Psechrus laos Bayer 2012, sp. nov.
Creators: name: Bayer, Steffen
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Psechridae
Psechrus
Psechrus laos

description: Psechrus laos sp. nov.
Figs 25a–f, 26a–d, 85c, 88c, 91c
Type material: Holotype ♂ (SB 367), LAOS: Bolikhamsay Province: Lak Sao |1|, N 18°11'09.0'', E 104°53'55.0'', 500 m, between rocks; P. Jäger & S. Bayer leg. 08.XI.2009; SMF. Paratypes: ♂ (SB 355), ♀ (SB 368), same data as for holotype; SMF; 3 ♀♀ (SB 372–374), Lak Sao |4|, N 18°13'38.2'', E 104°44'47.3'', 534 m, cave entrance, between rocks; P. Jäger & S. Bayer leg. 09.XI.2009; SMF; 2 ♀♀ (SB 377–378), Lak Sao, Tham Mang Kone, N 18°13'16.1'', E 104°48'45.9'', 500 m, cave entrance; P. Jäger & S. Bayer leg. 09.XI.2009; SMF.
Additional material examined (5 s.a. ♂♂, 1 s.a. ♀, 2 juvs). LAOS: Bolikhamsay Province: Lak Sao |1|, N 18°11'09.0'', E 104°53'55.0'', 500 m, between rocks; P. Jäger & S. Bayer leg. 08.XI.2009; 3 s.a. ♂♂ (SB 341, 345, 370), 1 s.a. ♀ (SB 406), 1 juv. (SB 369), SMF. Lak Sao |4|, N 18°13'38.2'', E 104°44'47.3'', 534 m, cave entrance, between rocks; P. Jäger & S. Bayer leg. 09.XI.2009; 1 s.a. ♂ (SB 343), 1 juv. (SB 376), SMF. Lak Sao, Tham Mang Kone, N 18°13'16.1'', E 104°48'45.9'', 500 m, cave entrance; P. Jäger & S. Bayer leg. 09.XI.2009; 1 s.a. ♂ (SB 354), SMF
Etymology. The specific name refers to the habitat of this species (Ancient Greek “las” means “stone, rock, crag”; genitive case: “laos”); noun in genitive case.
Diagnosis (see also diagnosis for ancoralis -group above). Males similar to P. rani in having a large conductor base (CB). Distinguished by the very long embolus (E) (clearly longer than tegulum [T]) and the larger, voluminous CB (Figs 25a–c). Females similar to P. rani in shape of median septum (MS) and general shape of vulva (see diagnosis P. rani). Distinguished by the higher (longer) helical spermathecal section of vulva with more than three windings (Fig. 25d) and by the distance between the two epigynal muscle sigilla (EM), which is not or just slightly longer than the width of MS (Figs 25f, 26c).
Description. Male (measurements of holotype first, those of paratype SB 355 in parentheses):
Body and eye measurements. Carapace length 6.0 (4.8), carapace width 4.1 (3.4), anterior width of carapace 2.4 (1.9), opisthosoma length 7.3 (6.2), opisthosoma width 3.4 (2.7). Eyes: AME 0.37 (0.33), ALE 0.43 (0.39), PME 0.45 (0.41), PLE 0.44 (0.41), AME–AME 0.16 (0.15), AME–ALE 0.02 (0.03), PME–PME 0.18 (0.16), PME–PLE 0.31 (0.28), AME–PME 0.55 (0.49), ALE–PLE 0.32 (0.29), clypeus height at AME 0.82 (0.74), clypeus height at ALE 0.71 (0.64).
Cheliceral furrow with three promarginal and five retromarginal teeth.
Measurements of palp and legs. Leg formula: 1423. Palp 8.1 (6.8) [2.8 (2.4), 1.2 (0.9), 1.2 (1.0), 2.9 (2.5)], I 54.9 (46.5) [14.2 (11.5), 2.6 (2.2), 15.3 (12.8), 16.0 (14.0), 6.8 (6.0)], II 42.5 (35.2) [12.0 (9.3), 2.4 (2.1), 10.9 (9.1), 12.0 (10.4), 5.2 (4.3)], III 30.0 (23.4) [8.7 (6.7), 2.0 (1.7), 7.2 (5.6), 8.2 (6.4), 3.9 (3.0)], IV 44.3 (36.8) [12.3 (10.0), 2.2 (1.8), 11.2 (9.3), 12.4 (10.3), 6.2 (5.4)].
