Nesticus reclusus Gertsch, 1984

Hedin, Marshal & Milne, Marc A., 2023, New species in old mountains: integrative taxonomy reveals ten new species and extensive short-range endemism in Nesticus spiders (Araneae, Nesticidae) from the southern Appalachian Mountains, ZooKeys 1145, pp. 1-130 : 1

Nesticus reclusus Gertsch, 1984

Figs 63A-G , 64A-L , 65A-F , 66A-K

Nesticus reclusus Gertsch, 1984: 29, figs 75-78, 109-111.

Nesticus cooperi Gertsch, 1984: 30, figs 132-134, 144-146. syn. nov.

Material examined.

Northeastern locations: Type material: Holotype: USA - North Carolina, Swain Co. • ♂ holotype; Andrew’s Bald, Great Smoky Mountains National Park ; no date given; W.M. Barrows leg.; AMNH; Non type material: - North Carolina, Swain Co. • 8♂, 4♀; Great Smoky Mountains NP, Clingman's Dome , vicinity Forney Ridge parking area; 35.5558°N, - 83.496°W; 20 Aug. 1992; M. Hedin leg.; • 2♀; Great Smoky Mountains NP, Deep Creek , 0.25 mi. above Deep Creek CG, N Bryson City ; 35.4644°N, - 83.4344°W; 14 Aug. 1992; M. Hedin leg.; • ♀, 1 imm; Great Smoky Mountains NP, Hwy 441 E Thomas Ridge, 6.4 mi. N Smokemont CG turnoff; 35.6°N, - 83.4091°W; 26 Aug. 2005; M. Hedin, R. Keith, J. Starrett, S. Thomas leg.; MCH 05_091; • 9♀; Great Smoky Mountains NP, Noland Creek at Laurel Branch, off Fontana Road, W of Bryson City; 35.4582°N, - 83.5293°W; 26 Aug. 2005; M. Hedin, R. Keith, J. Starrett, S. Thomas leg.; MCH 05_093; • ♂; Hwy 129, NE of Cheoah Dam along Cheoah Reservoir; 35.4554°N, - 83.9254°W; 17 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg.; MCH 07_116; - Tennessee, Sevier Co. • ♂; Great Smoky Mountains NP, Elkmont Area ; 35.6536°N, - 83.5802°W; 31 Jul. 2000; M. Hedin, J. Cokendolpher leg.; MCH 00_144; • 2♂, 5♀; Great Smoky Mountains NP, Hwy 441 0.8 mi. N Newfound Gap; 35.62°N, - 83.4197°W; 20 Aug. 1992; M. Hedin leg.; • ♂; Great Smoky Mountains NP, Lower Baskins Creek ; 35.6957°N, - 83.4823°W; B. Dellinger leg; • ♂; Great Smoky Mountains NP, N side of Mt Buckley , W of Clingman’s Dome; 35.5626°N, - 83.5058°W; 21 Oct. 2012; M. Hedin, J. Bond, F. Coyle, S. Cameron leg.; MCH 12_039; • 3♀; Wear Cove, Myhr Cave ; 2 Aug. 2000; M. Hedin, J. Cokendolpher, W. Reeves leg.; MCH 00_148; • 2♂, ♀; Wear Cove, Myhr Cave ; 29 Aug. 2001; M. Hedin, M. Lowder, P. Paquin leg.; MCH 01_182.

