Megaleuctra stigmata (Banks)

Baumann, Richard W. & Stark, Bill P., 2013, The Genus Megaleuctra Neave (Plecoptera: Leuctridae) In North America, Illiesia 9 (6), pp. 65-93 : 81-85

Megaleuctra stigmata (Banks)

( Figs. 1 , 54-72 )

Nemoura stigmata Banks 1900:244 .

Holotype ♂ ( MCZC). Type locality: Winnipeg, British America , (British Columbia or Manitoba), examined, slide of wings and leg

Megaleuctra spectabilis Neave 1934:4 .

Holotype female ( CNIC). Type locality: Campbell Creek , Purcell Range , British Columbia, examined, synonymy Claassen 1937:47

Megaleuctra sierra Fields 1977:211 .

Holotype female ( CASC). Type locality: Shirttail Creek, Tahoe National Forest , (Placer County), California, examined, new synonymy

Material examined. CANADA: Province Uncertain: Winnipeg, J.B. Smith , 17 June, unknown year, 1♂, M. stigmata Holotype ( MCZC) . ALBERTA: Lower Caribou Lake, Jasper National Park , 20 June 1979, D.B. Donald, 1♀ ( DBDC) . Lineham Brook, 7200’ Waterton Lakes National Park , 9 July 1975, D.B. Donald, 1♀ ( DBDC) . High River , l June 1927, O. Bryant, 1♀ ( CUIC) . BRITISH COLUMBIA: Campbell Creek, Purcell Mountains , 29 May 1933, R. Neave, 2♀, includes M. spectabilis Holotype ( CNCI) . Same site, 11 June 1933, R. Neave, 1♀ ( CNCI) . Seeps, Duhamel Creek, above West Arm Kootenay Lake , 49° 38’ N 117° 16’ W, 27- 30 May 2010, R.W. Baumann, B.P. Stark, 1♂, 4♀ ( BYUC, BPSC) . Tributary, Fry Creek, Purcell Mountains , 18 June 1933, R. Neave, 1♀ ( CNCI) . Seep, South Fork Gray Creek, Oliver Lake Road, Purcell Mountains , 49°37’ N 116°42’ W, 1 June 2010, R.W. Baumann, B.P. Stark, 1♂, 1♀ ( BYUC) . UNITED STATES: CALIFORNIA: El Dorado Co., Tributary, North Cosumnes River , E Grizzly Flats , near Meiss Ranch, R.L. Bottorff , 6 June 1986, 1♀ ( RLBC) . Bendorf Spring, near Grizzly Flat, R.L. Bottorff , 4 December 1986, 2 larvae ( RLBC) . Same site, 9-26 March 1987, R.L. Bottorff, 1♂ ( RLBC) . Same site, 14-27 April 1987, R.L. Bottorff, 10♂, 4♀ ( BYUC, CSUC, RLBC) . Same site, 4 May 1987, R.L. Bottorff, 3♂, 7♀ ( BYUC, CSUC, RLBC, USNM) . Same site, 16 May 1998, B.P. Stark, C.R. Nelson, R.L. Bottorff, S.W. Szczytko, I. Sivec, 1♀ ( BYUC) . 1 mi. E Pacific House, Hwy 50, near El Dorado Canal, W.D. Shepard, C. Barr , 4 April 1992, 2♂, 3♀ ( CASC) . Same site, 28 April 1992, F. Andrews, T. Eichlin, 1♂, 1♀ ( BYUC) . Placer Co., Shirttail Creek, Tahoe National Forest , W.C. Fields, Jr. , 9 June 1974, 1♀, M. sierra Holotype ( CASC) . Sierra Co., Mossy falls, Hwy 49, near Indian Creek , 18 May 1983, R.W. Baumann, R.C. Mower, M.F. Whiting, 1♂ ( BYUC) . Seep along unnamed stream, Hwy 49, mile marker 1.02, 39.49845° N 121.01535° W, 21 March 2010, A.B. Richards , 1♂ ( ABRC) . IDAHO: Idaho Co., Low Creek, New Elk Summit Road , Powell District , 27 May 1972, R.A. Haick, L. Lockwood, D.S. Potter, 1♂, 5♀ ( BYUC, USNM) . Seep, below ’ Isoperla’ Springs, Powell District , 27 May 1972, R.A. Haick, 1♂ ( BYUC) . Seep, Savage Pass , 27 May 1972, R.A. Haick, 3 larvae ( BYUC) . Winis Spring, Grave Peak, Selway Bitteroot Wilderness Area , 11 Sept. 1971, D.S. Potter, R.A. Haick, 2 larvae ( BYUC) . Latah Co., Moscow Mountain , 25 April 1953, W.F. Barr, 1 larva ( UIIC) . MONTANA: Flathead Co., Bear Creek, Hwy 2, Morias Pass , 17 July 1969, R.A. Haick, 1♀ ( BYUC) ; Bear Creek, E Echo Lake , 24 April 2006, B. Reid, 1♀ ( UMBS) . Spring, south end of Johns Lake , 10 August 1966, G.W. Swenson, 1 larva ( BYUC) ; Mac Donald Creek, Marve Cascade, Glacier National Park , 13 May 1993, J. Giersch, 1 ♀ ( UMBS) . Seep, Red Meadow Lake Road , 13 July 1972, R.A. Haick, L.A. Fisher, 1 larva ( BYUC) . Glacier Co., Grinnell Glacier Trail, Glacier National Park , 5 August 1972, D.S. Potter, R.A. Haick, 1 larva ( BYUC) . Lake Co., Boulder Creek, Flathead Lake , 8 May 1971, D.S. Potter, 2♀ ( BYUC) . Crane Creek, Hwy 35, east shore, Flathead Lake , 25 April 1970, D.S. Potter, R.A. Haick, 1♂, 2♀ ( BYUC) . Same site, 3 May 1970, D.S. Potter, 1♀ ( BYUC) . Same site, 15 May 1970, R.L. Newell, 1♂ ( BYUC) . Same site, 10 April 1973, R.A. Haick, C. Daugherty, 1 larva ( BYUC) . Spring, Hundred Road, Flathead Indian Reservation , near Saint Ignatius , 7 April 2007, R. Durfee, 1♀ ( CSUC) . Spring , Thorne Creek , Hundred Road, Flathead Indian Reservation, 20 April 2007, R. Durfee, 1 ♀ ( CSUC) . Talking Water Creek , Hwy 35, Flathead Lake, 15 April 2003, R.L. Newell, 1♂, 2♀ ( BYUC) . Same site, 19 April 2003, R. L. Newell, 1♂, 2♀ ( UMBS) . Same site, 9 May 2005, R.L. Newell, 1 ♀ ( UMBS) . Rotten log in groundwater seep, Yellow Bay State Recreation Area, Flathead Lake, 28 June 1987, unknown collector, 5 larvae ( UMBS) . Missoula Co., Seep , Butler Creek , Snow Bowl Ski Area, 4 May 1972, R.A. Haick, 2♂, 7♀, 6 larvae ( BYUC, CSUC) . Same site, 10 May 1972, R.A. Haick, 6♂, 1♀ ( BYUC, CSUC) . Same site, 26 May 1972, D.S. Potter, 1♂ ( BYUC) . Same site, 25 August 1972, R.A. Haick, 12 larvae ( BYUC) . Same site, 19 May 1973, R.A. Haick, 3♂, 6♀ ( BYUC) . Same site, 17-18 August 1973, G.B. Wiggins, 1 larva ( ROMC) . Seep , Glacier Lake Trail, Mission Mountains Wild Area, 24 June 1971, D.S. Potter, R.H. Haick, 18 exuviae ( BYUC) ; Seep , Grant Creek, E Missoula, 11 April 1972, R.A. Haick, 4 larvae ( BYUC) . Same site, 23 May 1972, R.A. Haick, 2♀ ( BYUC) . Powell Co., Keno Creek Spring, Lubrecht Experimental Forest, R.A. Haick, l July 1971, 12 exuviae ( BYUC) . Ravalli Co., Left tributary, Middle Fork Bear Creek , 6180‘, Bitterroot Valley, 1 July 1996, A.L. Sheldon, 1♂ ( BYUC) . Headwater spring, FR 5623, 1 mi N Como Lake, Bitterroot National Forest, 24 April 2007, R.L. Durfee, 1♂ ( CSUC) . Same site, 2 May 2008, R.L. Durfee, 1♂, 2♀ ( CSUC) . Tributary , Gash Creek, 6200’, Bitterroot Valley, 21 June 1995, A.L. Sheldon, 1♂ ( BYUC) .

