Sweltsa lyrata, Stark & Baumann, 2018

Stark, Bill P. & Baumann, Richard W., 2018, Two New Stonefly Species In The Sweltsa Coloradensis (Banks) Complex (Plecoptera: Chloroperlidae), Illiesia 14 (2), pp. 30-43 : 36-39

Sweltsa lyrata , sp. n.

( Figs. 16 , 18-29 , 38-39 , 43, 46 )

http://lsid.speciesfile.org/urn:lsid: Plecoptera .speciesfile.org: TaxonName:502536

Material examined. Holotype ♂, 3♂, 1♀ paratypes, Washington, Skagit Co., Friday Creek, Prairie Rd , 5 miles N of Burlington, 16 April 1967, K.E. Vander Mey (holotype, United States National Museum, paratypes BYU). Additional paratypes: CANADA: Alberta: Cameron Creek , Cameron Lake , Waterton Lakes National Park , 19 July1965, A. R. Gaufin , 26♂, 30♀ ( BYU). British Columbia: Duhamel Creek , Six Mile Rd , 30 May 2010, B. Stark, R. W. Baumann, 2♂, 1♀ ( BPSC). Yukon: Klondike River , Dempster Hwy , 23 June 1996, J.C. Abbott, K.W. Stewart, 8♂, 7♀ ( BPSC). Mayo River , Hwy 11, 63° 36’ N, - 135° 55’ W, 24 June 1996, K.W. Stewart, J.C. Abbott, 5♂, 3♀ ( BYU). McQuesten River , Hwy 2, 63°33’15.88” N, - 137°24’37.88” W, 24 June 1996, K.W. Stewart, J.C. Abbott, 3♂, 6♀ ( BYU). Ogilvie River , Dempster Hwy, 65°21’38.82” N, - 138°18’20.73” W, 21 June 1996, K.W. Stewart, J.C. Abbott, 17♂, 5♀ ( BYU). UNITED STATES: Idaho: Bonner Co. , Pack River , Pack River Rd, 26 May 2010, B. Stark, R. W. Baumann, 5♂, 8♀ ( BPSC). Montana: Gallatin Co. , Duck Creek , 8 miles N West Yellowstone, 9 June 1987, B.C. Kondratieff, 1♂, 2♀ ( CSUIC). Gallatin River , Squaw Creek Rd, 10 July 1999, B. Stark, L. Stark, 1♂, 1♀ ( BPSC). Mineral Co. , St. Regis River , Little Joe Rd, St. Regis , 25 May 2010, B. Stark, R. W. Baumann, 28♂, 8♀ ( BPSC). St. Regis River , Riverside, 11 June 1969, A. R. Gaufin, 4♂, 7♀ ( BYU). Trout Creek , Trout Creek Campground, 4 June 2010, B. Stark, R. W. Baumann, 23♂, 6♀ ( BPSC). Washington: Okanogan Co. , Buck Creek , 20 miles N of Winthrop, 9 June 1995, MacKenzie, 4♂, 1♀ ( BYU). Pend Oreille Co. Sullivan Creek , below Sullivan Lake , 2 June 2010, B. Stark, R. W. Baumann, 35♂, 43♀ ( BPSC). Whatcom Co. , Padden Creek , 33 rd Street, Bellingham, 27 April 1994, Graham, MacKenzie, 6♂, 1♀ ( BYU).

Adult habitus. Male forewing length 6.2-6.7 mm; female 7.0- 7.5 mm. Similar to S. coloradensis with hieroglyphic-like markings on head and pronotum ( Fig. 43 ). However considerable variation occurs in the pigmentation patterns of individuals within and between sites. Our impression is that the three species overlap in pigment pattern.

Male epiproct (n=14). Maximum width 310-410 μm, length 360-470 μm. Base conspicuously narrowed at stem and epiproct relatively wide across body at lateral projections giving a distinct stalked appearance ( Figs.18-29 ). Shoulders scarcely, or not at all projecting beyond base of hook ( Fig. 46 ).