Southwestern locations: USA - North Carolina: Swain County, Lost Nantahala Cave, near Nantahala , 17 May. 1979, coll. P.T. Hertl, S.P. Plantani, C.O. Holler (♂ holotype of Nesticus cooperi ) . - Georgia, Gilmer Co. • ♂, 2♀; Rock Creek Road, N of Rich Mountain Wilderness , 3 mi. E Cherry Log at Hwy 76; 34.7811°N, - 84.3339°W; 15 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg. ; MCH 07_102; - Georgia, Towns Co. • 12♀, 3 imm; 180 spur to Brasstown Bald ; 34.8593°N, - 83.8008°W; 21 Aug. 2002; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 02_147; • 2♀; 180 spur to Brasstown Bald ; 34.8593°N, - 83.8008°W; 15 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg. ; MCH 07_104; - North Carolina, Cherokee Co. • 3♂, 4♀; Beaver Creek Road, along Beaver Creek , N of Andrews; 35.2152°N, - 83.8327°W; 18 Aug. 2004; M. Hedin, R. Keith, J. Starrett, S. Thomas leg. ; MCH 04_057; • ♂, 3♀; Junaluska Road along Junaluska Creek , SE of Andrews; 35.176°N, - 83.768°W; 18 Aug. 2004; M. Hedin, R. Keith, J. Starrett, S. Thomas leg. ; MCH 04_059; • ♂; Junaluska Road along Junaluska Creek , SE of Andrews; 35.176°N, - 83.768°W; 18 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg. ; MCH 07_122; • 2♂, 4♀, 2 imm; Tatham Gap Road, S of Tatham Gap, N of Andrews ; 35.2495°N, - 83.8154°W; 18 Aug. 2004; M. Hedin, R. Keith, J. Starrett, S. Thomas leg. ; MCH 04_058; • ♂, 2♀; Watkins Creek Road, off Hwy 19, SW of Topton; 35.2312°N, - 83.7204°W; 19 Aug. 2004; M. Hedin, R. Keith, J. Starrett, S. Thomas leg. ; MCH 04_066; - North Carolina, Clay Co. • ♂, 8♀, 3 imm; along Fires Creek , NE Omphus Ridge; 35.1099°N, - 83.8267°W; 21 Aug. 2002; M. Hedin, F. Coyle, M. Lowder, P. Paquin leg. ; MCH 02_145; • ♂, 4♀; Tusquitee Mountains, Fires Creek, Long Branch , just up from Short Branch ; 35.1467°N, - 83.7618°W; 21 Aug. 2002; M. Hedin, F. Coyle, M. Lowder, P. Paquin leg. ; MCH 02_144; - North Carolina, Graham Co. • 3♂, 13♀, 11 imm; 0.25 mi. S Stecoah Gap on Appalachian Trail, off Hwy 143, Cheoah Mountains , NE of Cheoah; 35.353°N, - 83.7187°W; 28 Aug. 2002; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 02_165; • 3♂, 8♀, 7 imm; along Panther Creek at Cook Branch confluence, N of Grassy Gap; 35.3677°N, - 83.6272°W; 28 Aug. 2002; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 02_167; • ♀; Franks Creek, along Franks Creek Road , E of Sweetgum; 35.3158°N, - 83.7361°W; 18 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg. ; MCH 07_121; • ♂, 2♀, 3 imm; Hwy 28, 0.6 mi. E entrance to Cable Cove campground; 35.4234°N, - 83.7514°W; 28 Aug. 2002; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 02_166; • 3♂, 4♀; Hwy 28, ENE of Fontana Village, N side Yellow Creek Mountains ; 35.4387°N, - 83.8122°W; 18 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg. ; MCH 07_120; • 5♀; Panther Creek , FT 405; 35.3683°N, - 83.6267°W; 18 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg. ; MCH 07_119; • ♂, 8♀, 4 imm; Snowbird Mountains, N Tatham Gap, head of Long Creek on FR 423; 35.2579°N, - 83.8196°W; 27 Aug. 2002; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 02_162; • ♂, ♀; south of Stecoah Gap on Appalachian Trail, Cheoah Mountains , NE of Cheoah; 35.3546°N, - 83.7186°W; 18 Jul. 1991; B. Dellinger leg. ; - North Carolina, Macon Co. • 29♀, 10 imm; Ball Road , SE of Beechertown; 35.2687°N, - 83.6672°W; 30 Aug. 2002; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 02_172; • ♂, 3♀; Ball Road , SE of Beechertown; 35.2687°N, - 83.6672°W; 21 Aug. 2004; M. Hedin, R. Keith, J. Starrett, S. Thomas leg. ; MCH 04_072; • 2♀; Jarrett Creek , W of Wayah Gap; 35.1587°N, - 83.6349°W; 18 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg. ; MCH 07_123; • ♀; just N Jarrett Bald, above Wine Spring Creek ; 35.1777°N, - 83.6302°W; 1 May. 1993; B. Dellinger leg. ; • 6♀; Nantahala River Gorge, SE of Hwy 74 19W, on Ball Road (also called Wayah Road ); 35.2613°N, - 83.6608°W; 10 Aug. 1992; M. Hedin leg. ; • ♀; Nantahala River Gorge, vicinity Patton's Run Overlook ; 35.278°N, - 83.681°W; 29 Aug. 2001; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 01_183; • 2♂, ♀, 8 imm; S Burnington Gap, head of Ben Creek ; 35.2185°N, - 83.5639°W; 30 Aug. 2002; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 02_170; • ♂, 2♀, 12 imm; S of Wayah Bald on FR 388, 0.9 mi. S Wayah Road; 35.1559°N, - 83.5512°W; 30 Aug. 2002; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 02_169; • ♀; Wine Spring Creek, E Nantahala Lake off Wayah Bald Road , S of Aquone; 35.1913°N, - 83.6381°W; 25 Mar. 1993; B. Dellinger leg. ; - North Carolina, Swain Co. • 2♀; Nantahala River Gorge, 0.25 mi. downstream from Blowing Spring, Hwy 19W; 35.3307°N, - 83.6272°W; 18 Apr. 1994; M. Hedin leg. ; • ♂, 2♀; Nantahala River Gorge, E side of River along Hwy 19W, across from Talc Mountain quarry, NE of Hewitt; 35.312°N, - 83.6406°W; 8 Apr. 1993; B. Dellinger leg.

