1. INTRODUCTION

Pholcidae C. L. Koch, 1850 is one of the most diverse and largest families comprising 1,982 species in 97 genera within the order Araneae Clerck, 1757 (World Spider Catalog 2024). The genus Pholcus Walckenaer, 1805 is one of the largest genera in the family are known to occur mainly on dusky, humid spaces like rock walls and road drains in mountainous regions (Lee et al. 2021a;Yao et al. 2021). Although many researches on the genus Pholcus, especially on the P. phungiformesgroup have been reported recently in Korea (Seo 2018;Lee et al. 2021a, 2021b;Jang et al. 2023a, 2023b;Lee et al. 2024), there are still many species of this genus to be explored in Korea as the geographically widespread mountainous forests and rock walls of the Korean Peninsula provide abundant suitable habitats for Pholcus spiders. Two new spiders belonging to P. phungiformes- group were collected during a seasonal survey on the spider fauna of mountainous mixed forest valleys in 2023. This work provides diagnoses, detailed descriptions, and taxonomic photographs for these new species.

2. MATERIALS AND METHODS

All specimens were collected by hands and preserved in 98% ethyl alcohol and external morphology was examined under a Leica S8APO stereomicroscope (Singapore). Images were captured with a Dhyana 400DC zoom digital camera (China) mounted on a Leica S8APO and assembled using Helicon Focus 8.2.0 image stacking software (Khmelik et al. 2006). Measurements of body parts were made with an ocular micrometer and are recorded in millimeters. Internal genitalia of females were removed and treated in 10% KOH solu-tion for two hours before illustration. Leg measurements are shown as: total length (femur, patella, tibia, metatarsus, tarsus). Morphological terminology follows Huber (2011). The examined specimens including type materials are deposited in the Nakdonggang National Institute of Biological Resources in Sangju (NNIBR), and Konkuk University in Seoul (KKU), Korea. The following abbreviations are used in the descriptions: ALE=anterior lateral eye, AME=anterior median eye, PLE=posterior lateral eye; PME=posterior median eye, ALE-AME=distance between ALEAME, ALE-PLE=distance between ALE-PLE, AMEAME= distance between AMEs, AME-PME=distance between AME-PME, PLE-PME=distance between PLE-PME, PME-PME=distance between PMEs in the eye region; L/d=length/diameter in the leg measurement.

3. TAXONOMY

Family Pholcidae C. L. Koch, 1850

Subfamily Pholcinae C.L. Koch, 1850

Genus Pholcus Walckenaer, 1805

Diagnosis and detail description. See Huber (2011).

Type species. Aranea phalangioides Fuesslin, 1775.

Pholcus phungiformes species-group

Diagnosis and description. See Huber (2011) and Yao et al. (2021).

Pholcus muju sp. nov.

무주유령거미 (신칭) (Fig. 1)

Type materials. Holotype: ♂ (NNIBR, #NNIBRIV 122441), Mt. Deogyusan, Samgong-ri, Seolcheonmyeon, Muju-gun, Jeonbuk-do, Korea (35.885876N, 127.777321E, alt. 670 m), 18 September 2023, C.M. Jang & S.T. Kim leg. Paratypes: 2♂♂, 3♀♀ (1♀: NNIBR, #NNIBRIV122440, 2♂♂, 2♀♀: KKU, #Ara_ Phol_Pholcus muju_20230918_01-04), same data as the holotype.

Etymology. The specific name is a noun in apposition referred to the type locality, Muju-gun, Jeonbuk-do. Diagnosis.Pholcus muju sp. nov. is similar to P. piagolensisSeo, 2018 but can be distinguished from the latter by the combination of the following characteristics: Males - uncus rectangular and strongly serrated distally (Fig. 2H) versus uncus potato-shaped with and slightly serrated distally (Seo 2018: 252, f. 2H). Females - posterior epigynal plate strongly depressed medially (Fig. 1E) versus posterior epigynal plate slightlly depressed medially, knob rather long and slender (Fig. 1E) versus knob short and thick, pore plates elliptical and adjacent to the anterior arch (Fig. 1G) versus pore plates triangular and separated from the anterior arch (Seo 2018: 252, f. 2K, L).

Description. Male (holotype). Habitus as in Fig. 1A. Total length 5.93. Carapace: 1.86 long/1.77 wide. Eyes: AER 0.68, PER 0.74, ALE 0.18, AME 0.11, PLE 0.17, PME 0.16, ALE-AME 0.05, ALE-PLE contiguous, AME-AME 0.07, AME-PME 0.06, PLE-PME 0.04, PME-PME 0.25. Chelicera: 0.90 long/0.29 wide. Endite: 0.44 long/0.25 wide. Labium: 0.22 long/0.37 wide. Sternum: 0.88 long/1.12 wide. Legs: I 46.09 (11.20, 0.74, 11.97, 19.77, 2.41), II 30.97 (8.63, 0.71, 7.80, 12.36, 1.47), III 21.46 (6.27, 0.64, 5.29, 8.08, 1.18), IV 28.26 (8.30, 0.63, 7.09, 10.87, 1.37), tibia I L/d 61. Palp: 4.00 (0.83, 0.37, 1.26, - , 1.54). Abdomen: 3.82 long/2.30 wide.