Aedeagus (n=1). Length from base to base of apical finger-like lobes 466 μm, width across eye-like lobes to apices of lateral lobes 525 μm. Lateral lobes broad basally near outer margins of eye-like lobes; margins of lateral lobes strongly convergent, forming an overall football-shape to the aedeagal

body ( Fig. 16 ).

Female terminalia. Posterior margin of subgenital plate truncate, overlapping that of S. coloradensis in shape ( Figs. 38-39 ).

Larva. Unknown.

Etymology. The species name refers to the lyre- shaped dorsal aspect of the epiproct of this species. Diagnosis and distribution. Sweltsa lyrata is recognized by the prominent lateral projections, small apical projections and abruptly narrowed epiproct stem that give the epiproct a lyre-like shape. Males of this species are distinguished from those of S. mogollonica by the enlarged lateral lobes of the epiproct ( Figs.17-28 ), and from S. coloradensis by the prominent apical lobes of the epiproct in that species ( Figs.2-13 ). The aedeagus of this species (based on one specimen) is shorter than both additional species of the complex, and has the lateral lobes wider and more pointed at their apex. Populations exhibiting the S. lyrata epiproct type are known from the Northern Rocky Mountains including sites in Alberta, British Columbia and Yukon Territory and adjacent areas in Washington, Montana and Idaho.

Figures

Figs. 14-17. Sweltsa sp. aedeagus, ventral. 14. S. coloradensis, Nevada, White Pine Co., Berry Creek. 15. S. coloradensis, Colorado, Gilpin Co., South Boulder Creek. 16. S. lyrata, Yukon, Ogilvie River. 17. S. mogollonica, Arizona, Graham Co., Grant Creek. (al = apical lobe; ll = lateral lobe; vl = ventral lobe).

Figs. 18-23. Sweltsa lyrata male epiproct, dorsal. 18-19. Idaho, Bonner Co., Pack River. 20. Washington, Skagit Co., Friday Creek. 21. Washington, Whatcom Co., Padden Creek. 22-23. Alberta, Cameron Creek.

Figs. 24-29. Sweltsa lyrata male epiproct, dorsal. 24. Montana, Mineral Co., St. Regis River. 25. Montana, Gallatin Co., Duck Creek. 26. Montana. Mineral Co. Trout Creek. 27. Washington, Pend Oreille Co., Sullivan Creek. 28. British Columbia, Duhamel Creek. 29. Yukon, Klondike River.

Figs. 36-41. Sweltsa sp. female terminalia, ventral. 36-37. Sweltsa coloradensis, Colorado, Gilpin Co., South Boulder Creek. 38-39. Sweltsa lyrata, Montana, Mineral Co., St. Regis River. 40-41. Sweltsa mogollonica, Arizona, Apache Co., North Fork White River (SgP = subgenital plate).

Figs. 42-47. Sweltsa sp. head and pronotal pigment and epiproct variation. 42. Sweltsa coloradensis, Colorado, Eagle Co., Deep Creek. 43. Sweltsa lyrata, Montana, Mineral Co., St. Regis River. 44. Sweltsa mogollonica, New Mexico, Catron Co., Willow Creek. Pigment patterns shown here are variable within and between populations of the three species. 45. Sweltsa coloradensis epiproct, Colorado, Gilpin Co., South Boulder Creek. 46. Sweltsa lyrata epiproct, Washington, Pend Oreille Co., Sullivan Creek. 47. Sweltsa mogollonica epiproct, New Mexico, Catron Co., Willow Creek.

Figs. 2-7. Sweltsa coloradensis male epiproct, dorsal. 2-3. Colorado, Eagle Co., Deep Creek. 4-5. Colorado, Gilpin Co., South Boulder Creek. 6-7. Colorado, Gunnison Co., Quartz Creek.

Figs. 8-13. Sweltsa coloradensis male epiproct, dorsal. 8. Idaho, Bannock Co., Mill Creek. 9. Oregon, Umatilla Co., John Day River. 10. Utah, Wasatch Co., Cascade Springs. 11. Wyoming, Washakie Co., ESE Tensleep. 12. Nevada, Nye Co., South Fork Pine Creek. 13. South Dakota, Lawrence Co., Spearfish Creek.