Spination. Palp: 131 (141), 010 (010), 0100 (0100); legs: femur I 656 (556), II 555 (556) III 555 (555), IV 545{554} (545); patella I–IV 000; tibia I 3039 (3038), II 3038 (3039), III 3036 (3036), IV 3035 (3036); metatarsus I 3037 (3035), II 3035 (3035), III 3035 (2023), IV 3035{3036} (3036).
Palpal femur without modification, shaped like in P. antraeus (see below).
Copulatory organ (see also diagnosis and general description for ancoralis -group). Proximal section of T short. CB medio-distally with semicircular notch (Fig. 25b). Palpal tibia short (Fig. 25a,c).
Female:
Body and eye measurements. Carapace length 5.1–7.6, carapace width 3.4–5.2, anterior width of carapace 2.3–3.3, opisthosoma length 6.9–11.9, opisthosoma width 3.9–5.9. Eyes: AME 0.34–0.38, ALE 0.44–0.47, PME 0.41–0.46, PLE 0.42–0.46, AME–AME 0.18–0.21, AME–ALE 0.06–0.08, PME–PME 0.22–0.24, PME–PLE 0.32–0.36, AME–PME 0.49–0.60, ALE–PLE 0.38–0.47, clypeus height at AME 0.86–1.01, clypeus height at ALE 0.79–0.97.
Cheliceral furrow with three promarginal and five retromarginal teeth.
Measurements of palp and legs. Leg formula: 1423. Palp: 6.4–9.2 [2.2–3.1, 1.0–1.3, 1.1–1.7, 2.1–3.1]; Legs: I 34.4–47.5 [9.5–13.3, 2.1–3.3, 9.8–12.3, 8.6–12.7, 4.4–5.9], II 27.3–38.2 [7.8–10.9, 2.0–3.0, 7.2–10.0, 6.8–9.7, 3.5–4.6], III 19.0–27.9 [6.0–8.3, 1.4–2.3, 4.6–6.8, 4.5–7.1, 2.5–3.4], IV 28.4–39.2 [8.0–11.2, 1.9–2.6, 7.4–10.1, 7.3–10.1, 3.8–5.2].
Palpal claw with 14–15 teeth.
Spination. Palp: 131, 110, 1101, 1014 (1015); legs (—except for patella— variable, only most common states noted): femur I 556 (557,566), II 556, III 556 (555), IV 544 (554); patella I–IV 000; tibia I–II 3038, III 3036 (3035,3026), IV 3035 (3036,3037); metatarsus I–III 3035, IV 3034 (3036).
Copulatory organ (see also diagnosis and general description of ancoralis -group). Lateral margins of MS anteriorly strongly curved. MS showing two, slightly curved longitudial ridges posterior to copulatory openings (Figs 25f, 26c), which are generally more distinct than in P. rani. Epigynal field mostly absent, if present, then indistinct.
Primordial copulatory organ. Pre-epigyne: Pre-septum relatively long, with two fine transversal edges in posterior half (Fig. 26a).
Pre-vulva: Pre-copulatory duct just slightly curved (Fig. 26b), pre-spermatheca and pre-spermathecal head quite compact.
Colouration of male and female (see also description for ancoralis -group and Psechrus). Median bands on carapace serrated. Lateral bands narrow (ca. 1/2 diameter of PME) and serrated. Light longitudinal line ventrally on opisthosoma continuous and rather narrow. If measured centrally on opisthosoma, its width is ca. 1/2 the width of one half of the cribellum.
Variation of copulatory organs. Males: Variation only insignificant. Females: Epigyne may be with indistinct (Fig. 26c) or without epigynal field (Fig. 25f). The two, slightly curved longitudial ridges posterior to the area of copulatory openings differ in length and structure (Figs 25f, 26c). Lateral margins of MS may be parallel (Fig. 26c) or converging somewhat (Fig. 25f, 88c). In vulva the length of helical spermathecal section differs (Fig. 25d, 26d) at high level.
Distribution. Laos (Fig. 98).
description: Published as part of Bayer, Steffen, 2012, The lace-sheet-weavers — a long story (Araneae: Psechridae: Psechrus), pp. 1-170 in Zootaxa 3379 (1) on pages 53-56, DOI: 10.11646/zootaxa.3379.1.1, http://zenodo.org/record/6039832