Leuctra colemanorum, Harrison & Stark, 2010

Harrison, Audrey B. & Stark, Bill P., 2010, Two New Species Of Stoneflies In The Leuctra Ferruginea Group (Plecoptera: Leuctridae), With Notes On The Leuctra Species Known For Mississippi And Alabama, U. S. A., Illiesia 6 (3), pp. 16-33 : 17-23

Leuctra colemanorum sp.n.

( Figs. 1-14 , 41-44 )

Material examined. Holotype ♂ and 16♂, 15♀ paratypes, Mississippi, Yalobusha Co., Denly Spring #2, Air Mount Road West , 33.96972° N, 89.56572° W, 24 October 2009, A. Harrison (holotype INHS, paratypes BPS, AH). Additional paratypes: Mississippi: Calhoun Co. , spring 13 mi NW Bruce, 20 February 1981, J. Goddard, 2♂, 11♀ ( UM). Yalobusha Co. , Denly Spring #1, near Air Mount Road, 33.97216° N, 89.55018° W, 24 October 2009, A. Harrison, 10♂, 7♀ ( INHS). Yalobusha Co. , spring near Air Mount Road, 33.96986° N, 89.55762° W, 24 October 2009, A. Harrison, 1♀ ( BPS). Yalobusha Co. , spring near county road 215, Benwood, 33.97635° N, 89.55013° W, 24 October 2009, A. Harrison, 1♀ ( BPS). Yalobusha Co. , Rockhouse Spring, 33.53458° N, 89.30257° W, 8 February 2009, A. Harrison, 9♂, 5♀ ( BPS). Yalobusha Co. , Coleman Spring, 33.53147° N, 89.32648° W, 23 December 2008, 1♂ ( AH). Same site, 16 January 2009, A. Harrison, 4♂, 3♀ ( AH). Same site, 31 January 2009, A. Harrison, 6♂, 1♀ ( BPS). Same site, 3 October 2009, A. Harrison, 7♂, 5♀ ( BPS). Same site, 16 January 2010, A. Harrison, 1♂ ( BPS). Yalobusha Co. , 2 nd tributary of Coleman Spring, 21 September 2009, A. Harrison, 3♂, 3♀ ( AH). Other material: Mississippi: Yalobusha Co., Coleman Spring , 23 December 2008, A. Harrison, 1 larva ( AH) . Same site, 3 October 2009, A. Harrison, 3 larvae ( BPS). Same site, 16 January 2010, A. Harrison, 5 larvae ( BPS) .

Adult habitus. General color dark brown without distinctive head pattern. Wings brown, legs pale brown. General appearance typical of genus.

Male. Forewing length 6-6.5 mm (N=10). Epiproct sclerite mushroom shaped; median sclerite on tergum 9 large, covering most of field. Anterior margin of tergum 8 bearing a low, triangular lobe; posterior margin of lobe typically rounded ( Figs. 1 , 6 ). Outer lobes of paraprocts shorter than inner lobes, broad in basal third ( Fig. 2 ), but narrowed in remainder and curved forward in apical third to form a blunt hook ( Figs. 8-10 ). Inner paraproct lobes (specilla) somewhat cylindrical in anterior aspect ( Fig. 1 ), widest basally and tapered to a bluntly rounded knob (ca. 38µm wide) ( Figs. 1 , 7 ); from lateral aspect ( Fig. 9 ) the inner lobes are straight along their dorsal (anterior) margins and smoothly curved along their ventral margins to a bluntly rounded apex. Outer subapical margins of inner paraproct lobes bear a cluster (3-6) of low rounded tubercles (ca. 4.5-6 µm long), and caudoventral margins bearing a series (2-5) of slightly smaller, additional tubercles beginning near the apex and continuing along caudoventral keel ( Figs. 7-11 ). Vesicle on sternum 9 small and triangular ( Fig. 2 ).

Female. Forewing length 7-7.5 mm (N = 5). Subgenital plate projects over base of sternum 9 ( Fig. 3 ). Posterior margin of plate bearing a median notch, slightly expanded mediolaterally; lobes truncate and conspicuously hairy. Spermathecal sclerite dark brown, semicircular in dorsal aspect with long, slender ventrolateral blade-like structures ( Figs. 4-5 ).

Larva. Pre-emergent body length 6-7 mm (N = 4). General color pale brown with obscure pattern on head; occiput with faint, irregularly elongate mottled areas and ocellar area often with a slightly darker median T-shaped line ( Fig. 41 ). Pronotum bearing 4-6 mixed length setae at anterolateral corners and 1-2 finer setae at posterolateral corners ( Fig. 41 ); mesonotum with a few short anterolateral setae, wingpads bare. Apical abdominal segments with posterolateral fringe row well developed and consisting of close-set, short thick setae ( Fig. 42 ); intercalary setae short, thick and restricted to posterior half of each tergum, sterna typically bare except for a single long seta on sternum 9. Paraprocts with heavy fringe of short, thick marginal setae. Cerci with ca. 20 segments; posterior margins of basal segments with apical fringe composed of short setae which become progressively longer through ca. segment 14, longer setae more numerous laterally; setal fringe on apical cercal segments consisting of a few, often only one, seta ( Figs. 43-44 ).

