Nesticus mimus 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 mimus Gertsch, 1984

Figs 19A-C , 20A-H

Nesticus mimus Gertsch, 1984: 26, figs 64, 65.

Nesticus tennesseensis Gertsch, 1984: 24, 25 (in part).

Material examined.

Type material: Holotype: USA - Virginia, Washington Co. • ♂ holotype; Shiloh School Cave, SE of Abingdon; 25 Nov. 1960; C.W. Greever leg; AMNH. Non type material: USA - Tennessee, Johnson Co. • ♂, 3♀; Backbone Rock Rec Area , 4 mi. S Damascus, off Hwy 133; 36.594°N, - 81.8163°W; 7 Aug. 2004; M. Hedin, R. Keith, J. Starrett, S. Thomas leg.; MCH 04_025; Tennessee, Sullivan Co. • ♂, ♀; Potter's Cave, S Abingdon ; 14 Jul. 1979; J.R. Holsinger et al. leg.; AMNH; - Virginia, Giles Co. • 2♀, 26 imm; Curve Saltpetre Cave ; 14 May. 2019; T. Malabad leg.; • ♀; Harris Cave , S of Pearisburg; 29 Jun. 1974; J. Holsinger, L. Ferguson leg; AMNH; • ♀, 2 imm; Harris Cave ; 14 Sep. 2018; T. Malabad leg.; • 3♀, 7 imm; Spruce Run Mountain Cave ; 14 Nov. 2018; T. Malabad leg.; • 2 imm; Straley's Cave No. 1; 6 Sep. 1958; T.C. Barr leg; AMNH; • 2♂, 3♀; Co. Straley's Cave No. 1 off Eggleston Road, S Pembroke; 17 Sep. 1992; M. Hedin, S. O’Kane leg.; • ♂, 7♀; Straley's Cave No. 1 off Eggleston Road, S Pembroke; 10 Oct. 1993; M. Hedin, C. Phillips leg.; • ♀; Straleys Cave No. 2; 12 Sep. 2018; T. Malabad leg.; - Pulaski Co. • 4♀, 31 imm; Maze Cave ; 25 Sep. 2018; T. Malabad leg.; • 2♀; Mebane Saltpetre Cave ; 3 Oct. 2018; T. Malabad leg.; - Radford Co. • ♀, 3 imm; Adams Cave ; 11 Apr. 2019; T. Malabad leg.; - Smyth Co. • 3♂, 6♀; Cow Shelter Cave , SE of Sugar Grove; 6 Oct. 1993; M. Hedin, C. Phillips leg.; • ♂, ♀; McMullin Cave , southwest of Marion , VA; 11 Jul. 2019; T. Malabad leg.; • ♀; McMullin Cave ; 10 Sep. 2019; T. Malabad, K. Kosič Ficco leg.; • 2♀; McMullin Cave ; 22 Oct. 2019; T. Malabad, K. Kosič Ficco leg.; • 9♂, 20♀; McMullin Cave ; 2 Mar. 2020; T. Malabad, K. Kosič Ficco leg.; • ♂, 3♀; McMullin Cave ; 23 Jun. 2020; T. Malabad, A. Malabad leg.; • 3♀; Mt. Rogers National Rec Area , 0.5 mi S of Hurricane CG on NF 84; 36.7186°N, - 81.4911°W; 11 Aug. 2007; M. Hedin, R. Keith leg.; MCH 07_087; • ♀, 3 imm; Rowland Creek Cave ; 10 Aug. 2018; T. Malabad leg.; • 8♂, 7♀, 1 imm; Whitetop Laurel Creek , Hwy 58, E of Damascus; 36.637°N, - 81.75°W; 31 May. 2016; M. Hedin, S. Derkarabetian, J. Starrett, D. Proud leg.; MCH 16_034; - Washington Co. • 7♂, 9♀; Neal’s Sinks, 1.5 mi S Alvarado, Sweet Hollow Road ; 18 Sep. 1992; M. Hedin, S. O’Kane leg.; - Wythe Co. • ♂, 4♀, 12 imm; Canyon Cave No. 1; 21 Sep. 2018; T. Malabad leg.; • ♂, ♀, 1 imm; Deep Spring Cave ; 21 Sep. 2018; W. Orndorff leg.; • 6 imm; Deep Spring Cave ; 7 Jul. 2018; T. Malabad leg.; • 2♂, 2♀, 14 imm; Mockleys Cave ; 20 Sep. 2018; T. Malabad leg.; • ♂, ♀, 4 imm; Sinking Spring Cave No. 1; 21 Sep. 2018; T. Malabad leg.; • ♀, 7 imm; Sinking Spring Cave No. 2; 21 Sep. 2018; T. Malabad leg.; • 2♀, 6 imm; Speedwell Cave No. 1; 20 Sep. 2018; T. Malabad leg.

