Nesticus binfordae, 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 binfordae sp. nov.

Figs 57A-C , 58A-F

Material examined.

Type material: Holotype: USA - Tennessee, Sevier Co. • ♂ holotype; Great Smoky Mountains NP, Greenbrier Cove, Middle Prong Little Pigeon River , 1.3 mi. upstream Greenbrier Picnic Area; 35.7042°N, - 83.3653°W; 20 Aug. 1992; M. Hedin leg; MCH specimen #1290 ; Paratypes: - Sevier Co. • ♀ paratype; data as for holotype; MCH specimen #1287; • 5♂, 14♀; data as for holotype; Non type material: - Cocke Co. • ♀; Great Smoky Mountains NP, N side Indian Camp Creek on Maddron Bald Trail ; 35.7378°N, - 83.2777°W; 16 Apr. 1994; M. Hedin, B. Dellinger leg.; • 2♀; Great Smoky Mountains NP, trail from Low Gap to Mt. Cammerer; 35.754°N, - 83.1658°W; 1 Aug. 2000; M. Hedin leg.; MCH 00_146 .

Diagnosis.

Most similar to close phylogenomic kin Nesticus dykemanae (Fig. 59A-C ) and N. jonesi (Fig. 56A ). Differing from the latter in having a sharp-tipped median apophysis, the shape of the basal tegular apophysis, and having a whip-like paradistal paracymbial process. Very similar to N. dykemanae , sharing the double-tipped median apophysis, but differing in the shape of the basal tegular apophysis and possessing a whip-like paradistal process. Sharing an almost identical epigynal morphology with N. jonesi .

Description of ♂ holotype

(MCH specimen #1290). Carapace dirty light orange, dusky lines leading from fovea to eye group. Legs colored as carapace, without markings. Abdomen background color as carapace, six pairs of lateral faint darker markings. All eyes approximately equal in size, except for AMEs, ~ 1/4 width of ALEs. Eyes with rings of dark pigment. CL 1.5, CW 1.3, abdomen length 1.7, total body length 3.2. Leg I total length 14.2 (3.9, 0.7, 4.35, 3.85, 1.4), leg formula 1423, leg I / CW ratio 10.9. Palp with broadly S-shaped tegular apophysis, distal part a short skinny curved blade with tapered tip, basal fork of apophysis a squat sclerotized spade with rounded edges (Fig. 57A-C ). Median apophysis anvil-shaped, both ends with sharp tips. Conductor tip bent, surrounded by small funnel-shaped cuticular sheath. Paracymbium with a skinny whip-like paradistal process, and distal process finger-like with slight serration along paradistal edge. Lacking a dorsomedial process. Distal part of ventral paracymbial process thickened, forming a small blade without cusps (Fig. 57A-C ).

♂ Variation.

Males are only known from the type locality and all match the holotype male, except for MCH specimen #1289 which lacks the paracymbial paradistal process (Fig. 57C ). Close examination of this specimen suggests that this process was broken off (process base is evident).

Description of ♀ paratype

(MCH specimen #1287). Carapace subdued burnt orange, distinct darker markings leading from fovea forward, dusky ring to edge of carapace. Legs light orange, with faint dusky dark markings. Abdomen slightly paler than carapace, with fused distal lateral dark markings. Posterior eyes approximately equal in size, ALE slightly smaller than PLEs, AMEs ~ 1/4 width of ALEs. Eyes with rings of dark pigment. CL 1.65, CW 1.4, abdomen length 2.35, total body length 4. Leg I total length 13.15 (3.75, 0.75, 4, 3.25, 1.4), leg formula 1423, leg I / CW ratio 9.4. Epigynum generally wider than tall, median septum relatively wide at top with adjacent heart-shaped lateral pockets (considering both sides). Septum narrows towards posterior end where lateral bars extend obliquely upwards, dark spermathecae lying beneath these bars and approximately following the upwards oblique path. Median septum extending past these bars and dipping inwards towards the abdomen. Viewed dorsally, dorsal internal plates lying slightly above sclerotization of the lateral pockets.

