Nesticus bishopi 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 bishopi Gertsch, 1984

Figs 60A-D , 61A-H

Nesticus bishopi Gertsch, 1984: 33, figs 147-149.

Material examined.

Type material: Holotype: USA - North Carolina , Macon Co. • ♀ holotype; Highlands ; 6 Apr. 1929; S.C. Bishop leg.; AMNH; New collections from near type locality: - North Carolina , Macon Co. • ♂, 8♀; below Glenn Falls , SW of Highlands; 35.0312°N, - 83.2383°W; 2 Aug. 1992; M. Hedin leg.; • ♂, ♀; below Glenn Falls , SW of Highlands; 35.0312°N, - 83.2383°W; 31 Aug. 2002; M. Hedin, M. Lowder, P. Paquin leg.; MCH 02_175; Non type material: - Georgia, Rabun Co. • 2♀; Holcomb Branch of Holcomb Creek , off Hale Ridge Road, NE of Rabun Bald; 34.9831°N, - 83.2661°W; 14 Apr. 1992; T. McGarity leg.; • 2♂, 3♀; Hwy 246/106 along Mud Creek , NE of Dillard; 34.9924°N, - 83.3385°W; 19 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg.; MCH 07_126; • 2♂, ♀; Hwy 76 at Chattooga River crossing, confluence with Pole Creek ; 34.8172°N, - 83.3061°W; 2 Sep. 2002; M. Hedin, F. Coyle, M. Lowder, P. Paquin leg.; MCH 02_181; - North Carolina , Jackson Co. • ♀; along Chattooga River , NE side between Scotsman and Glade Creek; 35.0123°N, - 83.1164°W; 13 Jul. 1992; B. Dellinger leg.; - North Carolina , Macon Co. • ♂, 8♀; 4.3 mile S Standing Indian campground, along Nantahala River ; 35.0347°N, - 83.5057°W; 10 Aug. 1992; M. Hedin leg.; • ♀, 5 imm; 4.3 mile S Standing Indian campground, along Nantahala River ; 35.0347°N, - 83.5057°W; 20 Aug. 2002; M. Hedin, F. Coyle, M. Lowder, P. Paquin leg.; MCH 02_140; • 2♂, 5♀, 2 imm; along Black Creek , NE side Chunky Gal Mountain ; 35.092°N, - 83.5663°W; 20 Aug. 2002; M. Hedin, F. Coyle, M. Lowder, P. Paquin leg.; MCH 02_141; • 2♀; Coweeta Hydrological Lab, along Shope Fork of Coweeta Creek, FR 751; 35.0611°N, - 83.4447°W; 19 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg.; MCH 07_125; • ♂; Coweeta Hydrological Lab, along Shope Fork of Coweeta Creek , W of Otto; 35.0601°N, - 83.4547°W; 23 Oct. 2012; M. Hedin, J. Bond leg.; MCH 12_043; • 2♀; FR 710, 2 mi. N Deep Gap; 35.0425°N, - 83.555°W; 20 Aug. 2002; M. Hedin, F. Coyle, M. Lowder, P. Paquin leg.; MCH 02_142; • 9♀; near Dry Falls , Cullasaja River, off Hwy 64 NW of Highlands; 35.069°N, - 83.239°W; 11 Aug. 1992; M. Hedin leg.

Diagnosis.

Compared to other members of the challenging Nesticus reclusus subgroup, Nesticus bishopi is similar in detail in all aspects of male and female morphology to N. stupkai (compare Figs 60A-D , 61A-H , 62A-H ). Shared male features include a distal tegular apophysis shoe-shaped with a beak-like tip, base of distal part with a sclerotized and blade-like shoulder, proximal fork of tegular apophysis arrowhead-like, median apophysis short and triangular, paracymbium with translucent bladelike paradistal process, distal process with twisted tip, and toothlike distomedial process directly adjacent to small flange-like ventromedial process. Although we cannot find morphological characters that distinguish N. bishopi from N. stupkai , we retain both as distinct based on diagnostic DNA characters and an allopatric distribution (see further arguments in the Discussion). Both species are easily distinguished from closely-related N. reclusus by the shape of the male median and tegular apophyses (Figs 63A-F , 64A-F ).

