Psechrus chizami Sudhin, Sarma & Sen, 2025, sp. nov.
Creators: name: Sudhin, Puthoor Pattammal
name: Sarma, Shouvik Mali Pratyush Das
name: Sen, Souvik
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Psechridae
Psechrus
Psechrus chizami

description: Psechrus chizami sp. nov.
Figs 1–3, 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.
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, 2, 3).
Description. Female. (Holotype, NZC-ZSI-9431/18) (Figs 1–3) 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). Eye field light reddish-yellow to brown, covered with setae (Fig. 1A). Clypeus pale yellow, with light brown sides. Chelicerae dark reddish-brown, covered with setae (Fig. 1B). Endites light reddish-brown, scopulate, with pale yellow inner margins; sides covered with long black setae (Fig. 1B). Labium light reddish-brown, tip with pale yellow margin, covered with black setae (Fig. 1B). Sternum light brown, covered with long erect black setae, and short black setae; sides yellow, covered with short white setae (Fig. 1B). 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). Venter light greyish-brown, medially with pale-yellow longitudinal stripe, extending the entire length of opisthosoma, more prominent anteriorly (Fig. 1B). Spinnerets grey to greyish-brown (Fig. 1B). Genitalia as shown in Figs 1C–F, 2, 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, 2A, 3A); finger-like fertilization ducts visible laterally on the posterior borderline of the epigyne (Figs 1C, E, 3A); copulatory openings (CO) small, widely separated (Figs 1C, E, 3A); copulatory ducts (CD) long, forming a loop before entering the spermathecae posteriorly (Figs 1D, F, 2B–H, 3B); spermathecae (S) small, rounded (Figs 1D, F, 2C–H, 3B); fertilization ducts (FD) long, finger-like, and inwardly oriented (Figs 1D, F, 2B, G, 3B).
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).
description: Published as part of Sudhin, Puthoor Pattammal, Sarma, Shouvik Mali Pratyush Das & Sen, Souvik, 2025, Two new species of the spider genus Psechrus Thorell, 1878 (Araneae: Psechridae) from northeastern India, pp. 419-429 in Zootaxa 5609 (3) on pages 420-422, DOI: 10.11646/zootaxa.5609.3.7, http://zenodo.org/record/15215296