♀ Variation.

Females from different locations share a very similar epigynal morphology (Fig. 58A-F ).

Distribution and natural history.

Known only from three parallel north-flowing drainages in the Great Smoky Mountains National Park, including the Middle Prong of the Little Pigeon River, and more easterly draining Indian Camp and Cosby Creeks.

At the type locality in 1992 spiders were "very abundant in rock crevices, low to the ground, close to the river".

Along the Maddron Bald and Mt. Cammerer trails we collected both Nesticus cherokeensis and N. binfordae , indicating that these species are syntopic or nearly so at these locations. At both locations multiple collections were taken along an elevational transect and unfortunately lumped into a single collecting event, so it is not possible to discern if different species were collected at the exact same location (truly syntopic) or were closely parapatric along these elevational transects.

Etymology.

Named to honor Dr. Greta Binford. Friend, arachnologist, and Past President of the American Arachnological Society (AAS), here recognized for her inspirational spider research and her leadership in making the AAS a more diverse and welcoming society. We suspect that Dr. Binford would also greatly appreciate the beauty of the habitats that this spider calls home.

Remarks.

Part of a near phylogenomic trichotomy with Nesticus dykemanae and N. jonesi (Figs 3 , 4 ), with sCF values near a lower limit.

This species was called "N novsp2" (from site 48) in Hedin (1997b) and lumped with Nesticus dykemanae despite having distinctive (non-sister) ND1/16S sequences.

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 56. Nesticus jonesi genitalia A Alabama, Morgan Co., Cave Spring Cave, MCH specimen # 1644, ♂ palp, ventral. Alabama, Morgan Co., Cave Spring Cave, MCH specimen # 1656, epigynum, ventral (B), dorsal (C). Scale bar: 0.5 mm.

Figure 57. Nesticus binfordae sp. nov. ♂ palps. Tennessee, Sevier Co., Great Smoky Mountains NP, Middle Prong Little Pigeon River, MCH specimen # 1290, dorsal (A), ventral (B). Middle Prong Little Pigeon River, MCH specimen # 1289, dorsal (C). Scale bar: 0.5 mm.

Figure 58. Nesticus binfordae sp. nov. epigynal variation. Tennessee, Sevier Co., Great Smoky Mountains NP, Middle Prong Little Pigeon River, MCH specimen # 1283, ventral (A), dorsal (B). Tennessee, Cocke Co., Great Smoky Mountains NP, N side of Indian Camp Creek, MCH specimen # 1981, ventral (C), dorsal (D). Tennessee, Cocke Co., Great Smoky Mountains NP, trail from Low Gap to Mt. Cammerer, MCH 00 _ 146, ventral (E), dorsal (F). Scale bar: 0.5 mm.

Figure 59. Nesticus dykemanae sp. nov. genitalia. ♂ palps - Tennessee, Sevier Co., Great Smoky Mountains NP, Hwy 441 near Chimney Tops trailhead, MCH 00 _ 143 (SDSU _ TAC 000673), ♂ palp ventral (A), dorsal (B) C Tennessee, Sevier Co., Great Smoky Mountains NP, Hwy 441, between tunnel and Chimney picnic area, MCH specimen # 1977, ♂ palp ventral. Scale bar: 0.5 mm. epigynal variation - Tennessee, Sevier Co., Great Smoky Mountains NP, Hwy 441 near Chimney Tops trailhead, MCH 00 _ 143 (SDSU _ TAC 000674), epigynum ventral (D), dorsal (E). Tennessee, Sevier Co., Great Smoky Mountains NP, Hwy 441, between tunnel and Chimney picnic area, MCH specimen # 1973, epigynum ventral (F), dorsal (G). Tennessee, Sevier Co., Great Smoky Mountains NP, Hwy 441, N of Chimneys campground, epigynum ventral (H), dorsal (I). Scale bar: 0.5 mm.