Nesticus gertschi Coyle & McGarity, 1992

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 gertschi Coyle & McGarity, 1992

Fig. 39A-F

Nesticus gertschi Coyle & McGarity, 1992: figs 15-20.

Material examined.

Type material: Holotype: USA - Tennessee, Greene Co. • ♂ holotype; Cedar Creek Cave, 100 m into cave; 16 Mar. 1991; T. McGarity leg; AMNH; New collections from type locality: - Tennessee, Greene Co. • 2♂, 9♀; Cedar Creek Cave , 1 mi. S Cedar Creek; 21 Sep. 1992; M. Hedin, S. O’Kane leg. Non type material: - North Carolina, Buncombe Co. • ♂; 0.1 mi. NW Hickory Nut Gap Hwy 74, NW of Gerton; 35.4898°N, - 82.3627°W; 5 May. 1999; M. Hedin, B. Dellinger leg.; MCH 99_013; • ♂, ♀, 1 imm; 0.1 mi. NW Hickory Nut Gap Hwy 74, NW of Gerton; 35.4898°N, - 82.3627°W; 27 Aug. 2001; M. Hedin, M. Lowder, P. Paquin leg.; MCH 01_173; • 4♂, 7♀; Blue Ridge Parkway, Mile 370, 3 mi. SW Craggy Gardens turnoff; 35.6768°N, - 82.4322°W; 15 Aug. 1992; M. Hedin leg.; • 2♂, 8♀; Flat Creek at NE edge of Montreat; 35.6528°N, - 82.2972°W; 12 Aug. 1992; M. Hedin leg.; • 6♀; FR 63 along Mineral Creek , S of Dillingham; 35.7093°N, - 82.3939°W; 21 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg.; MCH 07_143; - North Carolina, Madison Co. • ♂, ♀; Anthodite Cave ; 5 Jan. 2002; J.D. Mayes leg.; • ♂, 4♀; FR 467 to Rich Mountain , 0.5 mi. to jnct w/ Hwy 25/70, W of Hurricane; 35.9274°N, - 82.7792°W; 22 Aug. 2007; M. Hedin, M. McCormack, S. Derkarabetian leg.; MCH 07_144; • 4♀, 1 imm; Rich Mountain , 0.5 mi. N Rich Mountain lookout; 35.9313°N, - 82.806°W; 19 Aug. 2001; M. Hedin, M. Lowder leg.; MCH 01_140; - North Carolina, Yancey Co. • 3♀, 2 imm; Blue Ridge Parkway at Balsam Gap, just down Big Butt trail; 35.7495°N, - 82.3343°W; 26 Aug. 2001; M. Hedin, M. Lowder, P. Paquin leg.; MCH 01_169; • 2♂, 3♀; Blue Ridge Parkway at Balsam Gap, just down Big Butt trail; 35.7495°N, - 82.3343°W; 5 Sep. 2002; M. Hedin, M. Lowder, P. Paquin leg.; MCH 02_195; - Tennessee, Cocke Co. • 5♀; along French Broad River , north of Wolf Creek Bridge , FR 209; 35.9228°N, - 82.9585°W; 12 Aug. 2004; M. Hedin, R. Keith, J. Starrett, S. Thomas leg.; MCH 04_044.

Diagnosis.

See Coyle and McGarity (1992) for diagnosis comparing Nesticus gertschi to other members of the species group; here revised to recognize the close relationship to N. canei sp. nov. Males can be distinguished from the latter by the tegular apophysis tip (beyond bend) broad and truncate (Fig. 39A, B ), and paracymbial distal process with subdistal processes. Females are very similar to N. secretus and N. canei sp. nov., with internal anterior plates of epigyna not projecting inwards and ventrally as strongly as in the latter species (Fig. 39C-F ).

Variation.

This species shows surprisingly little genitalic variation despite a relatively large geographic distribution (e.g., compare ♂ Fig. 39A, B . to Coyle and McGarity (1992) figs 15-17), and obvious lowland geographic barriers (Fig. 30 ). Specimens from surface-dwelling populations are generally smaller in body size than cave-dwelling specimens from the type locality. Two female specimens (of five total) from surface collections along the French Broad River (MCH 04_044) lack eye pigmentation, while cave-dwelling specimens from both Cedar Creek Cave and Anthodite Cave possess eye pigmentation.

Distribution and natural history.

Previously known only from the type locality (Cedar Creek Cave), this species is a fairly widespread surface-dwelling species (Fig. 30 ). The geographic distribution is apparently fragmented with northern, central, and southern populations, with all but one known population from east of the French Broad River (Anthodite Cave being the exception).

Surface collections are mostly from shaded boulderfields, with field notes suggesting spiders to be "fairly common" under rocks in void spaces. Montreat specimens were found in dark cracks and crevices of a man-made rock wall within 3 meters of a stream.

Remarks.

As discussed below, possibly synonymous with Nesticus secretus .

Strongly supported as a clade by UCE data, with nuclear subclades corresponding to northern vs. central + southern collection locations (Figs 3 , 4 ), separated by the Mars Hill lowland gap. Not recovered as monophyletic on the mitochondrial gene tree (Fig. 6 ), where sequences are intermixed with those of closely related Nesticus crosbyi and N. canei sp. nov.

Gertsch (1984, p. 30) cites a record for Nesticus reclusus as (" McDowell County, Montreat, 16 October, 1923, female "). However, our 1992 collections from Montreat (now in Buncombe County) only include N. gertschi , which is the locally prevalent species (Fig. 30 ). Also, members of the Nesticus reclusus group are not known from east of the Asheville Basin (Fig. 53 ). We have not seen the 1923 specimen but suspect either mislabeling or misidentification.

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 30. Distribution of Nesticus nasicus group species. Type localities designated with yellow circles. Primary cities shown for geographic context. Dashed lines circumscribe known species distributions; possible distribution of Nesticus secretus is tentative, see text for details.

Figure 39. Nesticus gertschi and N. secretus genitalia. N. gertschi A North Carolina, Yancey Co., Blue Ridge Parkway at Balsam Gap, MCH 02 _ 195, ♂ palp, ventral B North Carolina, Buncombe Co., NW of Hickory Nut Gap, Hwy 74, MCH 01 _ 173, ♂ palp, ventral. North Carolina, Buncombe Co., NW of Hickory Nut Gap, Hwy 74, MCH 01 _ 173, epigynum, ventral (C), dorsal (D). North Carolina, Yancey Co., Blue Ridge Parkway at Balsam Gap, MCH 02 _ 195, epigynum, ventral (E), dorsal (F). Scale bar: 0.5 mm. N. secretus Gertsch 1984 epigynum. Tennessee, Great Smoky Mountains National Park, ♀ holotype, ventral (G), dorsal (H).

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.