Remenus duffieldi Nelson & Kondratieff, 1995

(Figs. 70–87)

http://lsid.speciesfile.org/urn:lsid: Plecoptera .speciesfile.org: TaxonName:607

Remenus duffieldi Nelson & Kondratieff (1995: 600) .

Holotype ♂: Georgia, Towns County, Soapstone Creek, Rt. 180, nr. jct. Rt. 180 & Owl Cr. Rd., Chattahoochee National Forest (NMNH). Figures: adult–male terminalia (dorsal, lateral), female subgenital plate, ova (dorsal, ventral).

Remenus duffieldi: Kondratieff (2004: 164) . Figures: adult–figures from Kondratieff & Nelson (1995).

Remenus duffieldi: Stark (2017: 236) . Figures: larva– cercus (basal, middle).

Material examined: Georgia, Union Co., Rock Creek, Rte 69, 1.5 mi. W Hightower Gap, Chattahoochee National Forest, [N 34.67981, W 84.135914], 29 May 1990, R . M. Duffield, 2♂ (CSUIC, paratypes) . White Co., Andrews Creek, Rte 17/75, Andrews Cove Campground, [N 34.77817, W 83.73738], 2 June 1994, C.H. Nelson, 1♂, 1♀ (CSUIC, paratypes) . North Carolina, Haywood Co., Yellowstone Prong of East Fork Pigeon River, Graveyard Fields, BLRI , [ N 35.321966, W 82.845768, 17 June 2009, J. Robinson, 1♂ (CSUIC) . Macon Co., Nantahala River, [no GPS], 30 May 1939, Thelma Howell, 1L (INHS); Tellico Creek, Tellico Rd. [no GPS], 27 May 1993, B.P. Stark, R . Simmons, P. Kelly, 1♂ (CSUIC); Tellico Creek, Tellico Rd. ~ 0.5 mi. W of Sugar Cove Rd., N 35.27688, W 83.54347, 15 May 2017, C. Verdone, B.C. Kondratieff, 7♂, 7♀ (CSUIC) . Swain Co., Collins Creek, Collins Creek Picnic Area, Hwy 441, GRSM , N 35.56752, W 83.33663, 16 May 2017, C. Verdone, B.C. Kondratieff, 5♂, 2♀, 1L (CSUIC); Kanati Fork, Hwy 441, GRSM , N 35.58738, W 83.36297, 16 May 2017, C. Verdone, B.C. Kondratieff, 2♂ (CSUIC) . Transylvania Co., Pigeon Branch South Fork Mills River, NFR 1206, off Rte 276, [N 35.35815, W 82.77810], 8 July 1981, B.C. Kondratieff, 1♂, 2♀ (CSUIC) .

Additional records not examined. North Carolina, Haywood Co., Yellowstone Prong of East Fork Pigeon River, N 35.32814, W 82.82897, 26 May 2014, A.L. Sheldon 1♀ (WKUC); tributary to Flat Laurel Creek, TR 617, N 35.32303, W 82.89282, 22 July 2015, A.L. Sheldon, 1♂ (WKUC) .

Distribution. USA – GA, NC. (Fig. 69)