Diagnosis.

Male palps of Nesticus reclusus are easily distinguished from close phylogenetic relatives N. stupkai and N. bishopi . In N. reclusus the distal tegular apophysis is shaped differently and has a blunt or forked tip, the space separating the distal from basal parts of the tegular apophysis is itself wide, and the median apophysis is shaped differently, with a spatulate basal end and a blade-like distal tip (Figs 63A-G , 64A-L ). Females of these three species are challenging to diagnose; see comments above regarding the orientation of the dorsal epigynal plates.

Variation.

We here discuss and distinguish Nesticus reclusus populations as “northeastern” vs. “southwestern”, separated by the Little Tennessee River, including the Little Tennessee River Gorge and Fontana Lake (Fig. 53 ). The type locality for N. reclusus is in the northeast, at Andrew’s Bald in Great Smoky Mountains National Park. Southwestern populations surround and include the type locality of N. cooperi in the Nantahala River Gorge. We hypothesize that the Little Tennessee River might act as a dispersal barrier and promote divergence, although as discussed below combined evidence does not support this hypothesis.

In the northeast we examined males from seven locations in addition to the type locality, noting minimal palpal variation (Fig. 63A-G ). One male from Lower Baskins Creek possessed a palp with a translucent bladelike paradistal process slightly wider at the base, and mostly lacking a ventromedial paracymbial process. Females from the northeast have conspicuously dark spermathecae and (viewed dorsally) the dorsal-projecting internal anterior plates are well sclerotized (Fig. 65A-F ).

In the southwest we examined males from eighteen separate locations. All southwestern males approximated character conditions seen in northeastern males for all but one character. Males from eight locations possessed a paracymbium with the paradistal process lacking (and distomedial process moving towards the edge; Fig. 64I-L ), like the condition seen in type N. cooperi ( Gertsch 1984, figs 132-134). These locations included Fires Creek (MCH 02_144, MCH 02_145), Ben Creek (MCH 02_170), Wayah Bald (02_169), Ball Road (MCH 04_072), Panther Creek (02_167, 07_119), Junaluska Road (MCH 04_059, MCH 07_122) and Nantahala River Gorge (1993 collection, very near the type locality of N. cooperi ). These locations are geographically contiguous, found mostly along the western flanks of the Nantahala Mountains including the Nantahala River Gorge (Fig. 53 ).

Females from southwestern populations vary slightly (Fig. 66A-K ), but those from sample locations with " N. cooperi -like" males (Fig. 66I-K ) are not obviously different from other populations. That is, we could not discern a distinctive " N. cooperi -like" female morphology.

Distribution and natural history.

This relatively wide-ranging montane species occurs from the northern side of the Great Smoky Mountains National Park, southwestward across the Little Tennessee River to the Yellow Creek, Cheoah, Snowbird, Nantahala, Valley River, and Tusquitee Mountains (Fig. 53 ). Two conspicuously disjunct populations occur even further south, in northern Georgia at Brasstown Bald and Rock Creek Road (Fig. 53 ). We comment more on the Rock Creek Road specimens below.

We hypothesize that the geographic gap north and northeast of Fontana Lake in the Great Smoky Mountains is an artifact of poor sampling, as this region is mostly roadless (Fig. 53 ). As such, northeastern vs. southwestern populations should be approximately contiguous, except for the river barrier itself. This differs from the situation in Nesticus bishopi versus N. stupkai , where we view the geographic disjunction as real (Fig. 53 ).

