Isoperla laucki Baumann & Lee, 2009

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 : 48

Isoperla laucki Baumann & Lee

( Figs. 7 a-d)

Isoperla laucki Baumann & Lee 2009 .

Holotype ♂, California, Humboldt County, Dragsaw Spring @ Rd 13N01.

Male. Aedeagus: sclerotized posterior process present; body with one posterior lobe, one large dorsal lobe, and a pair of small anterolateral lobes ( Fig. 7a ); one posterobasal patch of spinulae scattered below the sclerotized process and a long narrow posteroapical spinule patch concentrated above the sclerotized process ( Figs. 7 a-b); sclerotized process length <0.5 mm, digitate, apex a blunt point, and capable of complete ( Fig. 7a ) to partial eversion ( Fig. 7c ). 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. 7c ). Vesicle: pedunculate, length subequal to width, constricted near base with curved lateral margins, wider and rounded at apex ( Fig. 7d ).

Isoperla laucki is most similar to I. marmorata ( Table 1 ), with diagnostic differences in aedeagal spinule patch shape, location of sclerotized process, and sclerotized process shape. The spinules form an elliptical shaped patch distinctly separated from and placed above the insertion of the sclerotized process. The more rounded and in one case, bi-hemispherical shaped spinule patches of the I. marmorata complex are all placed above and adjacent to the insertion of the posterior sclerotized process. The I. laucki sclerotized process length is <0.5 mm, has parallel lateral margins, and a bluntly rounded apex. The sclerotized processes of the I. marmorata complex are longer (approaching 0.5 mm), and have expanded dorsal and ventral margins forming a blade-like apex with variable distal margins.

The above male description, including live everted aedeagal characters, agrees with the previous description of the aedeagus based upon scanning electron microscope preparation ( Baumann & Lee 2009, figs. 1-8). It was not noted in their methods if the live everted aedeagus was fixed in hot water. An unfixed aedeagus, after live eversion, will usually invert or deflate slightly, and might explain the slightly larger and expanded dorsal lobe in our study ( Fig. 7a ).

Additional Material Examined. CALIFORNIA, Humboldt Co., Unnamed tributary of Boise Creek , Hwy 299, 01/ V /2011, J.B. Sandberg, B.C. Kondratieff, 1♀ ( JBSC) .

Figures

Figs. 7-8. Adult male characters of Isoperla laucki, Dragsaw Spring, Humboldt Co., CA, and I. marmorata, Big Chico Cr., Tehama Co., CA, 32-40x. Fig. 7a. I. laucki aedeagus, lateral; sclerotized process (white arrow & inset-lateral view); posteroapical and posterobasal spinule patches (black arrows). Lobes A: posterior, B: dorsal, C: anterolateral pair. Fig.7b. Aedeagus, ventral; sclerotized process (white arrow & inset-dorsal view); posterobasal spinule patch (black arrow). Fig. 7c. Paraprocts (left white arrow); sclerotized process (right white arrow); posteroapical spinule patch (black arrow). Fig. 7d. Vesicle. Fig. 8a. I. marmorata aedeagus, lateral; sclerotized process (white arrow & inset-lateral view); paraprocts (black arrow). Lobes A: posterior, B: dorsal, C: anterior. Fig. 8b. Aedeagus, posterior; spinule patch & sclerotized process (black arrow). Fig. 8c. Paraprocts (arrow). Fig. 8d. Vesicle.