Psechrus elachys, Bayer, 2012

Bayer, Steffen, 2012, The lace-sheet-weavers — a long story (Araneae: Psechridae: Psechrus), Zootaxa 3379 (1), pp. 1-170 : 41-43

publication ID	https://doi.org/ 10.11646/zootaxa.3379.1.1
DOI	https://doi.org/10.5281/zenodo.6303156
persistent identifier	https://treatment.plazi.org/id/D0272654-FFA8-5869-FF20-2ABCFDE04545
treatment provided by	Felipe
scientific name	Psechrus elachys
status	sp. nov.

Treatment

Psechrus elachys View in CoL sp. nov.

Figs 17a–g View FIGURES 17 , 82f View FIGURES 82 , 83d View FIGURES 83 , 84i View FIGURES 84 , 87i View FIGURES 87 , 90i View FIGURES 90

Type material: Holotype ♀ (SB 861), THAILAND: Satun Province: Thale Ban National Park , N 06°42', E 100°10', 350–400 m, lowland rain forest; M. Andersen, O. Martin and N. Scharff leg. 20.X.1991; ZMUC 4538 GoogleMaps . Paratype ♂ (SB 862), with same data as for holotype; ZMUC 4538 GoogleMaps .

Etymology. The specific name refers to the small body size of the holotype female (Ancient Greek “elachys” means “little, small, short”); term (adjective) in apposition.

Diagnosis (see also diagnosis for singaporensis -group above). In males embolus (E) in ventral view narrower than in P. singaporensis , erected steep and its tip more clearly pointed ( Figs 17b–c View FIGURES 17 ) than in P. singaporensis . Embolus base (EB) protruding beyond upper retrolateral margin of tegulum (T) ( Fig. 17b View FIGURES 17 ). E ventrally with creaselike structure ( Figs 17b–c View FIGURES 17 ). Females similar to P. singaporensis in having a rather simple median septum (MS) and medium sized copulatory ducts (CD) with spermathecal heads (SH) located upon distal section —thus the section close to spermatheca— of CD ( Figs 15e–f,h–i View FIGURES 15 , 17d–e View FIGURES 17 ). Distinguished by the small copulatory opening (CO) pointing anteriorly ( Figs 17d View FIGURES 17 , 87i View FIGURES 87 ), leading to a different course of CD ( Fig. 17f View FIGURES 17 cf. Fig. 15g View FIGURES 15 ). CD a bit narrower and shorter ( Fig. 17e View FIGURES 17 , 90i View FIGURES 90 ) than in singaporensis .

Description. Male:

Body and eye measurements. Carapace length 5.1, carapace width 3.3, anterior width of carapace 1.8, opisthosoma length 6.0, opisthosoma width 2.2. Eyes: AME 0.29, ALE 0.35, PME 0.35, PLE 0.33, AME–AME 0.15, AME–ALE 0.06, PME–PME 0.22, PME–PLE 0.22, AME–PME 0.38, ALE–PLE 0.34, clypeus height at AME 0.49, clypeus height at ALE 0.38.

Cheliceral furrow with three promarginal and four retromarginal teeth.

Measurements of palp and legs. Leg formula: 1423. Palp: 5.8 [2.1, 1.0, 0.8, 1.9]; Legs: I 56.0 [14.9, 2.3, 14.9, 16.2, 7.7], II 40.9 [11.4, 1.9, 10.3, 11.5, 5.8], III 26.8 [7.6, 1.5, 6.6, 7.3, 3.8], IV 43.7 [12.1, 1.7, 10.5, 13.1, 6.3].

Spination. Palp: 131, 110 (both very small), 1101 (all very small); legs: femur I 656, II 666, III–IV 555; patella I–IV 000; tibia I 3038, II 3036, III–IV 3136; metatarsus I–IV 3035.

Palpal femur modified with rounded ventral bulge ( Fig. 17g View FIGURES 17 ). MC-I and MT-I: present, but just as apical row.

Copulatory organ (see also diagnosis and general description for singaporensis -group). Conductor (C) shape similar to P. singaporensis , but C arising subdistally at prolateral section of T ( Figs 17a–b View FIGURES 17 ). Palpal tibia ( Fig. 17a–c View FIGURES 17 ) very similar to P. singaporensis .

Female (both legs II are missing):

Body and eye measurements. Carapace length 5.1, carapace width 3.6, anterior width of carapace 2.1, opisthosoma length 8.5, opisthosoma width 3.3. Eyes: AME 0.32, ALE 0.38, PME 0.38, PLE 0.38, AME–AME 0.21, AME–ALE 0.06, PME–PME 0.23, PME–PLE 0.31, AME–PME 0.45, ALE–PLE 0.38, clypeus height at AME 0.81, clypeus height at ALE 0.62.

Cheliceral furrow with three promarginal and four retromarginal teeth.

Measurements of palp and legs. Leg formula:? Palp: 6.5 [2.2, 0.9, 1.3, 2.1]; Legs: I 42.5 [11.6, 2.2, 11.8, 11.1, 5.8], III 22.0 [6.7, 1.4, 5.4, 5.6, 2.9], IV 33.7 [9.8, 1.7, 8.7, 8.6, 4.9].

Palpal claw with 14 teeth.

Spination. Palp: 131, 110, 1101, 1014; legs: femur I 656, III 555, IV 545; patella I–IV 000; tibia I 3038, III–IV 3136; metatarsus I&III 3035, IV 3036.

Copulatory organ (see also diagnosis and general description of singaporensis -group). MS more or less trapezoid ( Fig. 17d View FIGURES 17 ). Slit sense organs and epigynal muscle sigilla outside epigynal field. CD with winding for 1/4 length at most until reaching receptaculum ( Fig. 17e View FIGURES 17 ), ca. 1.5x longer than diameter of receptaculum.

Colouration of male and female (see also description for singaporensis -group and Psechrus ). Median bands on carapace serrated ( Fig. 82f View FIGURES 82 ). Width of lateral bands ca. 1.4x diameter of PME and serrated.

Distribution. Thailand ( Fig. 99 View FIGURE 99 ).