Nesticus lowderi, Hedin & Milne, 2023

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 lowderi sp. nov.

Figs 46A-D , 47A-H

Material examined.

Type material: Holotype: USA - North Carolina, Clay Co. • ♂ holotype; Chunky Gal Mountain, Chestnut Branch of Barnard's Creek ; 35.0857°N, - 83.6327°W; 6 May. 1999; M. Hedin, B. Dellinger leg.; MCH 99_016 (SDSU_TAC000667) ; Paratypes: - Clay Co. • 3♀; data as for holotype; Non type material: - Clay Co. • ♂; along Barnard's Creek , N side of Chunky Gal Mountain; 35.0868°N, - 83.6372°W; 24 Apr. 1992; B. Dellinger leg. ; • ♀; Eagle Fork Creek (Dave Barrett) SE of Shooting Creek N of Hightower Bald; 35.0075°N, - 83.6225°W; 20 Aug. 2002; M. Hedin, F. Coyle, M. Lowder, P. Paquin leg. ; MCH 02_143; • ♂, 6♀; Fires Creek Road, Picnic Area along Fires Creek; 35.0955°N, - 83.8586°W; 16 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg. ; MCH 07_108; • 3♂, 5♀; 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; • 2♀, 1 imm; Fires Creek , near Leatherwood Falls, just NE Fires Creek Picnic Area; 35.0961°N, - 83.8566°W; 18 Aug. 2004; M. Hedin, R. Keith, J. Starrett, S. Thomas leg. ; MCH 04_060; • 2♀; FR 440, along Big Tuni Creek , 2 mi. N Woods Road; 35.1025°N, - 83.7007°W; 16 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg. ; MCH 07_107; • ♂, 7♀, 7 imm; FR 440, Big Tuni Creek , E Tusquitee Bald near Bob Allison Picnic Area; 35.1463°N, - 83.6974°W; 30 Aug. 2002; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 02_171; • ♂; W side Chunky Gal Mountain , Hwy 64, near scenic overlook; 35.0627°N, - 83.6204°W; 6 May. 1999; M. Hedin, B. Dellinger leg. ; MCH 99_019; - Swain Co. • 2♀; Nantahala River Gorge, Blowing Springs Cave; 10 Sep. 2001; J.D. Mayes leg.

Diagnosis.

Several male features distinguish Nesticus lowderi from other members of the species group (and Appalachian clade), including the distinctive shape of the posterior keel of the forked tegular apophysis and the low sinuous paradistal process (Fig. 46A-D ). Median bars, extending V-shaped upwards from the median septum and interrupting the epigynal pockets, diagnose N. lowderi females from other members of the species group and other common regional taxa (e.g., N. reclusus ).

Description of ♂ holotype

(SDSU_TAC000667). Carapace cream-colored, faint gray pigmentation behind ocular area leading to midline. Legs pale yellow / cream. Abdomen with many dark gray blotches on a pale cream background. All eyes approximately equal in size, except for AMEs, ~ 1/2 width of ALEs. Eyes with rings of dark pigment. CL 1.32, CW 1.2, abdomen length 1.48, total body length 2.8. Leg I total length 9.88 (2.71, 0.58, 2.9, 2.59, 1.1), leg formula 1423, leg I / CW ratio 8.2. Ventral paracymbial process consists of a large, basal lobe that broadens down length of paracymbium. Distal process somewhat spoon-shaped, dorsal process a low lobe, and the paradistal process consists of a sinuous, prolaterally directed extension with a heavily sclerotized anterior edge. Median apophysis rectangular with an anteriorly directed point and a sclerotized prolateral edge. Tegulum forked, with strong posterior keel including a wide lobe with a flattened edge. Distal tegular process crescent-shaped with a heavily sclerotized point directed anterolaterally, closely appressed to median apophysis. Distal tip of conductor bent and directed prolaterally.

♂ Variation.

Males from different locations varied slightly in the shape of the basal fork of the tegular apophysis (Fig. 46A-D ).

