Isoperla fulva Claassen, 1937

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 : 46-48

Isoperla fulva Claassen

( Figs. 6 a-d, 20 b)

Isoperla fulva Claassen 1937 .

Holotype ♂, Utah, Logan River.

Male. Aedeagus: sclerotized posterior process present; body with one posterior lobe, one small dorsal lobe, and one large anterior lobe ( Fig. 6a ); one small bulbous patch of spinulae above sclerotized process ( Figs. 6 a-c); sclerotized process length approaching 0.5 mm when fully extended, blade-like in lateral view ( Fig. 6a ), distal margin expanded and slightly membranous in posterior view ( Fig. 6b ), and narrow proximal portion of sclerotized process sometimes extended past posterior aedeagal membrane ( Fig. 6a ). 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. 6a ). Vesicle: rounded lobe, widest at base with broadly rounded apical margin ( Fig. 6d ).

Isoperla fulva is most similar to the two other I. marmorata complex species, I. marmorata and I. roguensis . These species differ in paraproct shape and aedeagal characters. The paraprocts taper abruptly to blunt apices in I. fulva , taper gradually to blunt apices in I. marmorata , and taper abruptly to tiny sharp apices in I. roguensis ( Table 1 ). The distal margin of blade-like sclerotized processes is thin in I. marmorata , expanded in I. fulva and expanded and variably-shaped in I. roguensis .

The aedeagus of this species was described with an additional pair of long narrow tubular lobes extending from the base of the anterodorsal lobe ( Szczytko & Stewart 1979, fig. 138C). When using the live eversion method, these processes remain inverted ( Fig. 6a ); however two small areas in inverted membrane are present on anterior lobe C of this study (not discernible in Fig. 6a ). The live everted aedeagus was cleared in KOH, which allowed observation of an inverted pair of tube-like processes within the aedeagus, and openings along the anteroapical margin ( Fig. 20b ). The small dorsal lobe B ( Figs. 6a & c ) in the current study possesses a pair of minute, closely placed holes from which seminal fluid streamed after live eversion and fixing. These dorsal aedeagal openings require further study before their function can be determined.

Isoperla fulva is putatively known from California based on three males and one female (El Dorado and Modoc counties - Jewett 1960) and Plumas County ( Szczytko & Stewart 1979) collected in the 1940’s and 1950’s. No recent material (everted males) from California compares well with the Colorado and Utah specimens examined for this study, and the California I. fulva records were determined before the description of I. roguensis . The El Dorado County male was likely collected from Weber Creek, south of Camino, 10 miles (16 km) north of Placerville, where Sandberg (2011b) collected I. marmorata and I. mormona .

Additional Material Examined. COLORADO, Larimer Co., Sand Creek , Ruby Wash, Red Mountain Open Space, 24/ V /2012, B.C. Kondratieff & D. Givens, 5♂, 2♀ ( CSUC); 17/ VI /2012, B.C. Kondratieff & R. Stokes, 10♂, 3♀ ( CSUC) . OREGON, Harney Co., Trout Creek , Whitehorse Ranch Rd 18 mi (29 km) SE Fields, 42.17439°N, 118.43199°W, 20-21/ V /2013, J.B. Sandberg, B.C. Kondratieff, 2♂, 1♀ ( JBSC); Union Co., Grande Ronde River, Hwy 244, Hilgard Junction State Park ( Hwy 84), 45.34323°N, 118.24013°W, 22/ V /2013, J.B. Sandberg, B.C. Kondratieff, 2♂, 3♀ ( JBSC) . UTAH, Juab Co., Pole Creek, FR 016 below confluence Pole Canyon, 14/ VI /2012, B.C. Kondratieff & R. W. Baumann, 10♂, 23♀ ( CSUC); Salt Creek, Ponderosa Campground , 14/ VI /2012, B.C. Kondratieff & R . W. Baumann, 2♂, 2♀ ( CSUC) ; Utah Co., Nebo Creek, FR405, 13/ VI /2012, B.C. Kondratieff & R.W. Baumann, 1♂, 8♀ ( CSUC) .

Figures

Figs. 5-6. Adult male characters of Isoperla denningi, San Mateo Cr., San Diego Co., CA, and I. fulva, Sand Cr., Larimer Co., CO & Pole Cr., Juab Co., UT, 32-50x. Fig. 5a. I. denningi aedeagus, lateral; sclerotized process (arrow & inset-lateral view). Lobes A-B: posterobasal, C: posteroapical, D: dorsolateral pair. Fig. 5b. Aedeagus, ventral; sclerotized process (arrow & inset-posterior view). Fig. 5c. Paraprocts (arrow). Fig. 5d. Vesicle. Fig. 6a. I.fulva aedeagus, lateral; sclerotized process (left white arrow & inset-lateral view); spinule patch (right white arrow & inset); paraprocts (inset-black arrow). Lobes A: posterior, B: dorsal, C: anterior. Fig. 6b. Aedeagus, ventral; sclerotized process (arrow & inset-posterior view). Fig. 6c. Aedeagus, dorsal; sclerotized process (black arrow); spinule patch (white arrow). Fig. 6d. 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.