Nesticus dellingeri, 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 dellingeri sp. nov.

Fig. 55A-G

Material examined.

Type material: Holotype: USA - North Carolina, Macon Co. • holotype ♂; vicinity Whiteside Mountain, off Hwy 64, SW of Cashiers; 35.0793°N, - 83.1415°W; 8 Aug. 1992; M. Hedin, I.-M. Tso leg.; MCH specimen #1047 ; Paratypes: - North Carolina, Macon Co. • 5♂, 9♀; vic Whiteside Mountain, off Hwy 64, SW of Cashiers; 35.0793°N, - 83.1415°W; 8 Aug. 1992; M. Hedin, I.-M. Tso leg. ; Non type material : - North Carolina, Jackson Co. • 2♀; along Chattooga River, NE side near mouth Scotsman Creek ; 35.013°N, - 83.1123°W; 16 Aug. 1991; B. Dellinger leg. ; • ♂; along Chattooga River, NE side, 0.2 mi. W mouth Scotsman Creek ; 35.0136°N, - 83.1135°W; 17 Aug. 1991; B. Dellinger leg. ; • ♂, 5♀; Whitewater River, below Upper Falls ; 35.0337°N, - 83.0141°W; 2 Sep. 2002; M. Hedin, F. Coyle, M. Lowder, P. Paquin leg. ; MCH 02_183; - North Carolina, Macon Co. • ♂, 5♀, 5 imm; Chattooga River, vic BullPen bridge crossing; 35.0172°N, - 83.1262°W; 2 Sep. 2002; M. Hedin, M. Lowder, P. Paquin leg. ; MCH 02_180; • 7♀; Chattooga River, vic BullPen bridge crossing, SE of Highlands; 35.0172°N, - 83.1262°W; 8 Aug. 1992; M. Hedin leg. ; - South Carolina, Oconee Co. • ♂, 3♀; along Whitewater River , just S NC/SC stateline; 35.0271°N, - 83.0094°W; 13 Apr. 1992; B. Dellinger leg.

Diagnosis.

Sister to other members of a phylogenomic subclade including Nesticus binfordae , N. dykemanae and N. jonesi , and morphologically most similar to these geographically disjunct taxa (in particular, sharing the spade-like basal tegular apophysis; Fig. 52 ). Males of N. dellingeri differ from males of these other taxa in the shape of the distal tegular apophysis (broad vs. skinny), the shape of the median apophysis, the shape of the paracymbial distal process, and in details of the paracymbial ventral process cusps. This species shares a very similar epigynal morphology with other members of the subclade (see descriptions below).

Description of ♂ holotype

(MCH specimen #1047). Carapace dusky cream to orange, with faint dark pigment behind ocular area and along carapace margin. Legs approximately concolorous pale. Abdomen with paired, lateral darker markings on dirty gray background. All eyes approximately equal in size, AMEs barely visible. Eyes with light rings of dark pigment. CL 1.4, CW 1.1, abdomen length 2, total body length 3.4. Leg I total length 9.9 (2.75, 0.6, 3, 2.5, 1.05), leg formula 1423, leg I / CW ratio 9.0. Palp with broadly S-shaped tegular apophysis, distal part a short, curved blade with acute tip, basal fork of apophysis a short, square sclerotized spade (Fig. 55A-C ). Median apophysis anvil-shaped, distal end a sharp tip. Conductor tip bent, surrounded by small funnel-shaped cuticular sheath. Paracymbium lacking a paradistal process, distal process finger-like with slight serration along paradistal edge. Lacking a dorsomedial process. Distal part of ventral paracymbial process thickened, with small cusps.

♂ Variation.

Males from four non-type localities match topotypic males very closely (Fig. 55A-C ).

Description of ♀ paratype

(MCH specimen #1057). Carapace color as in male, slightly darker orange. Legs approximately concolorous pale. Abdomen with paired, lateral darker maculations on dirty gray background. All eyes approximately equal in size, AMEs miniscule but visible. Eyes with rings of dark pigment. CL 1.2, CW 1.1, abdomen length 1.65, total body length 2.85. Leg I total 7.3 (2.1, 0.55, 2.05, 1.7, 0.9), leg formula 1423, leg I / CW ratio 6.6. Epigynum generally wider than tall, median septum relatively wide with directly adjacent lateral pockets (Fig. 55D-G ). Posterior end of septum with lateral bars oriented obliquely upwards, dark spermathecae lying beneath these bars and approximately following the upwards oblique path. Median septum narrowing past these bars and projecting inwards towards the abdomen. Viewed dorsally, dorsal internal pockets lying slightly above sclerotization of the lateral pockets.

♀ Variation.

Females from different locations share a very similar epigynal morphology (Fig. 55D-G ).

Distribution and natural history.

Known only from a very small area in the upper Chattooga River and upper Whitewater River drainages (Fig. 53 ), along the south face of the Blue Ridge Escarpment in the North and South Carolina borderlands. Except for the type locality, most collections are relatively small in total animals collected, suggesting a natural rarity for this species. At the type locality (Whiteside Mountain) a total of 14 adults and 8 immature specimens was collected from a crevice cave at the base of rocky cliffs.

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

Etymology.

This species is named to recognize and honor Bob Dellinger, a special naturalist from western North Carolina. Bob’s knowledge of the flora and fauna of southern Appalachia is remarkable, and he personally collected or helped to collect (with first author MH) many Nesticus from this region.

Remarks.

Nesticus dellingeri is geographically disjunct from phylogenetic relatives N. binfordae , N. dykemanae and N. jonesi (Fig. 53 ). The regions separating these taxa have been extensively sampled for Nesticus and are occupied by species from other species groups ( N. nasicus , Nesticus tennesseensis group members), or more distant Nesticus reclusus group members.

Figures

Figure 52. Comparative ♂ morphology of Nesticus reclusus group species A Nesticus sheari B N. dellingeri C N. jonesi D N. binfordae E N. dykemanae F N. bishopi G N. stupkai H N. reclusus. All views ventral. See subsequent figures for specimen locations and voucher details.

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 55. Nesticus dellingeri sp. nov. genitalia. North Carolina, Macon Co., vicinity Whiteside Mountain, MCH specimen # 1047, ♂ palp, dorsal (A), ventral (B) C North Carolina, Jackson Co., Whitewater River, below Upper Falls, MCH 02 _ 183, palp, ventral. North Carolina, Macon Co., vicinity Whiteside Mountain, MCH specimen # 1057, epigynum, ventral (D), dorsal (E). North Carolina, Jackson Co., Whitewater River, below Upper Falls, MCH 02 _ 183, ventral (F), dorsal (G). Scale bar: 0.5 mm.