As an example of natural history, at Ball Road (MCH 02_172) a team collected 29 females and ten immatures in a 30-minute devoted survey from beneath rocks in a south-facing boulderfield. As mentioned above, Nesticus reclusus (♂, 4♀) was found in syntopy with N. lowderi (3♂, 5♀) at Fires Creek (MCH 02_144).

See comments above regarding the unlikely Gertsch (1984) record of N. reclusus from " McDowell County, Montreat ". Despite extensive collections we have never found members of the Nesticus reclusus group from east of the Asheville Basin (Fig. 53 ).

Remarks.

Gertsch (1984) described both Nesticus reclusus and N. cooperi , distinguishing males by the shape of the basal tegular apophysis and the shape / presence of a paradistal paracymbial process (Gertsch referred to this as a dorsal process; see our comments above). Importantly, although Gertsch examined many records for montane N. reclusus , he only had N. cooperi specimens from two adjacent Nantahala River Gorge populations. Our geographic sampling has greatly expanded the distribution for southwestern N. reclusus , including many locations surrounding the type locality of N. cooperi . With this greater sampling we found that male morphology varies slightly with geography, particularly in the presence of the paradistal paracymbial process. We could not discern the shape differences in the basal tegular apophysis that Gertsch (1984) noted (Figs 63 , 64 ). From a morphological perspective we view this as a single species with a relatively broad montane distribution, with minor male morphological variation across this distribution.

Nuclear phylogenomic data is mostly consistent with this single species hypothesis, except for the southern disjunct Rock Creek Road population, further discussed below. Only one " Nesticus cooperi -like" population was sampled for nuclear data (Nantahala River Gorge) and is embedded within a paraphyletic grade including both northeastern and other southwestern N. reclusus (Figs 3 , 4 ). The nuclear data within this complex are notable for many low gene and site CF values, and low local posterior probability values (Figs 3 , 4 ), suggesting extensive gene tree discordance.

The mitochondrial evidence is similarly challenging to interpret in this complex, as mitochondrial data do not support the larger Nesticus reclusus group as monophyletic, and species interrelationships diverge strongly from that suggested by the nuclear data (Fig. 6 ). Within Nesticus reclusus itself Noland and Clingmans sequences are recovered with N. stupkai sequences, separate from Smokemont and Newfound sequences. We hypothesize that this discordance is a result of mitochondrial introgression from N. stupkai into certain N. reclusus populations, where these taxa occur in geographic proximity. For example, sympatry in Myhr Cave is a potential conduit for mitochondrial gene exchange. Six sampled locations with a " N. cooperi -like" paracymbium do not form a clade on mitochondrial trees (Fig. 6 ).

The southern disjunct Rock Creek Road sample (Fig. 53 ) adds further intrigue to this complex. Mitochondrial sequences are highly divergent, falling with Nesticus sheari (Fig. 6 ), while nuclear sequences are sister to a clade including N. stupkai , N. bishopi , and remaining N. reclusus (Figs 3 , 4 ). At the same time, males from this location possess unremarkable palps, identical in detail to other southwestern N. reclusus palps (Fig. 64E, F ), and females are similarly morphologically unremarkable (Fig. 66G, H ). We suspect that gene flow across species boundaries (perhaps involving N. sheari ?) might be impacting results in this part of the Nesticus phylogeny. More geographic and UCE sampling in this geographic region will be needed to resolve this tricky taxonomic issue.

Figures

Figure 3. UCE concatenated maximum likelihood tree. Distant outgroups removed (for graphical purposes), specimen numbers correspond to those in Suppl. material 3 (with detailed location provided in Suppl. material 1). Node numbers correspond to bootstrap (bold text) / gCF / sCF. Only bootstrap values below 100 shown, all others 100. gCF and sCF values rounded to nearest integer; sCF values below 38 highlighted with red text.

Figure 4. UCE ASTRAL species tree. Distant outgroups removed (for graphical purposes), specimen numbers correspond to those in Suppl. material 3 (with detailed location provided in Suppl. material 1). Included are quartet support values (rounded to nearest integer), and local posterior probability values (if less than 1.0, red text). Branch lengths in coalescent units for internal branches only, terminal branch lengths arbitrary. Internal branch to Nesticus cressleri truncated for graphical purposes.