Description of ♂ from near type locality

(MCH specimen #1078). Carapace dusky cream to orange, conspicuous faint dark pigment behind ocular area. Legs pale yellow to cream. Abdomen dirty pale cream, faint paired lateral pigmentation blotches. Eyes approximately equal in size, except for AMEs, ~ 1/3 width of ALEs. Eyes with rings of dark pigment. CL 1.3, CW 1.1, abdomen length 1.75, total body length 3.05. Leg I total length 9.75 (2.65, 0.55, 2.95, 2.5, 1.1), leg formula 1423, leg I / CW ratio 8.9. Palp with broadly S-shaped tegular apophysis, distal part shoe-shaped with a beak-like tip, base of distal part with a sclerotized and blade-like shoulder. Basal fork of tegular apophysis like a sclerotized broad-based arrowhead (Fig. 60A-D ). Median apophysis short and triangular. Conductor tip bent, surrounded by small funnel-shaped cuticular sheath. Paracymbium with translucent bladelike paradistal process, distal process with twisted, tubular tip; well-sclerotized, toothlike distomedial process directly adjacent to small flange-like ventromedial process (Fig. 60A-D ).

Variation.

Males and females from both sides of the Little Tennessee River barrier (see below) share very similar genitalic morphologies (Figs 60A-D , 61A-H ).

Distribution and natural history.

From montane habitats in southern North Carolina and northern Georgia. Populations are found both east (Cowee Mountains, including the type locality) and west (Nantahala Mountains) of the Little Tennessee River, a known dispersal barrier in other arachnid taxa (e.g., Thomas and Hedin 2008; Keith and Hedin 2012; Hedin and McCormack 2017). Western populations (Black Creek Road, Standing Indian, Coweeta, Deep Gap Road) indeed form a subclade on mitochondrial trees (Fig. 6 ).

As an example of natural history, 1992 collections near Standing Indian Campground were made in a northwest-facing rocky ravine, where many specimens were collected "in dark ravine, wet, deep litter, rocks, Rhododendron ".

Nesticus bishopi has been collected from locations very near N. dellingeri in the Chattooga River gorge (locations near Scotsman Creek; Fig. 53 ), suggesting that these species might somewhere be syntopic in this area.

Remarks.

The species is obviously morphologically very similar to a disjunct Nesticus stupkai and is arguably conspecific from a morphological perspective. We have retained N. bishopi as distinct at the species level because this taxon is monophyletic on both UCE and mitochondrial trees (Figs 3 , 4 , 6 ), and is geographically disjunct from sister species N. stupkai . One complication is that N. stupkai is paraphyletic with respect to N. bishopi on nuclear trees (Figs 3 , 4 ), as further discussed below.

We have made extensive collections of other Nesticus taxa in the region that separates N. bishopi from N. stupkai , finding only other Nesticus species (e.g., N. silvanus , N. cherokeensis , etc.; Fig. 53 ). As such, we view the probability of on-going gene flow as low.

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 60. Nesticus bishopi ♂ palps. North Carolina, Macon Co., below Glenn Falls, MCH specimen # 1078, dorsal (A), ventral (B) C Georgia, Rabun Co., Chattooga River at confluence with Pole Creek, MCH 02 _ 181, ventral D North Carolina, Macon Co., along Black Creek, MCH 02 _ 141, ventral. Scale bar: 0.5 mm.

Figure 61. Nesticus bishopi epigynal variation. North Carolina, Macon Co., below Glenn Falls, MCH specimen # 1071, ventral (A), dorsal (B). Georgia, Rabun Co., Chattooga River at confluence with Pole Creek, MCH 02 _ 181, ventral (C), dorsal (D). North Carolina, Macon Co., along Black Creek, MCH 02 _ 141, ventral (E), dorsal (F). North Carolina, Jackson Co., along Chattooga River, between Scotsman and Glade Creek, MCH specimen # 2016, ventral (G), dorsal (H). Scale bar: 0.5 mm.

Figure 62. Nesticus stupkai genitalia. Tennessee, Blount Co., Blowing Cave, NE of Townsend, MCH specimen # 1555, ♂ palp, ventral (A), dorsal (B) C Tennessee, Blount Co., Great Smoky Mountains NP, White Oak Sinks, holotype ♂ palp, ventral. Tennessee, Blount Co., Blowing Cave, MCH specimen # 1567, epigynum, ventral (D), dorsal (E). Tennessee, Blount Co., Great Smoky Mountains NP, Little River at Mile 40 of Hwy 73, MCH specimen # 1305, epigynum, ventral (F), dorsal (G). Tennessee, Blount Co., Great Smoky Mountains NP, White Oak Sinks, MCH specimen # 1304, epigynum, ventral (H), dorsal (I). Scale bar: 0.5 mm.

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.