Carapace pale yellowish brown, head region with pale blackish brown median and marginal bands, thoracic region with pale blackish brown radial and marginal bands (Fig. 1A). Chelicera with three apophyses; blunt proximo-lateral apophysis diagonally upward and protruding out of chelicera, rather long and pointed frontal apophysis protruding forward, and thick and pointed distal apophysis diagonally downward (Fig. 1C, D). Legs yellowish brown, retrolateral trichobothrium on tibia I at 5% proximally, tarsus I with 40> indistinct and irregular pseudosegments except 10 distally, femora and tibia with two proximal annuli and two distal annuli, metatarsi with one proximal anulus and one distal annulus, leg formula I-II-IV-III. Abdomen elliptical, pale reddish yellow with a long cardiac pattern and many black irregular spots (Fig. 1A). Palp (Fig. 1H-J): trochanter short and bulged, shorter than femur; palpal tibia with oblong prolatero-ventral modification (Fig. 1H); bulb pale yellowish brown, cordiform, appendix absent (Fig. 1H, K); uncus dark blackish brown and rectangular, strongly serrated distally pseudoappendix absent (Fig. 1H, K); embolus unmodified, weakly sclerotized with some semi-transparent distal fringed processes (Fig. 1H, K); procursus large and brown with dark blackish brown margin, distinct ventral knee present, two distal apophyses present, retrolatero-distal apophysis blunt with membranous tip (numbered 1 in Fig. 1H-J), prolateral apophysis branched with pointed and claw-shaped tips (numbered 2 in Fig. 1H-J).

Female. General appearance similar to male, habitus as in Fig. 1B. Total length 5.08. Carapace: 1.54 long/1.55 wide. Eyes: AER 0.57, PER 0.62, ALE 0.17, AME 0.09, PLE 0.16, PME 0.14, ALE-AME 0.04, ALE-PLE contiguous, AME-AME 0.05, AME-PME 0.07, PLE-PME 0.04, PME-PME 0.20. Chelicera: 0.72 long/0.25 wide. Endite: 0.41 long/0.25 wide. Labium: 0.27 long/0.32 wide. Sternum: 0.73 long/0.97 wide. Legs: I 28.84 (7.04, 0.60, 7.36, 11.86, 1.98), II 19.75 (5.32, 0.60, 4.91, 7.57, 1.35), III 14.65 (4.16, 0.51, 3.60, 5.36, 1.02), IV 19.33 (5.55, 0.51, 4.99, 7.14, 1.14), tibia I L/d 39. Palp: 1.16 (0.36, 0.16, 0.21, - , 0.43). Abdomen: 3.36 long/2.21 wide. Epigynum: 1.05 wide.

Epigynum (Fig. 1E, F): circular, slightly longer than wide, anterior epigynal plate sclerotized with one pair of semicircular processes laterally, posterior epigynal plate strongly depressed medially, anterior epigynal plate and posterior epigynal plate contiguous, both epigynal plates strongly protruding, knob rather long and slender with a blunt tip. Internal genitalia (Fig. 1G): anterior arch slightly recurved, pore plates elliptical and narrow anteromedially, adjacent to the anterior arch, moderately separated from each other.

Variation. Tibia I in three males (Holotype and paratypes): 11.86, 11.97, 12.01 (11.95±0.08). Tibia I in three females (Paratypes): 6.73, 7.33, 7.11 (7.06±0.30).

Habitat. The species was collected by hand on rock walls and under rocks in mountainous mixed forest valley.

Distribution. Korea (Muju-gun, Jeonbuk-do).

Pholcus yeongheung sp. nov.

영흥유령거미 (신칭) (Fig. 2)

Etymology. The specific name is a noun in apposition referred to the type locality, Yeongheung-ri, Yeongweol- gun, Gangwon-do.

Diagnosis.Pholcus yeongheung sp. nov. is similar to Pholcus joreongensisSeo, 2004 in males and Pholcus yeongwol Huber, 2011 in females, but can be distinguished from the latter by the combination of the following characteristics: Males - trochanter long and straight (Fig. 2H, J) versus trochanter long and curved, procursus without dorso-distal apophysis (Fig. 2H, J) versus procursus with dorso-distal apophysis, ventro-distal apophysis with bifurcate and pointed tips (Fig. 2H-J) versus ventro-distal apophysis with pointed tip (Seo 2004: 74, f. 1A). Females - anterior epigynal plate with one pair of triangular processes (Fig. 2E) versus anterior epigynal plate with one pair of semicircular processes (Huber 2011: 479, f. 2138-2140, 2278, 2279). Although a diagnosis was provided, the genital organs of the female of the new species were very similar to that of P. yeongwol. We were unable to collect specimens of P. yeongwol, so we could not make actual comparisons between specimens. However, we collected many spiders corresponding to the new species, excluding the types, from the type locality, but could not find any sympatric species. Additionally, the genital structures of all male and female specimens were consistent, leading us to conclude that this species is new.