Diagnosis. This species is a member of the L. ferruginea subgroup and is difficult to distinguish from L. ferruginea proper using dissecting microscopes, but the two species may be resolved with compound microscopy (400X) or scanning electron microscopy. Because the lectotype (and two paralectotypes, Kimmins 1970) from Nova Scotia (British Museum of Natural History) of L. ferruginea are females designated by Ricker (1938), we sought male specimens of the L. ferruginea complex from Nova Scotia (the type locality) and other Canadian and New England localities to assist in resolving the identity of L. ferruginea ( Walker 1852) and its synonym, L. decepta Claassen (1923) described from the Ithaca, New York area. R.W. Baumann, B.C. Kondratieff and J.I. Earle graciously provided specimens from Nova Scotia, Newfoundland, New York, New Jersey, Pennsylvania and Tennessee which we examined with SEM. Several images ( Figs. 18-23 ), provided for comparison, indicate the paraprocts for L. ferruginea are similar in shape to those of L. colemanorum but the apical armature in the former species consists of 1-3 apicolateral, small spurs; typically these spurs are slightly longer and hooked laterad (as shown in Fig. 8 of Harper & Harper 2003) rather than consisting of low rounded tubercles of the type found in L. colemanorum . Nova Scotia specimens, presumed to be typical for the species, show 2 or 3 hooked apical spurs as in Figs. 18-19 , and specimens from two New York localities ( Figs. 21-22 ) are also similar in this respect. Some specimens from the northeast may also bear one or more caudoventral tubercles but the grouping, position and shape of the major spurs appears to be distinctive. Images are also provided for specimens of L. ferruginea found at Mississippi ( Figs. 15-17 ) and Tennessee sites. These southern specimens, and those from Washington Parish, Louisiana, typically have only one major dorsoapical spur and often a smaller, distal spur or tubercle. The larva ( Figs. 41-44 ) is identified as L. ferruginea using Harper & Hynes (1971) but in the few specimens available, the new species has almost no setae on the basolateral margins of the mesonotum whereas L. ferruginea is shown with a small setal cluster in this position by Harper & Hynes (1971). In addition, L. ferruginea has at least one seta shown in profile on several ventral abdominal segments and in L. colemanorum specimens these are absent, except for sternum 9. Larvae of the new species are also quite similar to those of L. szczytkoi , but that species also has several basolateral setae on the mesonotum and a single ventral seta on sterna 8 and 9 (DeWalt & Stark 1996).

Etymology. The species name honors Elizabeth and Red Coleman, grandparents of the senior author, and landowners of the Coleman Spring site where the species was discovered.

Comments. Collections of the new species are from seven different springs (8 total sites) in Yalobusha and Calhoun counties, Mississippi, all located on private property. These springs drain into tributaries of the Skuna River or the Yalobusha River above Grenada Reservoir. The Yalobusha and Skuna are tributaries of the Yazoo River system of northwestern Mississippi. Adults were present between 21 September and 8 February.

Figures

Figs. 1-5. Leuctra colemanorum. 1. Male terminalia, dorsal. 2. Male terminalia, ventral. 3. Female terminalia, ventral. 4. Spermathecal sclerite, oblique dorsal aspect. 5. Spermathecal sclerite, lateral, anterior margin on right. (es = epiproct sclerite; ip = inner lobe of paraproct; op = outer lobe of paraproct; sl = lobe of subgenital plate; tl = tergal lobe; v = vesicle)

Figs. 6-11. SEM images, Leuctra colemanorum male structures, Coleman Spring, Yalobusha Co., Mississippi. 6. Process on abdominal tergum 8. 7. Paraprocts, anterodorsal aspect. 8. Apex of paraprocts, anterodorsal aspect. 9. Paraprocts, lateral aspect. 10. Paraprocts, caudoventral aspect. 11. Paraproct apex, caudoventral aspect.

Figs. 12-17. SEM images, Leuctra spp. male paraprocts. 12. L. colemanorum, 13 mi NW Bruce, Calhoun Co., Mississippi, caudoventral aspect. 13. L. colemanorum, Denly Spring #1, Yalobusha Co., Mississippi, anterodorsal aspect. 14. L. colemanorum, Denly Spring #2, Yalobusha Co., Mississippi, anterodorsal aspect. 15. L. ferruginea, tributary Tom Way Branch, Amite Co., Mississippi, anterodorsal aspect. 16. L. ferruginea, Woods Spring, Choctaw Co., Mississippi, anterodorsal aspect. 17. L. ferruginea, Mill Creek, Simpson Co., Mississippi, anterodorsal aspect.

Figs. 41-44. Leuctra colemanorum larva. 41. Head, pronotum and mesonotum. 42. Abdominal segments 7-10, lateral. 43. Dorsal aspect of cercus, outer margin to right. 44. Lateral aspect of basal, mid and apical cercal segments.

Figs. 18-23. SEM images, Leuctra ferruginea male paraprocts. 18. NE Margaree River, Inverness Co., Nova Scotia, anterodorsal aspect. 19. Nova Scotia, Inverness Co., apex, anterodorsal aspect. 20. Nova Scotia, Inverness Co., apex, lateral aspect. 21. North Branch Saramac River, Franklin Co., New York, apex, anterodorsal aspect. 22. Governor Brook, Hamilton Co., New York, apex, anterodorsal aspect. 23. Doghobble Branch, Sevier Co., Tennessee, apex, anterodorsal aspect.