Isoperla umpqua Szczytko & Stewart, 2013

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 : 57-59

Isoperla umpqua Szczytko & Stewart

( Figs. 18 a-d)

Isoperla muir Szczytko & Stewart 2004 . Nomen nudum.

Isoperla umpqua Szczytko & Stewart 2013 . Holotype ♂, Oregon, Douglas County, Muir Creek, Hwy 230, downstream from bridge .

Male. Aedeagus: sclerotized posterior process present; body with one large dorsoanterior lobe ( Fig. 18a ); sclerotized process length approximately 0.5 mm, recurved and rod-like, with parallel lateral margins, apex clavate, and distal margin rounded in lateral and posterior views ( Figs. 18 a-c). Mesoposterior area of eighth and ninth terga with bipartite patches of short stout spinulae and long fine scattered setae ( Fig. 18c ). 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. 18c ). Vesicle: pedunculate, length subequal to width, constricted near base with curved lateral margins, wider and rounded at apex ( Fig. 18d ).

Based upon the presence of a sclerotized posterior process, absence of distinct aedeagal spinule patches, and pedunculate vesicle shape, I. umpqua is placed within the I. sordida complex ( Table 1 ). It differs from all other I. sordida complex species by possessing short stout spinulae arranged in bipartite patches along mesoposterior margins of terga 8-9. The clavate sclerotized posterior process is most similar to I. adunca ; however its length is approximately twice as long as I. umpqua . Isoperla umpqua is known only from Oregon, and similar to I. baumanni , is from a single location.

Figures

Figs. 17-18. Adult male characters of Isoperla tilasqua, Meacham Cr., Umatilla Co., OR and I. umpqua, Muir Cr., Douglas Co., OR, 25-40x. Fig. 17a. I. tilasqua aedeagus, lateral; large basal spinule patch & thin apical patch (arrows). Lobes A-B: posterior. Fig. 17b. Aedeagus, posterior; large basal spinule patch (arrow). Fig. 17c. Paraprocts (white arrow); apical thin spinule patch (right arrow); large basal patch (left arrow). Fig. 17d. Vesicle. Fig. 18a. I. umpqua aedeagus, lateral; sclerotized process (arrow). Lobe A: dorsoanterior. Fig. 18b. Aedeagus, ventral; sclerotized process (arrow & insetposterior view). Fig. 18c. Paraproct (left white arrow); sclerotized process (right white arrow); abdominal tergite 9 spinulae (black arrow). Fig. 18d. Vesicle.