>I. denningi</i> and 0.18-0.20 mm for <i>I. sordida</i>. <b>Additional Material Examined.</b> CALIFORNIA, Riverside Co., San Juan Creek, 0.4 mi (0.6 km) N Lion Canyon Creek, 19/ V /2011, larvae (ABLC); San Diego Co., Devils Canyon Creek, above San Mateo Canyon Creek, 16/ V /2011, larvae (ABLC); King Creek, 1.1 mi (1.77 km) below Grove Drive, 30/ V /2012, larvae (ABLC); Santa Ysebel Creek, 2 mi (3.2 km) S Dan Price Creek, 29/ V /2011, larvae (ABLC); Juaquapin Creek, above Sweetwater River, 01/ VI /2011, larvae (ABLC).
description: Published as part of <i>Sandberg, John B. &amp; Kondratieff, Boris C., 2013, The Isoperla Of California (Plecoptera: Perlodidae); Updated Male Descriptions And Adult Keys For 18 Western Nearctic Species, pp. 34-64 in Illiesia 9 (5)</i> on page 46, DOI: 10.5281/zenodo.4760870
description: {"references": ["Jewett, S. G., Jr. 1955. Notes and descriptions concerning western North American stoneflies (Plecoptera). The Wasmann Journal of Biology, 13: 145 - 155.", "Sandberg, J. B. 2011 b. The Isoperla of California (Plecoptera: Perlodidae); larval descriptions and a key to 17 western Nearctic species. Illiesia, 7: 202 - 258.", "Banks, N. 1906. New species of Perlidae. The Canadian Entomologist, 38: 335 - 338."]}