Diagnosis.

Strongly supported by both mitochondrial and UCE data as sister to Nesticus holsingeri . In N. mimus the basal dorsal process of the paracymbium is longer (Fig. 19A, B ) and the tegular apophysis is relatively long and narrow, almost reaching the pronounced acute distal process of the median apophysis (Fig. 19B, C ). Females possess a relatively elongate, narrow epigynum that is distinctive in the species group in possessing long, thin spermathecae that viewed ventrally bow upwards around the outer edge of the lateral pockets (Fig. 20A-H ).

Description of previously undescribed ♀

(MCH specimen #1398). Carapace light cream colored, faint gray pigmentation behind ocular area leading to midline. Legs pale yellow / cream. Abdomen concolorous light cream. All eyes approximately equal in size, except for AMEs, ~ 1/4 width of ALEs. Eyes with rings of dark pigment. CL 1.37, CW 1.19, abdomen length 1.89, total body length 3.26. Leg I total length 8.68 (2.36, 0.58, 2.5, 2.22, 1.02), leg formula 1423, leg I / CW ratio 7.3. Epigynum relatively elongate and narrow. Lateral lobes well-defined with internal edges that extend posteriorly to the end of median septum or slightly further. Spermathecae extremely long and curved around fovea to anterior edge of epigynum. Large internal lobes (viewed dorsally) extend anteriorly with sclerotized rims. Medial margins parallel to each other but not touching along midline.

Variation.

No noteworthy variation in male or female genitalia was found across sample locations.

Distribution and natural history.

Known only from a small area of the Appalachian Valley and Ridge in southwestern Virginia and adjacent eastern Tennessee (Fig. 13 ). Found in both caves and moist, dark near-surface microhabitats. As an example of the near-surface natural history, eight males and seven females were collected along Whitetop Laurel Creek (MCH 16_034) from rock piles in a rich, rocky streamside forest.

Remarks.

Gertsch (1984) incorrectly identified specimens from the following locations as Nesticus tennesseensis : Straley’s Cave No. 1 (2 immatures), Harris Cave (1 ♀), and Potter’s Cave (1 ♂, 1 ♀) - specimens from these populations belong to N. mimus . Gertsch (1984) also provisionally identified specimens from two montane locations as N. mimus : a single female from Table Rock Mountain (Burke County, NC), and a male specimen from Grandfather Mountain (cited as Watauga County, NC but label reads Avery County, NC). We contend that specimens from both locations correspond to N. carolinensis (see further comments below).

Specimens from Hedin (1997b) referred to as Nesticus "nov sp 1" (from Neal’s Sinks, Straley’s Cave No. 1, and Cow Shelter Cave) are actually N. mimus , and those referred to as N. mimus (Grandfather Mtn, Linville Gorge) are actually N. carolinensis .

Figures

Figure 13. Distribution of Nesticus tennesseensis group species. Type localities designated with yellow circles. State boundaries and major cities shown for geographic context. Dashed lines circumscribe known species distributions.

Figure 19. Nesticus mimus ♂ palps. Virginia, Giles Co., Straley's Cave # 1, MCH specimen # 1396, dorsal (A), ventral (B) C Tennessee, Johnson Co., Backbone Rock Recreational Area, MCH 04 _ 025, ventral. Scale bar: 0.5 mm.

Figure 20. Nesticus mimus epigynal variation. Virginia, Giles Co., Straley's Cave # 1, MCH specimen # 1399, ventral (A), dorsal (B). Virginia, Washington Co., Neal's Sinks, MCH specimen # 1430, ventral (C), dorsal (D). Virginia, Smyth Co., near Hurricane CG, MCH 07 _ 087, ventral (E), dorsal (F). Tennessee, Johnson Co., Backbone Rock Recreational Area, MCH 04 _ 025, ventral (G), dorsal (H). Scale bar: 0.5 mm.