Kathroperla siskiyou Stark & Kondratieff, 2015

Stark, Bill P., Kondratieff, Boris C. & Verdone, Chris J., 2015, Kathroperla Siskiyou, A New Stonefly Species From California And Oregon, U. S. A. (Plecoptera: Chloroperlidae), Illiesia 11 (8), pp. 92-103 : 96-99

Kathroperla siskiyou Stark & Kondratieff sp. n.

Wagner Gap Sallfly

( Figs. 9-19 )

Material examined. Holotype ♀, USA: OREGON, Jackson Co., Split Rock Creek , Wagner Gap Rd, 12 mi S Talent, 42.09480°N, 122.77397°W, 22 May 2014, B.C. Kondratieff, C.J. Verdone, J. Sandberg, B. Stark ( USNM). Paratypes, CALIFORNIA: Sierra Co., North Yuba River , Hwy 49, near Sierra City, 10 May 1983, R.W. Baumann, R.C. Mower, 1♀ ( BYUC). OREGON: Same data as holotype, 2♀ ( CSUC). Jackson Co., East Fork Ashland Creek , south of Ashland, 19 May 2000, R.W. Wisseman, 1♀ ( BYUC). Jackson Co., McDonald Creek , Wagner Gap Rd, 22 May 2014, B.C. Kondratieff, C.J. Verdone, 1♂ ( CSUC) .

Adult habitus. General color brown patterned with dark brown. Lateral margins of head bearing dark brown stripes extending from posterior margin to eye ( Fig. 15 ); occiput pale brown in fully pigmented specimens, but infuscated in some specimens with slightly darker brown pigment. Dark ocellar spot extends forward on frons to level of antennae; antennae dark brown. Pronotum with pale brown median stripe, broad sublateral dark stripes, and an almost complete marginal ring of dark pigment interrupted on lateral margins near midlength ( Fig. 15 ); sublateral stripes sometimes almost broken, or notched on lateral margins. Wings transparent, veins dark brown except pale brown C and Sc. Femora brown except apical black

18 19

ring; tibiae brown but slightly darker distally, proximally at knee and along inner margin. Abdomen pale brown on dorsum and bearing a darker median stripe and a pair of dark lateral stripes on terga 1-8; basal cercal segment pale brown but bearing minute dark spots around setal bases, subsequent segments black. Thoracic sterna dark brown; abdominal sterna brown with darker markings forming a broken, median longitudinal stripe from sterna 3-7.

Male. Forewing length 16 mm. Epiproct typical of genus but dorsolateral extensions diverge posterolaterally from central axis ( Fig. 16 ); anterodorsal margin of epiproct uniformly black. Basal cercal segments ca. 2-2.5 X long as wide. Vesicle body almost circular but with moderately wide base forming a short, stalk-like structure ( Fig. 17 ). Aedeagus broad and membranous except for a pair of curved, dark brown lateral bands and a ventromedian pale sclerite ( Fig. 18 ); surface of lateral bands bear fine, short, densely packed setae; distal margins foot-shaped. Aedeagal apex consists of three membranous lobes, median lobe finely divided by a suture-like line along most of its length.

Female. Forewing length 17-18 mm. Lateral margins of subgenital plate slightly concave beyond midlength, apex notched; apex extends over base of sternum 9 ( Fig. 19 ).

Egg. Outline oval. Length ca. 380-400 μm, equatorial width ca. 230-240 μm ( Figs. 9-10 ). Collar short, ca. 22-30 μm, wide ca. 70-80 μm ( Fig. 11 ), elaborately dissected, and surrounded by three irregular rows of meshes and a conspicuous outer ridge forming a ring ca. 104 μm in diameter ( Figs. 11-12 ). Anchor well developed, cushion shaped and covered with small globular bodies ( Fig. 10 ). Chorion bearing multiple rows of longitudinal striae composed of closely grouped, irregularly shaped tubercles ca. 2-3 μm wide; interstrial areas bear scattered tubercles similar to those which comprise striae ( Figs. 11, 13 ). Micropyles subequatorial in position and often associated with striae ( Fig. 14 ); orifices slightly larger in diameter than bead-like components of striae.

Larva. Unknown.

Etymology. The species name, used as a noun in apposition, is based on the type locality in the Siskiyou Mountains of southern Oregon. The proposed common name, Wagner Gap Sallfly, is based on the access road into the sites where most of the known specimens were collected. Common names for K. perdita (Longhead Sallfly) and K. takhoma (Slenderhead Sallfly) were previously proposed by Stark et al. (1998b; 2012).

Diagnosis. Although some overlap in subgenital plate shape occurs, females of K. siskiyou are usually distinguished from K. takhoma by a shorter subgenital plate, and by the egg structure which bears a collar and longitudinal striations formed from bead-like tubercles ( Figs. 11, 13 ). The new species and K. perdita completely overlap in subgenital plate structure and in head pattern, but the eggs differ in the form of the chorionic tubercles. In K. perdita these structures are thick and long ( Figs. 5-6 ), whereas in the new species they are formed as longitudinal clusters of beadlike structures ( Figs. 11, 13 ). The only known male specimen of this species appears intermediate between K. perdita and K. takhoma . The basal cercal segments and, general head coloration and pigment pattern of the dorsal margin of the epiproct are similar to those of K. perdita , whereas the vesicle shape and dorsal epiproct margin are more similar to K. takhoma . Males of the three Nearctic species have similar aedeagal structure but when a larger sample is available the shape and size of the lateral sclerites may offer another useful character. We offer a preliminary key below to assist in distinguishing these three species.

Figures

Figs. 9-14. Kathroperla siskiyou eggs, Split Rock Creek, Jackson Co., Oregon. 9. Entire egg, lateral aspect. 10. Entire egg with intact anchor. 11. Collar end chorionic detail. 12. Collar, apical aspect. 13. Anterior pole. 14. Chorionic detail (micropyle at arrow).

Figs. 15-19. Kathroperla siskiyou adult features. 15. Head and pronotum. 16. Male terminalia, dorsal. 17. Male sternum 9 with vesicle. 18. Male aedeagus, lateral (da = dorsoapical lobe; ls = lateral sclerite). 19. Female terminalia, ventral.

Figs. 1-6. Kathroperla perdita eggs. 1-4. Ross Creek, Lincoln Co., Montana. 5-6. Grande Ronde River, Union Co., Oregon. 1. Egg, lateral. 2. Chorionic detail (lt = linear tubercle; m = micropyle). 3. Collar end of egg (a = anchor). 4. Anterior pole (lid) of egg. 5. Collar end of egg (s = stria). 6. Anterior pole of egg.