Leuctra hicksi, 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 : 23-26

Leuctra hicksi sp.n.

( Figs. 24-34 )

Material examined. Holotype ♂ and 3♂, 7♀ paratypes, Mississippi, Perry Co., Cypress Creek, Hwy 29, Camp Shelby , 31.07194° N, 89.00775° W, 23 December 2009, B. Stark (holotype INHS, paratypes BPS). Additional paratypes: Same site, 26 December 2007, M. Hicks, 1♂, 2♀ ( BPS, MH). Perry Co. , Ashley Creek / Cypress Creek, FR 3500, ~ 2 mi E Paret Lot Work Center, T1 N R10 W, Sec 5, 20 November 1996, R. E. DeWalt, 1♂, 5♀ ( INHS).

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

Male. Forewing length 5-5.5 mm (N = 4). Epiproct sclerite spade shaped; tergum 9 with a median, quadrangular sclerite, tergum 8 with a small, median, triangular sclerite; anterior margin of tergum 8 heavily sclerotized ( Fig. 24 ). Anterior margin of abdominal tergum 8 bearing an obscure, low, arcuate lobe, or lobe absent ( Figs. 24 , 29 ). Outer lobes of paraprocts very slender for most of length, but base expanded around base of inner lobe; apex strongly curved near the tip to form a blunt hook ( Figs. 30-31 ). Inner paraproct lobes broad at the base (ca. 70 µm wide) and abruptly narrowed to ca. 28 µm in apical third ( Figs. 25 , 32-33 ); apices of outer lobes bearing a single, apical, laterally-directed spine ca. 23 µm in length ( Figs. 30-33 ). Vesicle on sternum 9 small and triangular ( Fig. 25 ).

Female. Forewing length 6-7 mm (N = 5). Subgenital plate projects over base of sternum 9 ( Figs. 26 , 34 ). Posterior margin of plate bearing a median U-shaped notch; lobes of plate hairy along margin, gradually narrowed and ending in bluntly rounded tips; median and marginal areas of plate dark brown ( Fig. 26 ). Spermathecal sclerite dark brown, with expanded lateral blade-like structures ( Figs. 27-28 ).

Larva. Unknown.

Diagnosis. This species is a member of the Leuctra rickeri subgroup of the L. ferruginea species complex which includes L. alabama , L. paleo , L. rickeri James and L. szczytkoi . Within this group only L. hicksi has broad inner paraproct lobes in caudal and anterior aspect which narrow abruptly in the apical third ( Figs. 25 , 32 ).

Comparative images of the paraprocts and tergal lobes of specimens presumed to be L. alabama (Cold Spring, Madison Co., Alabama) and L. rickeri (Burden Creek, Pope Co., Illinois) are presented in Figs. 35-40 . The paraprocts of these are virtually identical suggesting only one of these species is valid. Additional images are also provided for specimens of L. paleo from a site near the type locality in Columbia Co., Arkansas ( Figs. 45-50 ), and for L. szczytkoi specimens collected at the type locality of Schoolhouse Springs, Jackson Parish, Louisiana ( Figs. 51-56 ). These images indicate the latter two species are also very similar, and probably synonymous, but they are clearly distinct from L. hicksi and other populations of the L. rickeri subgroup known from east of the Mississippi River. The spines on the inner lobes of the paraprocts of L. szczytkoi and L. paleo (range 48-55 µm) are ca. 2.5-3 times as long as those on paraprocts of L. hicksi and other eastern members of the subgroup (range 18-22 µm). In addition, in lateral aspect the eastern species have the inner lobes much narrower basally and broader and more rounded near the tips, and in caudal aspect the western species have an eroded appearance below the apical orifice ( Figs. 47-48 , 54 ), whereas the caudal surfaces of the eastern species are relatively smooth ( Figs. 37, 40 ).

Etymology. The patronym honors our friend and colleague, Matthew B. Hicks, for his frequent assistance and continued interest in Mississippi’s stoneflies. Matt first collected this species during our 2007 “winter stonefly blitz” and he generously made his specimens available for our study.

Comments. Cypress Creek at the type locality is a small blackwater stream about 1.5 m wide and 0.5 m deep. The stream is a tributary of Black Creek in the Pascagoula River Drainage Basin. Adults were collected using a beating sheet in riparian shrubbery. No larvae were found among the leaf packs examined.

Figures

Figs. 24-28. Leuctra hicksi. 24. Male terminalia, dorsal. 25. Male terminalia, ventral. 26. Female terminalia, ventral. 27. Spermathecal sclerite, dorsal. 28. Spermathecal sclerite, lateral.

Figs. 29-34. SEM images, Leuctra hicksi, Cypress Creek, Perry Co., Mississippi. 29. Male tergum 8. 30. Paraprocts, anterodorsal aspect. 31. Paraproct apex, anterodorsal aspect. 32. Paraproct apices, caudoventral aspect. 33. Paraproct apex, caudoventral aspect. 34. Female terminalia, ventral.

Figs. 35-40. Leuctra spp. male terminalia, SEM images. 35-37. L. alabama, Cold Spring, Madison Co., Alabama, and 38-40. L. rickeri, Burden Creek, Pope Co., Illinois. 35. Tergum 8. 36. Paraprocts, anterodorsal aspect. 37. Paraprocts, caudoventral aspect. 38. Male tergum 8. 39. Paraprocts, anterodorsal aspect. 40. Paraprocts, caudoventral aspect.

Figs. 45-50. Leuctra paleo male terminalia, SEM images. 45. Paraprocts, anterodorsal aspect. 46. Paraproct apices, anterodorsal aspect. 47. Paraprocts, caudoventral aspect. 48. Paraproct apices, caudoventral aspect. 49. Paraprocts, lateral aspect. 50. Tergum 8.

Figs. 51-56. Leuctra szczytkoi male terminalia, SEM images. 51. Paraprocts, anterodorsal aspect. 52. Paraproct apices, anterodorsal aspect. 53. Paraprocts, caudoventral aspect. 54. Paraproct apices, caudoventral aspect. 55. Paraprocts, lateral aspect. 56. Tergum 8.