Male. (Fig. 70). Macropterous; forewing length 9.5– 10.4 mm (n = 10) (Fig. 71). Body length, 7.9–9.8 mm (n = 10). General body color pale yellow-gold with light brown markings. Dorsum of head typical of genus (Fig. 72). Pronotum pale, covered in regularly spaced setae, with light brown rugose areas, glabrous rugosities mediolaterally (Fig. 72); anterior and posterior margins brown (Fig. 72). Abdominal terga with a narrow mid-dorsal, dusky, interrupted brown stripe (Fig. 73); terga 1–4 pale yellow, terga 5–9 pale yellow to light brown; terga darkened laterally (Fig. 73); tergum 9 lacking sensilla basiconica (Fig. 74). Hemitergal lobes short, not separated from 10 th tergum, with long trichoid sensilla and 15–17 sensilla basiconica on each lobe (Figs. 74-77). Epiproct length ~ 382–420 μm; width ~ 136–168 μm (n = 3); epiproct flattened dorsoventrally (Figs. 75, 78), clothed in appressed hair-like spinulae, and with a mediodorsal sclerite (Figs. 74, 77–78); epiproct widest basally; hair-like spinulae of distal ¼ splayed (Fig. 79). Mediodorsal sclerite narrow throughout its length (slightly wider at its base) and barely exceeding the epiproct apex (Figs. 77–80); sclerite with a dorsal hump near distal ¼ (Figs. 77–79); apex smoothly rounded and glabrous (Fig. 80). Paragenital plates short, rounded, or triangular (Figs. 74, 77). Basal cowl covered in dense lightly pigmented spinulae (Figs. 74–75).

Female. Macropterous; forewing length 10.5–11.1 mm (n = 10). Body length, 8.9–10.4 mm (n = 10). General color and morphology similar to the male. Abdominal pigment pattern usually less developed. Medial dusky stripe is faint and lateral margins are not distinctly darkened. Subgenital plate broadly rounded, elongate, lightly sclerotized, with regularly spaced setae, extending ⅘ over sternum 9, or slightly beyond the posterior margin of sternum 9 (Fig. 81); basolateral crease nearly straight or convex posteriorly, extending ~ ⅓ length anteriorly into sternum 8 (Fig. 81).

Ovum. Shape typical of genus (Figs. 82–84). Length 444–446 μm; width 340–355 μm (n =3).

Larva. (Fig. 85). Body length 9.1 mm, (n = 1). Head (Fig. 86), lacinia (Fig. 87), mandibles (Fig. 88), and pronotum (Fig. 86) typical of genus. Mature male larva with a short triangular terminal process (developing epiproct) (Fig. 89), Basal cercal segments with whorls of short setae (Fig. 90).

Diagnosis. Remenus duffieldi is distinguished from all other Remenus species in coloration and genitalic structure. The pale pronotum and grayish wings are unlike any other species in the genus. The epiproct is most similar to R. bilobatus in that it has a dorsal sclerite, but in contrast, it does not greatly exceed the epiproct apex. Additionally, R. duffieldi is differentiated in that the epiproct is dorsoventrally flattened, tergum 9 is not divided, lacks sensilla basiconica, and the spinulae covering the basal cowl are pale. Whereas in males of R. bilobatus, the epiproct is flattened laterally, the 9 th tergum has a medial glabrous division, both terga 8 and 9 have mediolateral patches of sensilla basiconica and the basal cowl is clothed in dense golden-brown spinulae.

Females are distinguished by the distinctive pronotal coloration in addition to differences in the subgenital plate. In R. duffieldi, the subgenital plate is broadly rounded and elongate, generally, as long as, or longer than tergum 9. Whereas in R. bilobatus, the subgenital plate is either broadly triangular or broadly rounded and typically does not exceed the posterior margin of tergum 9.

Mature larvae of R. duffieldi are separable from the two other sympatric species, R. bilobatus and R. daniellae by the lack of long setae on the basal cercal segments. Remenus kirchneri also lacks long setae on the basal cercal segments, but based on presently available records, the ranges of these two species do not overlap with R. duffieldi occurring west of the French Broad River and R. kirchneri occurring to the east (Fig. 115).

Biological notes. No life history or biological studies have been conducted on this species. Remenus duffieldi is known from 11 locations in Blue Ridge Physiographic Province of Georgia and North Carolina. This species has been documented from 1 st –3 rd order streams with drainage areas ranging from 0.28–9.72 km 2. The average elevation of occurrence localities is 987.1 m (SD ± 346.1 m). Based on examined material, emergence occurs from mid-May to late July. Existing records are limited, but this species probably inhabits many other streams within GRSM, Nantahala and Chattahoochee-Oconee National Forests.