Male. Macropterous. Length of forewing 14-15 mm; body length 12-13 mm. General color brown. Wings hyaline, with dark stigma in costal space occupying more than half the costal space beyond the cord. Radial sector of forewing with 2-5 branches. Tergum 9 with a pair of large narrowly separated lobes, apically blunt, slanted posteriorly; darkly sclerotized forked structure at base, with long setae ( Figs. 54, 55 , 61); subgenital plate tongue-like, apex rounded, sometimes upturned ( Figs. 55 , 70); vesicle at base of sternum 9 long, and narrow. Tergum 10 with ventrobasal expansion darkly sclerotized, elongate, tip emarginate ( Figs. 55 , 61); epiproct broad at base dorsally, with large middorsal groove ( Figs. 57 , 65 ), forming rounded fork at apex, bearing small rounded processes laterally, ornamented with narrow leaf-like lobes, when expanded ( Figs. 58, 62 ); epiproct stout and broad, rectangular dorsally, with large, paired, downward forked apical processes when in midlength position (Figs, 65, 67), when expanded, broader at base, terminating in narrow apex, which surrounds apex of subanal probe ( Figs. 54, 55 , 57, 61). Subanal probe directed upward, fitting in middorsal groove of epiproct ( Figs. 54 , 57, 61, 62), tip expanded, with subapical notch in lateral view ( Figs. 64 , 68 ), upper lobe small, arched dorsally, with a pointed tube bearing apex, lower lobe large and broadly rounded ( Figs. 60, 64 , 66, 68 ). Cerci single segmented, elongate ( Figs. 54, 55 , 59, 70).

