Pholcus chugok Lee & Lee, sp. nov.

Figs 1A–B, 2A–B, 3, 12, 17A–C, 18

Type material. Holotype: 1♂, SOUTH KOREA: Gangwon-do: Chuncheon-si, Buksan-myeon, Chugok-ri (38˚02'22"N, 127˚53'12"E, 293 m), 23 Jun. 2021, Sam-Kyu Kim leg. (NIBR) . Paratypes: 1♀, same data as for holotype (KNU-Ar 20230032); 3♂♂, same data as for holotype (KNU-Ar 20230033–5); 4♀♀, same data as for holotype (KNU-Ar 20230036–9); 2♂♂ 12♀♀, same data as for holotype (KNU-Ar 20230040) .

Other material examined. 12♂♂ 4♀♀, Chuncheon-si, Sinbuk-eup, a small cave in Baehuryeong (37˚58'59"N, 127˚47'19"E, 537 m), 15 Feb. 2023, Jun-Gi Lee et al. leg. (KNU) ; 3♂♂ 1♀, same locality, 4 Apr. 2023, same collector (KNU); 1♀, same locality, 3 May 2023, same collector (KNU); 3♂♂ 2♀♀, same locality, 7 Jun. 2023, same collector (KNU); 3♂♂ 7♀♀, Hwacheon-gun, Gandong-myeon, Bangcheon-ri (38˚03'47"N, 127˚50'59"E, 455 m), 23 Jun. 2021, Sam-Kyu Kim leg. (KNU) ; 1♂ 4♀♀, Yanggu-gun, Yanggu-eup, Mt. Samyeongsan (38˚04'07"N, 127˚55'50"E, 468 m), 23 Jun. 2021, Sam-Kyu Kim leg. (KNU) .

Etymology. The specific epithet is derived from the type locality, Chugok-ri. Noun in apposition.

Diagnosis. Males similar to Pholcus chuncheonensis Lee, Choi & Kim, 2021 and Pholcus pajuensis Lee, Choi & Kim, 2021, having wide prolateral process of procursus with sharp branches (Fig. 3D) and auriculate uncus (Fig. 3F), but can be distinguished by: 1) prolateral process of procursus tip distally with single triangular branch on inner margin, several teeth on outer margin, inner branch distinctly large (Fig. 3D) (with single triangular inner branch and outer several teeth both positioned on outer margin, inner one slightly large in P. chuncheonensis, see Lee et al. 2021b: fig. 3C; with two triangular branch in P. pajuensis, see Lee et al. 2021b: fig. 5C); 2) uncus distally hooked and pointed (Fig. 3F) (distally blunt in P. chuncheonensis, see Lee et al. 2021b: fig. 3D); 3) pseudoappendix distally bent nearly perpendicularly and pointed (Fig. 3F) (distally spatulate in P. chuncheonensis, see Lee et al. 2021b: fig. 3D; distally slightly sinuated and pointed tip in P. pajuensis, see Lee et al. 2021b: fig. 5D). Females similar to P. pajuensis having emarginated anterior arch and posterolateral wrinkled structure of internal genitalia (Fig. 3I), but can be distinguished by: 1) posterolateral edge of epigynal posterior plate almost straight (Fig. 3H) (slightly elongated in P. pajuensis, see Lee et al. 2021b: fig. 6A); 2) posterior wrinkled structure of internal genitalia widely transverse (Fig. 3I) (flower-bud like, positioned laterally in P. pajuensis, see Lee et al. 2021b: fig. 6B).

