Cheiracanthium monstrum Zamani & Marusik, sp. nov.

Figs 2I‒J, 5A‒B, 7A‒C

Type material. Holotype ♂ and paratype 1♀ (ZMUT), IRAN: South Khorasan Prov.: Birjand, Behdan, 32°44'56"N 59°22'29"E, 2000 m, 25.06.2021 (M. Enayatnia).

Etymology. The specific epithet is a Latin adjective meaning ‘monster’.

Diagnosis. The male palp of the new species is similar to that of C. pelasgicum (C.L. Koch, 1837) but differs in having a relatively longer cymbial tip (length/width ratio of approximately 2 vs. 1.5), a relatively longer tibia (length/width ratio of 4 vs. 3), and a more bent cymbial spur (cf. Fig. 7A‒B and Seropian et al. 2023: figs 1‒2). The female of the new species is also similar to C. pelasgicum in the shape of the epigynal atrium but is unique among congeners in having sac-like structures (Sc) in the anterior part of the endogyne (Fig. 2I‒J), which are absent in all other related species.

Description. Male (holotype). Habitus as in Fig. 5A. Total length 8.25. Carapace 3.80 long, 2.75 wide. Eye sizes: AME: 0.21, ALE: 0.18, PME: 0.16, PLE: 0.15. Carapace, chelicerae, labium and maxillae reddish brown, cheliceral base black distally; sternum light brown. Chelicerae each with 5 retromarginal teeth and 1 conical basal hump on inner margin (Fig. 7C). Palps and legs buff yellow; cymbium and distal parts of tarsi dark brown. Abdomen light brown, dorsally with brown median band forming chevrons at posterior half. Spinnerets pale beige. Measurements of legs: I: 20.95 (5.56, 1.63, 5.85, 5.44, 2.47), II: 14.04 (3.76, 1.41, 3.73, 3.74, 1.40), III: 10.82 (3.05, 1.23, 2.42, 3.00, 1.12), IV: 14.82 (4.18, 1.44, 3.41, 4.40, 1.39).

Palp as in Fig. 7A‒B; tibia 4x longer than wide, tibial apophysis longer than tibia wide; cymbium ~ 3x longer than wide, with cymbial fold occupying 2/3 of cymbial length, cymbial spur almost as long as tibia; bulb oval, 1.7x longer than wide; tegular apophysis filamentous, almost straight, roundly bent terminally; conductor long, almost as long as bulb, with pointed tip; embolus originates at ~ 11:00 o’clock position.

Female (paratype). Habitus as in Fig. 5B. Total length 8.25. Carapace 3.80 long, 2.75 wide. Eye sizes: AME: 0.21, ALE: 0.18, PME: 0.16, PLE: 0.15. Carapace light brown; chelicerae, labium and maxillae reddish brown; sternum brown, with light brown median stripe. Chelicerae each with 3 pro- and 1 retromarginal teeth. Palps and legs yellowish brown, tarsi dark brown distally. Abdomen greyish beige, dorsally with brown median band at anterior half having pale yellow bands at sides, ventrally with two pale yellow bands. Spinnerets beige. Measurements of legs: I: 18.87 (5.02, 1.76, 4.92, 5.00, 2.17), II: 12.29 (3.41, 1.47, 3.10, 3.28, 1.03), III: 9.71 (2.74, 1.28, 2.08, 2.54, 1.07), IV: 14.31 (4.03, 1.49, 3.29, 4.14, 1.36).

Epigyne as in Fig. 2I‒J; epigynal plate 1.5x wider than long, fovea subtrapezoidal with rounded corners, wider anteriorly; insemination ducts (Id) forming 1 coil; anterior part of endogyne with subtriangular sacs (Sc); receptacles elongate, slightly thinner than sacs.

Distribution. Known only from the type locality in South Khorasan, eastern Iran.