Isoperla miwok Bottorff & Szczytko, 1990

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 : 49-51

Isoperla miwok Bottorff & Szczytko

( Figs. 9 a-d, 20 d)

Isoperla miwok Bottorff & Szczytko 1990 .

Holotype ♂, California, El Dorado County, Indian Creek, 3.3 km NE Michigan Bar Bridge .

Male. Aedeagus: sclerotized posterior process absent; body with one small posterior lobe, one large dorsal lobe and a pair of small pointed lobes on apicolateral margins ( Fig. 9 a-b); a pair of long curved patches of spinulae on posteroventral surface ( Fig. 9b ), and a broad patch of spinules on the posteroapical surface ( Figs. 9 a-c). 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 abruptly to blunt apices ( Fig. 9c ). Vesicle: lobe barely perceptible, vestigial when present, widest at base with broadly rounded apex ( Fig. 9d ).

Isoperla miwok is most similar to the other species included in the I. sobria complex based on the absence of an aedeagal posterior sclerotized process, and presence of stout spinules arranged in variable patches ( Table 1 ). It is distinctive among the western Nearctic species in possessing a double band of stout spinulae on the aedeagal posterobasal margin.

The current study aedeagal description conforms to the previous description. However, the live everted and fixed aedeagus lacks the single extended tube-like lobe on the anteroapical margin ( Bottorff et al. 1990, fig. 4). The anterior margin in this study possesses at least one anteromedian pair of inverted membrane areas (openings) which differs from the original description. A second smaller and more apical pair is also present. Clearing the everted and fixed aedeagus in KOH allowed observation of the anteroapical and anteromedian inverted processes inside the aedeagal body ( Fig. 20d , dorsal aspect providing the best view).

Figures

Figs. 9-10. Adult male characters of Isoperla miwok, Campbell Cr., Butte Co., CA and I. mormona, Big Chico Cr., Butte Co., CA, 40-50x. Fig. 9a. I. miwok aedeagus, lateral; posteroventral pair and posteroapical spinule patches (arrows). Lobes A: posterior, B: dorsal. Fig. 9b. Aedeagus, ventral; posteroventral pair of spinule patches (black arrow), small pointed apicolateral lobe (white arrow). Fig. 9c. Paraprocts (white arrow); posteroapical spinule patch (black arrow). Fig. 9d. Vesicle. Fig. 10a. I. mormona aedeagus, lateral; paraproct (black arrow); fine dorsoapical spinulae (white arrow). Lobe Adorsoanterior. Fig. 10b. Aedeagus, ventral; paraproct base (arrow). Fig. 10c. Paraprocts (black arrow); fine dorsoapical spinulae (left white arrow); abdominal spinulae (right white arrow). Fig. 10d. Vesicle.

Figs. 20a-f. The cleared aedeagus of six western Nearctic Isoperla species after live evertion; membranous opening of internal tube like process or apex (white arrows); tube like internal process (black arrows). 50x (20b, d & e, cropped and enlarged). 20a. I. baumanni, lateral view, partially everted; 20b. I. fulva, lateral view; 20c. I. marmorata, lateral view; 20d. I. miwok, dorsoapical view, tube like process openings along anteroapical margin; 20e. I. roguensis, ventral view, tube like process openings along anteroapical margin; 20f. I. tilasqua, lateral view.