Megaleuctra williamsae Hanson

Baumann, Richard W. & Stark, Bill P., 2013, The Genus Megaleuctra Neave (Plecoptera: Leuctridae) In North America, Illiesia 9 (6), pp. 65-93 : 85-89

Megaleuctra williamsae Hanson

( Figs. 73-84 )

Megaleuctra williamsae Hanson 1941:64 .

Holotype ♂ ( USNM). Type locality: Greenbriar Cove , Great Smoky Mountains , (Sevier Co.) Tennessee, examined Megaleuctra williamsae: Baumann, 1973:248 . Description of ♀

Material examined. NORTH CAROLINA: Graham Co., Robinsville, 9 June 1976 G.E. Bohart, 1 ♀ ( USUC). Haywood Co. , unknown locality, 16 June 1956, H.V. Weems, Jr., 1♂ ( CUIC). Tributary, Cove Creek , near Great Smoky Mountains National Park , 19 May 1994, R.W. Baumann, R.F. Kirchner, B.C. Kondratieff, 1♂, 1♀ ( BYUC). Jackson Co. , Mull Creek , Nantahala National Forest , 23 May 1993, B.C. Kondratieff, R.F. Kirchner, 1♂, 1♀ ( CSUC). Same site, 26 May 1993, B.P. Stark, 1♀ ( BPSC). Same site, 19 May 1994, R.W. Baumann, R.F. Kirchner, B.C. Kondratieff, 1♂, 1♀ ( CSUC). Macon Co. , Robin Branch, Wayah Bald, 11 March 1990, B.P. Stark, 4 larvae ( BPSC, ROMC). Same site, 21 May 1990, B.P. Stark, J. Parham, D. Tanner, 2♂ ( BPSC). Same site, 9 June 1998, B.P. Stark, 1♀ ( BPSC). Seep, Wayah Creek , Wayah Bald, 35° 09.523’N, 83° 33.916’W, 17 May 2011, B.P. Stark, 1♀ ( BPSC). Mitchell Co. , Tributary, Little Rock Creek , Hwy 261, E Roan Mountain , 38.10112N, 82.09245W, 14 May 2010, B.C. Kondratieff, R.E. Zuellig, D.R. Lenat, R.F. Kirchner, 1♂ ( CSUC). Swain Co. , Trickle to, Oconaluftee River , 26 April 1976, H.B.N. Hynes, 1 larva ( USNM). Yancey Co. , Tributary seep, Cane Creek , Mount Mitchell , 18 May 1994, R.W. Baumann, R.F. Kirchner, B.C. Kondratieff, 1♂ ( BYUC). Crabtree Meadows, 11 June, 1967, G.W. Byers, 1♂ ( SEMC); Tributary, Rock Creek , Hwy 80. S Hamrick, 35.7527N 82.20085W, 14 May 2010, B.C. Kondratieff, R.E. Zuellig, D.R. Lenat, R.F. Kirchner, 1♂ ( CSUC). SOUTH CAROLINA: Oconee Co. , Townes Creek , Bartram Trail, 26-27 May 1980, T.R White, J.S. Weaver, 1♀ ( BPSC). Pickens Co. , Sassafras Mountain , 18 May 1937, O.L. Cartwright, 1♀ ( CUCC). TENNESSEE: Sevier Co. , Greenbriar Cove, Great Smoky Mountains , 15 May 1938, I. W. Williams, 1♂, Holotype ( USNM). 10.2 mi. E Gatlinburg, Great Smoky Mountains National Park , 20 May 1970, O.S. Flint, Jr., 1♂, 1♀ ( USNM). Le Conte Trail , first stream, Great Smoky Mountains National Park , 25 May 1946, J.F. Hanson, 1♂, 2♀ ( USNM). Le Conte Lodge , Mount Le Conte , Great Smoky Mountains National Park , 9 August 1946, P. Hoff, 1♀ ( USNM). West Prong Little Pigeon River , Chimney Top Picnic Area , Great Smoky Mountains National Park , 29 April 1977, C.H. & E.S. Nelson, 1♂ ( CHNC). Ramsay Prong , Little Pigeon River , Great Smoky Mountains National Park , 20-21 May 1978, C.H. Nelson, 1♀ ( CHNC). West Prong Little Pigeon River , Hwy 441, Great Smoky Mountains National Park , 26 May 1984, R.W. Baumann, C.R. Nelson, 1♀ ( BYUC). VIRGINIA: Grayson Co. , Headwaters , Lewis Fork, Rt. 603, Lewis Fork Trail , Mount Rogers , 29 May 1982, B.C. Kondratieff, 1♂, 1♀ ( BYUC). Same site, 7 May 1983, B.C. Kondratieff, 2♀ ( VPIC). Same site, 12 May 1983, B.C. Kondratieff, 1 larva ( CSUC). Washington Co., Seeps along Whitetop Road, SW Elk Garden, 36.63939N 81.59625W, 1 June 2006, B.C. Kondratieff, R.F. Kirchner, R.E. Zuellig, 2♂, 4♀ ( CSUC).