Figure 6. COI IQT gene tree. Distant outgroups trimmed. Specimen numbers correspond to those in Suppl. material 3 (with detailed location provided in Suppl. material 1). Sequences from UCE capture denoted with " NODE ". Populations with a " Nesticus cooperi - like " male paracymbium denoted by small circles. Not all tip bootstrap values shown (see Suppl. material 4 for. tre file with all bootstrap values).

Figure 53. A distribution of Nesticus reclusus group species B distribution of Nesticus jonesi. Type localities designated with yellow circles. State boundaries and major cities shown for geographic context. Dashed lines circumscribe known species distributions. The geographic distribution of " N. cooperi - like " populations is circled; this includes some female-only locations which are inside this distribution and included here only for purposes of graphical convenience.

Figure 63. northeastern Nesticus reclusus ♂ palps, ventral view (* except for G) A Tennessee, Sevier Co., Wear Cove, Myhr Cave, MCH 01 _ 182 (* right palp, inverted in Photoshop) B Tennessee, Sevier Co., Great Smoky Mountains NP, Lower Baskins Creek C Tennessee, Sevier Co., Great Smoky Mountains NP, Hwy 441, N of Newfound Gap D Tennessee, Sevier Co., Great Smoky Mountains NP, Elkmont Area, MCH 00 _ 144 E North Carolina, Swain Co., Great Smoky Mountains NP, south of Clingman's Dome, near Forney Ridge parking area F North Carolina, Swain Co., Great Smoky Mountains National Park, Andrew's Bald (male holotype, AMNH) G North Carolina, Swain Co., Cheoah Dam along Cheoah Reservoir (MCH 07 _ 116), dorsal view. Scale bar: 0.5 mm.

Figure 64. southwestern Nesticus reclusus ♂ palps. North Carolina, Graham Co., Appalachian Trail, S of Stecoah Gap, MCH 02 _ 165, ventral (A), dorsal (B) North Carolina, Graham Co., ENE of Fontana Village, MCH 07 _ 120, ventral (C), dorsal (D). Georgia, Gilmer Co., Rock Creek Road, N of Rich Mountain Wilderness, MCH 07 _ 102, ventral (E), dorsal (F). North Carolina, Cherokee Co., Beaver Creek Road, MCH 04 _ 057, ventral (G). North Carolina, Cherokee Co., S of Tatham Gap, MCH 04 _ 058, dorsal (H). North Carolina, Clay Co., Tusquitee Mountains, Long Branch of Fires Creek, MCH 02 _ 144, ventral (I), dorsal (J). North Carolina, Swain Co., Nantahala River Gorge, Nantahala River Gorge, across from Talc Mountain quarry, dorsal (K). North Carolina, Macon Co., S Wayah Bald, MCH 02 _ 169, dorsal (L). Scale bar: 0.5 mm.

Figure 65. northeastern Nesticus reclusus epigynal variation. North Carolina, Swain Co., Great Smoky Mountains NP, south of Clingman's Dome, vicinity Forney Ridge parking area, MCH specimen # 1973, ventral (A), dorsal (B). North Carolina, Swain Co., Great Smoky Mountains NP, N of Smokemont Campground turnoff, MCH specimen # N 1019, ventral (C), dorsal (D). North Carolina, Swain Co., Great Smoky Mountains NP, Noland Creek at Laurel Branch, MCH specimen # N 1051, ventral (E), dorsal (F). Scale bar: 0.5 mm.

Figure 66. southwestern Nesticus reclusus epigynal variation. North Carolina, Graham Co., Appalachian Trail, S of Stecoah Gap, MCH 02 _ 165, ventral (A), dorsal (B). North Carolina, Graham Co., ENE of Fontana Village, MCH 07 _ 120, ventral (C), dorsal (D). North Carolina, Cherokee Co., Beaver Creek Road, MCH 04 _ 057, ventral (E), dorsal (F). Georgia, Gilmer Co., Rock Creek Road, N of Rich Mountain Wilderness, MCH 07 _ 102, MCH specimen # N 1160, ventral (G), dorsal (H). North Carolina, Clay Co., Tusquitee Mountains, Long Branch of Fires Creek, MCH 02 _ 144, ventral (I), dorsal (J). North Carolina, Macon Co., Ball Road, SE of Beechertown, MCH 04 _ 072, ventral (K). Scale bar: 0.5 mm.