Description. Male (holotype). Habitus as in Fig. 1A. Total length 5.6. Prosoma 1.5 long, 1.7 wide. Carapace round, pale yellow, thoracic area with dark brown radial marks and marginal band. Eye area slightly elevated, posteriorly with dark brown marks laterally and medially. Diameter of AME 103 µm, ALE 184 µm, PME 144 µm, PLE 160 µm. AME–AME 58 µm, PME–PME 233 µm, PME–ALE 50 µm. Clypeus with large brown mark, without process. Chelicera (Fig. 2A–B) with blunt conical proximo-lateral apophysis with small hump proximoentally, small and ventrally curved frontal apophysis, and ventrally curved, notched triangular distal apophysis as long as proximo-lateral apophysis. Sternum longer than wide, shield-like, pale yellow with brown marks laterally and posteriorly. Opisthosoma 3.8 long, 1.7 wide, cylindrical, pale yellow, without cuticular pattern, with cardiac pattern and many black granular spots dorsally and laterally. Leg femora and tibiae yellowish brown with two whitish and two dark brown bands distally, two dark brown bands proximally; patellae, metatarsi, tarsi dark brown, without bands; leg Ⅰ femur distinctly darker. Leg Ⅰ 46.2 (11.9 + 0.7 + 11.9 + 19.4 + 2.3), leg II 30.9 (8.7 + 0.7 + 7.8 + 12.3 + 1.5), leg III 20.4 (6.0 + 0.6 + 5.0 + 7.7 + 1.2), leg IV 28.1 (8.2 + 0.7 + 7.0 + 10.8 + 1.5). Ratio of leg Ⅰ (17.0: 1.0: 17.0: 27.7: 3.2), leg II (12.2: 1.0: 10.9: 17.3: 2.1), leg III (9.8: 1.0: 8.1: 12.7: 1.9), leg IV (12.6: 1.0: 10.7: 16.6: 2.2). Leg formula 1243. Tibia Ⅰ L/d 66. Tibiae, metatarsi, tarsi with short vertical setae, tibiae and metatarsi Ⅰ, II with long curved hairs. Tibiae with three trichobothria, except tibia Ⅰ (prolaterally absent). Retrolateral trichobothrium on tibia Ⅰ at 6% proximally. Tarsus I with 27 pseudosegments, mostly irregular. Palp (Fig. 3A–G). Trochanter apophysis (Fig. 3B) shorter than half of femur length, straight, slender, distally blunt with single curved hair, proximo-retrolaterally with tubercle; femur ventrally swollen; tibia with prolatero-ventral tubercle; procursus (Fig. 3A–B) dark brown, slightly sinuated dorsally, with small ventral knee; dorso-subdistally swollen, with single spine near retrolateral ridges (Fig. 3C); procursus tip (Fig. 3C–E) with two long and two short ridges retrolaterally (Fig. 3E), wide prolateral process with two plates [dorsal plate quadrate, weakly sclerotized, distal margin strongly sclerotized with outer four small teeth (arrowed 1 in Fig. 3D) and inner single large triangular projection (arrowed 2 in Fig. 3D), ventral plate membranous (arrowed in Fig. 3C)], and blunt triangular ventral process (arrowed 3 in Fig. 3D); genital bulb (Fig. 3A) oval, pale yellow; uncus (Fig. 3A, F–G) about 0.7 times as long as genital bulb, dark brown, auriculate, distally pointed and hooked, proximo-ectal margin with numerous tiny scales; pseudoappendix (Fig. 3F–G) dark brown, about half as long as uncus, thin, distally pointed and curved perpendicularly; embolus (Fig. 3F–G) slender, distally fringed, weakly sclerotized, slightly longer than uncus.

Female (one of paratypes, KNU-Ar 20230032). Habitus as in Fig. 1B. Somatic characteristics generally similar to male, but cheliceral apophyses absent, legs slightly shorter. Total length 6.0. Prosoma 1.6 long, 1.8 wide. Diameter of AME 92 µm, ALE 158 µm, PME 133 µm, PLE 148 µm. AME–AME 58 µm, PME–PME 221 µm, PME–ALE 57 µm. Opisthosoma 3.9 long, 2.1 wide. Leg Ⅰ 36.1 (9.0 + 0.7 + 9.3 + 14.8 + 2.3), leg II 24.9 (6.8 + 0.6 + 6.4 + 9.7 + 1.5), leg III 18.1 (5.4 + 0.6 + 4.3 + 6.7 + 1.2), leg IV 24.9 (7.1 + 0.6 + 6.3 + 9.4 + 1.4). Ratio of leg Ⅰ (12.5: 1.0: 12.9: 20.6: 3.2), leg II (12.3: 1.0: 11.5: 12.0: 2.1), leg III (9.6: 1.0: 7.7: 12.0: 2.1), leg IV (11.7: 1.0: 10.3: 15.4: 2.3). Leg formula 1243. Tibia I L/d 46. Epigyne (Fig. 3H). Anterior plate triangular, yellowish brown; posterior plate bright ivory, slightly shorter than anterior plate, posterior edge almost straight, with pair of gradually brightened sclerotized areas running from posterolaterally to mediolaterally; epigynal knob dark brown, tiny, blunt, about 0.2 times as long as posterior plate; posterior sclerotized cuticle yellowish brown, slightly procurved, half as long as posterior plate; interspace between posterior plate and posterior sclerotized cuticle slightly shorter than posterior plate, with indistinct yellowish brown mark medially. Internal genitalia (Fig. 3I). Anterior arch wide and emarginated, medially with triangular strongly sclerotized area; genital valve slightly curved, hidden by anterior arch dorsally; lateral portion with complex wavy wrinkled transverse structure; pore plates ovoid, close together, anterior half covering triangular sclerotized area of anterior arch.

Variation. Males. Prosoma width: 1.6–1.8 (mean 1.7), tibia Ⅰ: 8.8–13.3 (mean 11.4) (n=10).

An intrapopulational variation was observed on the number and the arrangement of teeth on the outer distal margin of prolateral process in procursus tip (Fig. 12A–F). Even the asymmetry in this structure was found in some individuals (Fig. 12A).

Females. Prosoma width: 1.5–1.8 (mean 1.6), tibia Ⅰ: 7.8–9.3 (mean 8.3) (n=10). An intrapopulational variation was observed on the shape and size of pore plates, and the shape of the margin of anterior arch and the posterolateral wrinkled structures of internal genitalia (Fig. 12L–P), but the epigynal shapes were largely consistent (Fig. 12G– K).

Habitat information. This species was found on rock walls and crevices under rocks in streamside of mountainous regions and inside caves near the entrance (Fig. 17A–C).

Distribution. Korea (Chuncheon, Hwacheon, Yanggu) (Fig. 18).