Male. Macropterous. Length of forewing 14-15 mm; body length 11-13 mm. General color light brown. Wings hyaline, with dark stigma occupying more than half the costal space beyond the cord. Radial sector of forewing with two branches. Tergum 9 without large lobe-like processes ( Figs. 75 , 78); subgenital plate tongue-like, apex slightly emarginated ( Figs. 75 , 79); vesicle at base sternum 9 short, and narrow ( Fig. 75 ). Tergum10 without ventrobasal expansion ( Fig. 79 ). Epiproct short, forming a right angle at base in lateral aspect ( Figs. 75 , 78, 80, 82), broad at base, with middorsal groove and upturned hooks at apex ( Figs. 75 , 82). Subanal probe very long, cylindrical, directed upward and forward, usually fitting in middorsal groove of epiproct ( Figs. 74 , 77, 82), apex tapered, slightly truncate at tip ( Figs. 75 , 81, 82); cerci consist of a greatly elongate single segment ( Figs. 75 , 77, 78).

Female. Macropterous. Length of forewing 12-16 mm; body length 12-15 mm. Coloration similar to male. Head oval and somewhat flattened. Pronotum elongate, anterior corners squared off, posterior angles with large inward directed bevels ( Fig. 73 ). Radial sector of forewing with two branches. Sternum 8 formed to an ovipositor-like structure, with subgenital plate extending past tip of abdomen ( Figs. 76 , 83, 84), broadly rounded from beyond the base to almost the apex ( Figs. 76 , 83, 84); narrowing to short tip ( Fig. 84 ). Sternum 9 long and very thin ( Fig.84 ). Cerci inconspicuous ( Figs. 76 , 83).

Larva. Undescribed.

Egg. Undescribed.

Diagnosis. The male of this species is distinguished from M. flinti , the only other eastern North American species, by its differently shaped epiproct. In M. williamsae the epiproct is short and consists of a pair of angled processes, which form a groove that encloses the tip of the subanal probe ( Figs. 74 , 77, 78. 82), while in M. flinti it consists of a stout triangular structure that supports the midlength portion of the subanal probe when it is fully extended ( Figs. 22 , 25, 27 ) but forms a short wing-like structure when it is located at the base ( Figs. 26, 28, 30 ). Additionally, the subanal probe of M. williamsae lacks a median expansion ( Figs. 74, 75 , 77) whereas in M. flinti , it is expanded at midlength ( Figs. 22 , 25-28, 30 ). The subgenital plate of the female of M. williamsae is subequal in width from beyond the base to almost to the apex ( Figs. 83-84 ); whereas in M. flinti this structure narrows conspicuously from the base to the apex ( Figs. 31, 32 ). Additionally, the species are allopatric, with M. williamsae reaching its most northern range extension in southwestern Virginia, and M. flinti reaching its southernmost range extension in northern Virginia.

Figures

Fig. 73. Megaleuctra williamsae. 10 miles east of Gatlinburg, Tennessee, Great Smoky Mountains National Park. Female, head and pronotum.

Figs. 74-76. Megaleuctra williamsae. 10 miles east of Gatlinburg, Tennessee. Terminalia: 74. Male, dorsal. 75. Male, lateral. 76. Female, lateral.

Figs. 77-84. Megaleuctra williamsae. White Top Road, southwest of Elk Garden, Virginia. Male: 77. Genitalia, lateral, epiproct, terminal on subanal probe. 78. Genitalia, lateral, epiproct enclosing subanal probe at apex. 79. Subanal probe, base, dorsolateral. 80. Genitalia, dorsolateral, separated. 81. Subanal probe, apex, dorsal, close up. 82. Subanal probe and epiproct separated, dorsolateral. Female: 83. Genitalia, lateral. 84. Genitalia, terminal, lateral.

Figs. 21-24. Megaleuctra flinti, Hogcamp Brook, Shenandoah National Park, Virginia. Terminalia: 21. Male, dorsal. 22. Male, lateral. 23. Male, ventral. 24. Female, lateral.

Figs. 25-32. Megaleuctra flinti, Dogway Run, West Virginia. Male: 25. Genitalia, dorsal, epiproct, extended. 26. Genitalia, dorsal, epiproct, midlength. 27.Genitalia, lateral, epiproct, extended. 28.Genitalia, lateral, epiproct, midlength. 29. Epiproct, apical half, dorsal. 30. Genitalia, dorsolateral, epiproct, midlength. Female: Pheasant Hollow, West Virginia. 31. Genitalia, lateral. 32. Genitalia, ventral.