Female. Macropterous. Length of forewing 16-18 mm; body length 19-20 mm. Coloration similar to male. Radial sector of forewing with 2-5 branches, crossveins in intercubital space 15-20. Sternum 8 with subgenital plate extending past tip of abdomen 1.5-2.0 mm, narrowing gradually to tip, round in cross section ( Fig. 56 ). Sternum 9 forming a long, narrow ovipositor ( Figs. 71, 72 ).

Larva. Undescribed.

Egg. Undescribed.

Diagnosis. The epiproct of M. stigmata males is more similar to that of M. complicata than to M. kincaidi , the other western species. In M. complicata this structure bears prominent, ventrally directed apical hooks ( Figs. 3 , 5, 8, 9 ) which gives the lateral aspect of the structure a meat hook-like appearance not found in M. kincaidi ( Figs. 36 , 40), whereas in M. stigmata the ventrally directed hooks are thinner and pointed downward at a sharper angle ( Figs. 55 , 61-63, 67). Males of M. stigmata have a pair of stout dorsal lobes on tergum 9, which are broadly rounded and slant posteriorly ( Figs. 54, 55 , 61, 65, 67, 69), whereas in M. complicata ( Figs. 2, 3 , 13, 15 ) and M. kincaidi ( Figs. 36 , 38, 42, 48, 51), the paired lobes are thinner and terminate in pointed tips.

Remarks. The exact type locality of M. stigmata is unknown, but Frison (1942) indicated the probability “…that the type was collected at or near Winnipeg, Manitoba ”, however, Burton (1984) indicated “…its occurrence in Manitoba is questionable.” Ricker and Scudder (1975) listed the Purcell Mountains, British Columbia Megaleuctra records by Neave (1934), as M. spectabilis , but Baumann & Stark (2010) recently collected males and females, indistinguishable from those of M. stigmata , from near the type locality of M. spectabilis , consequently we treat M. spectabilis as a junior synonym in agreement with Claassen (1937). Megaleuctra sierra Fields (1977) has been recognized as a different species since its description. However, comparison of the holotype and males collected from nearby localities in the Sierra Nevada Mountains, with specimens of M. stigmata from the northern Rocky Mountains, indicates that M. sierra is also a synonym of M. stigmata .

Figures

Fig. 1. Megaleuctra stigmata, Talking Water Creek, Montana. Male, Live, habitus, dorsal, macropterous. (Photo courtesy of R.L. Newell).

Figs. 54-56. Megaleuctra stigmata. Butler Creek, Montana. Terminalia: 54. Male, dorsal. 55. Male, lateral. 56. Female, lateral.

Figs. 57-64. Megaleuctra stigmata. Bendorf Spring, California. Male: 57. Genitalia, dorsal, epiproct, extended. 58. Epiproct, apex, dorsal. 59. Genitalia, dorsal, base. 60. Subanal probe, apex, anterior. 61. Genitalia, lateral, epiproct, extended. 62. Epiproct, expanded, enclosing subanal probe. 63. Subanal probe and epiproct, lateral, separated. 64. Subanal probe, apex, lateral.

Figs. 65-72. Megaleuctra stigmata. Gray Creek, British Columbia. Male: 65. Genitalia, dorsal, epiproct, midlength. 66. Subanal probe, apex, dorsal. 67. Genitalia, lateral, epiproct, midlength. 68. Subanal probe, apex, lateral. 69. Genitalia, anterior. 70. Genitalia, ventral. Female: Bendorf Spring, California. 71. Genitalia, lateral. 72. Genitalia, ventrolateral.

Figs. 2-4. Megaleuctra complicata, Still Creek, Oregon. Terminalia: 2. Male, dorsal. 3. Male, lateral. 4. Female, lateral.

Figs. 5-12. Megaleuctra complicata, Willis Creek, Oregon. Male: 5. Genitalia, lateral, open. 6. Genitalia, dorsal, open. 7. Genitalia, lateral, epiproct, extended. 8. Genitalia, apex, lateral, closed. 9. Subanal probe, apex, ventral. 10. Subanal probe, apex, lateral. 11. Vesicle, ventral. Female, 12. Genitalia, ventral.

Figs. 35-37. Megaleuctra kincaidi, Lolo Pass, Idaho. Terminalia: 35. Male, dorsal. 36. Male, lateral. 37. Female, lateral.

Figs. 13-20. Megaleuctra complicata, Still Creek, Oregon. Male: 13. Genitalia, dorsal, epiproct, midlength. 14. Subanal probe, apex, dorsal. 15. Genitalia, lateral, epiproct, midlength. 16. Subanal probe, apex, lateral. 17. Genitalia, anterior, epiproct, midlength. 18. Genitalia, ventral. Female: 19. Genitalia, ventral. 20. Genitalia, lateral.