Description of ♀ paratype

(SDSU_TAC000668). Carapace dusky cream to orange, with faint gray pigmentation behind ocular area leading to midline and around edges. Leg pale yellow / cream. Abdomen with paired dark gray blotches on a light gray background. All eyes approximately equal in size, except for AMEs, ~ 1/2 width of ALEs. Eyes with rings of dark pigment. CL 1.25, CW 1.11, abdomen length 1.46, total body length 2.71. Leg I total length 8.34 (2.41, 0.51, 2.39, 2.04, 0.99), leg formula 1423, leg I / CW ratio 7.5. Epigynal pockets interrupted by median bars that extend upwards V-shaped from base of median septum to nearly the top of the larger pocket (giving an overall appearance of an anchor, Fig. 47A-H ). The presence of these bars forms septal grooves that lie directly adjacent to the median septum, and smaller pockets lateral to the V-shaped bars. Median septum slightly protruding posteriorly past lateral lobes. Spermathecae elongated and curved along lateral borders of epigynum, approximately banana-shaped. Ventrolateral sides of epigynal plate bulging (convex), as viewed from the side. Viewed dorsally, large internal lobes extend anteriorly and possess sclerotized rims. Interior margins directed inward diagonally towards the center of the epigynum.

♀ Variation.

Epigynal structure fairly uniform across collecting locations (Fig. 47A-H ). Blowing Springs Cave females are concolorous and relatively long-legged.

Distribution and natural history.

Most populations are from the Chunky Gal, Tusquitee, and Valley River Mountains of western North Carolina (Fig. 42 ). Holler et al. (2020) attributed female specimens from Blowing Springs Cave to Nesticus cooperi (= N. reclusus ); we instead have identified these as N. lowderi based on epigynal morphology, including the inward curve of the internal plates (Fig. 47A-H ). This would represent a disjunct northern-most record for N. lowderi (Fig. 42 ) and should be confirmed with the collection of males and /or nuclear DNA data from this location. Another possibility is sympatry at this location.

At Fires Creek (MCH 02_144), Nesticus lowderi (3♂, 5♀) was found in syntopy with N. reclusus (♂, 4♀); field notes read "30-minute survey, 3 persons, S-facing and N-facing rock fields". Because we did not identify specimens directly in the field it remains unclear if these different species were truly syntopic or were segregated somehow at this location. Also, at least 15 immatures were collected at this location but were not identified to species because of sympatry.

Collection records suggest that this species is less common in the Chunky Gal Mountains than in the more westerly Tusquitee and Valley River Mountains.

Etymology.

This species is named to recognize and honor Michael Lowder, faculty member at Stanly Community College, native North Carolinian, fan of western North Carolina, and collector of many Appalachian Nesticus . Michael was the first graduate student of MH, who remains forever grateful for our continued friendship and reflects on our early lab and field time together with great fondness.

Remarks.

The extent of mitochondrial divergence observed in this taxon over a small geographic region (including only Chunky Gal, Tusquitee, and Valley River Mountains) is notable (Fig. 6 ).

Figures

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 42. Distribution of the Nesticus barrowsi group. Type localities designated with yellow circles. State boundaries and major cities shown for geographic context. Dashed lines circumscribe known species distributions.

Figure 46. Nesticus lowderi sp. nov. ♂ palps. North Carolina, Clay Co., Chunky Gal Mountain, Chestnut Branch of Barnard's Creek, MCH 99 _ 016 (SDSU _ TAC 000667), dorsal (A), ventral (B) C North Carolina, Clay Co., Big Tuni Creek, MCH 02 _ 171, ventral D North Carolina, Clay Co., Fires Creek Road, Picnic Area along Fires Creek, MCH 07 _ 108, ventral. Scale bar: 0.5 mm.

Figure 47. Nesticus lowderi sp. nov. epigynal variation. North Carolina, Clay Co., Chunky Gal Mountain, Chestnut Branch of Barnard's Creek, MCH 99 _ 016 (SDSU _ TAC 000668) ventral (A), dorsal (B). North Carolina, Clay Co., Big Tuni Creek, MCH 02 _ 171, ventral (C), dorsal (D). Swain Co., Blowing Springs Cave, ventral (E), dorsal (F). North Carolina, Clay Co., Fires Creek Road, Picnic Area along Fires Creek, MCH 07 _ 108, ventral (G). North Carolina, Clay Co., Dave Barrett Fork of Eagle Fork Creek, MCH 02 _ 143, ventral (H). Scale bar: 0.5 mm. Septal bars outlined in image G to better reflect actual specimen.