Type materials. Holotype: ♂ (NNIBR, #NNIBRIV122 439), Yeongheung-ri, Yeongwol-eup, Yeongweol-gun, Gangwon-do, Korea (37.206306N, 128.474806E, alt. 290 m), 8 September 2023, C.M. Jang & S.T. Kim leg. Paratypes: 2♂♂, 3♀♀ (1♀: NNIBR, #NNIBRIV122 438, 2♂♂, 2♀♀: KKU, #Ara_Phol_Pholcus yeongheung_ 20230908_01-04), same data as the holotype. Description. Male (holotype). Habitus as in Fig. 2A. Total length 5.98. Carapace: 1.78 long/1.73 wide. Eyes: AER 0.67, PER 0.72, ALE 0.17, AME 0.13, PLE 0.16, PME 0.15, ALE-AME 0.05, ALE-PLE contiguous, AME-AME 0.07, AME-PME 0.08, PLE-PME 0.06, PME-PME 0.27. Chelicera: 0.92 long/0.28 wide. Endite: 0.52 long/0.31 wide. Labium: 0.28 long/0.34 wide. Sternum: 0.90 long/1.09 wide. Legs: I 43.37 (10.93, 0.67, 11.20, 18.37, 2.20), II 29.06 (8.18, 0.71, 7.35, 11.37, 1.45), III 20.05 (5.91, 0.63, 4.91, 7.51, 1.09), IV 28.79 (9.88, 0.61, 6.73, 10.26, 1.31), tibia I L/d 61. Palp: 3.96 (0.78, 0.42, 1.14, - , 1.62). Abdomen: 3.94 long/2.29 wide.

Carapace pale yellowish brown, head region with blackish brown median and marginal bands, thoracic region with blackish brown radial and marginal bands (Fig. 2A). Chelicera with three apophyses; blunt proximo- lateral apophysis diagonally upward and protruding out of chelicera, small and blunt frontal apophysis protruding forward, and thick and pointed distal apophysis diagonally downward (Fig. 2C, D). Legs yellowish brown, retrolateral trichobothrium on tibia I at 6% proximally, tarsus I with 25> indistinct and irregular pseudosegments except 10 distally, femora and tibia with two proximal annuli and two distal annuli, metatarsi with one proximal anulus and one distal annulus, leg formula I-II-IV-III. Abdomen elliptical, pale yellowish brown with a long cardiac pattern and many black irregular spots (Fig. 2A). Palp (Fig. 2H-J): trochanter long and straight, shorter than femur; palpal tibia with semicircular prolatero-ventral modification (Fig. 2H); bulb pale yellowish brown, cordiform, appendix absent (Fig. 2H, K); uncus dark blackish brown, rounded square with smooth edge, pseudoappendix absent (Fig. 2H, K); embolus unmodified, weakly sclerotized with some semi-transparent distal fringed processes (Fig. 2H, K); procursus large and brown with dark blackish brown margin, distinct ventral knee present, membranous ventrally, two distal apophyses present, retrolatero-distal apophysis roundly depressed with blunt tip (numbered 1 in Fig. 2H-J), ventro-distal apophysis with bifurcate and pointed tips (numbered 2 in Fig. 2H-J).

Female. General appearance similar to male, habitus as in Fig. 2B. Total length 4.93. Carapace: 1.53 long/1.58 wide. Eyes: AER 0.60, PER 0.65, ALE 0.17, AME 0.10, PLE 0.15, PME 0.17, ALE-AME 0.03, ALE-PLE contiguous, AME-AME 0.07, AME-PME 0.07, PLE-PME 0.04, PME-PME 0.22. Chelicera: 0.81 long/0.26 wide. Endite: 0.51 long/0.27 wide. Labium: 0.30 long/0.27 wide. Sternum: 0.78 long/1.05 wide. Legs: I 31.57 (8.22, 0.69, 8.06, 12.42, 2.18), II 22.44 (6.19, 0.70, 5.56, 8.58, 1.41), III 16.50 (4.70, 0.62, 3.95, 6.10, 1.13), IV 22.44 (6.75, 0.63, 5.58, 8.28, 1.20), tibia I L/d 43. Palp: 1.28 (0.39, 0.18, 0.26, - , 0.45). Abdomen: 3.19 long/1.49 wide. Epigynum: 0.97 wide.

Epigynum (Fig. 2E, F): longer than wide, anteromedial portion slightly angular, anterior epigynal plate sclerotized with one pair of slightly depressed and triangular processes laterally, anterior epigynal plate strongly protruding, anterior epigynal plate and posterior epigynal plate contiguous, knob small and short with a blunt tip. Internal genitalia (Fig. 2G): anterior arch slightly recurved, pore plates elongate and narrow anterolaterally, far apart from each other.

Variation. Tibia I in three males (Holotype and paratypes): 10.58, 12.89, 11.88 (11.78±1.16). Tibia I in three females (Paratypes): 8.58, 8.57, 8.58 (8.58±0.01). Habitat. The species was collected by hand on rock walls and under rocks in mountainous mixed forest valley.

Distribution. Korea (Yeongheung-ri, Yeongweol-gun, Gangwon-do).