Psechrus chizami, Sudhin & Sarma & Sen, 2025

Psechrus chizami sp. nov.

Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 , 8 View FIGURE 8

Type material. Holotype ♀ ( NZC-ZSI-9428/18 ) from INDIA: Nagaland: Phek District, Chizami (25°35’49”N 94°23’09”E), 1400 m a.s.l., 02.III.2024, leg. P. P. Sudhin. GoogleMaps

Etymology. The species is named after its type locality, Chizami, a small village in Nagaland, North East India. The name is treated as a noun in apposition.

Diagnosis. Psechrus chizami sp. nov. can be easily distinguished from those of all other Psechrus species by its unique epigynal morphology: epigyne possesses a broad median septum (MS), with its anterio-central section forming an atrium bordered by a sclerotized rim, giving it an ear-muff-like appearance; copulatory ducts long, forming a loop before entering the spermathecae posteriorly; spermathecae rounded ( Figs 1C–F View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 ).

Description. Female. (Holotype, NZC-ZSI-9431/18) ( Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 ) Measurements: body length 20.92; carapace length 9.82, width 6.67, anterior width of carapace 4.28; opisthosoma length 11.10, width 6.04. Eye diameters: AME 0.40, ALE 0.51, PME 0.59, PLE 0.52. Eye interdistances: AME–AME 0.24, AME–ALE 0.07, ALE–ALE 1.02, PLE–PLE 1.84, PME–PME 0.24, PME–PLE 0.36, AME–PME 0.54, ALE–PLE 0.46. Clypeus height at AME 0.81, clypeus height at ALE 0.63. Chelicerae 3.12 long, with 2 promarginal and 4 retromarginal teeth. Measurement of palp and legs: Palp: 10.73 [4.13, 1.45, 1.96, 3.19], legs I 55.82 [14.68, 3.99, 16.42, 14.08, 6.65], II 45.1 [12.38, 3.20, 12.86, 11.08, 5.58], III 30.18 [9.46, 2.16, 7.56, 7.28, 3.27], IV 45.43 [13.54, 3.18, 12.09, 11.24, 5.38]. Leg formula: 1423. Spination. Palp: femur pl 1 rl 1 do 3, patella pl 1 do 1, tibia pl 2 do1, tarsus pl 2 rl 2 plv 1. Legs: femur I–II pl 5 rl 6 do 5, III–IV pl 5 rl 5 do 5; tibia I–II pl 3 rl 3 plv 4 rlv 4, III pl 3 rl 3 plv 2 rlv 2, IV pl 3 rl 3 plv 3 rlv 3; metatarsus I–II pl 1 rl 1 plv 4 rlv 4 v 1, III–IV pl 2 rl 2 plv 3 rlv 3 v 1; tarsus I–IV spineless. Carapace pale yellow, covered with black setae, with a broad light brown median band, and narrow light brown lateral bands; median band with a broad pale-yellow marking anteriorly, and triangle-shaped pale-yellow marking posteriorly, sides of median band undulating; lateral bands extending from behind PLE ( Fig. 1A View FIGURE 1 ). Eye field light reddish-yellow to brown, covered with setae ( Fig. 1A View FIGURE 1 ). Clypeus pale yellow, with light brown sides. Chelicerae dark reddish-brown, covered with setae ( Fig. 1B View FIGURE 1 ). Endites light reddish-brown, scopulate, with pale yellow inner margins; sides covered with long black setae ( Fig. 1B View FIGURE 1 ). Labium light reddish-brown, tip with pale yellow margin, covered with black setae ( Fig. 1B View FIGURE 1 ). Sternum light brown, covered with long erect black setae, and short black setae; sides yellow, covered with short white setae ( Fig. 1B View FIGURE 1 ). Legs pale yellow, reddish-brown towards the distal segments. Opisthosoma dorsally pale yellow to greyish-brown, covered with light brown setae, anteriorly with median spindle-shaped pale yellow marking; laterally with dark-brown and white longitudinal stripes ( Fig. 1A View FIGURE 1 ). Venter light greyish-brown, medially with pale-yellow longitudinal stripe, extending the entire length of opisthosoma, more prominent anteriorly ( Fig. 1B View FIGURE 1 ). Spinnerets grey to greyish-brown ( Fig. 1B View FIGURE 1 ). Genitalia as shown in Figs 1C–F View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 . Epigynal field wider than long; median septum (MS) wider than long, concave with several wrinkles, and its anterio-central section forming an atrium (A) bordered by a sclerotized rim, giving it an ear-muff-like appearance ( Figs 1C, E View FIGURE 1 , 2A View FIGURE 2 , 3A View FIGURE 3 ); finger-like fertilization ducts visible laterally on the posterior borderline of the epigyne ( Figs 1C, E View FIGURE 1 , 3A View FIGURE 3 ); copulatory openings (CO) small, widely separated ( Figs 1C, E View FIGURE 1 , 3A View FIGURE 3 ); copulatory ducts (CD) long, forming a loop before entering the spermathecae posteriorly ( Figs 1D, F View FIGURE 1 , 2B–H View FIGURE 2 , 3B View FIGURE 3 ); spermathecae (S) small, rounded ( Figs 1D, F View FIGURE 1 , 2C–H View FIGURE 2 , 3B View FIGURE 3 ); fertilization ducts (FD) long, finger-like, and inwardly oriented ( Figs 1D, F View FIGURE 1 , 2B, G View FIGURE 2 , 3B View FIGURE 3 ).

Male. Unknown.

Note. Based on the unique structure of its female genitalia (see diagnosis), this new species cannot be assigned in any currently known species group.

Distribution. Known only from the type locality in India (Nagaland) ( Fig. 8 View FIGURE 8 ).