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

description: Psechrus ulcus sp. nov.
Figs 10a–e, 84f
Type material: Holotype ♂ (SB 141), INDONESIA: Borneo, Kalimantan Selatan Province: ca. 25 km E of Banjarbaru, near Riamkanan Dam, S 3°30'59'', E 115°01'00'', 50 m, primary forest; P. Schwendinger leg. 29.–31.X.2008; MHNG.
Etymology. The specific name refers to the striking retrolateral process on palpal tibia (Latin “ulcus” means “excrescense, branch”); term (noun) in apposition.
Diagnosis (see also diagnosis for mulu -group above). Male with impressive bulky embolus base (EB) and embolus (E) (Figs 10a–c) apically on tegulum (T), both with several ridges. E directed retrolaterally.
Description. Male:
Body and eye measurements. Carapace length 4.9, carapace width 3.1, anterior width of carapace 1.6, opisthosoma length 7.5, opisthosoma width 2.3. Eyes: AME 0.29, ALE 0.34, PME 0.35, PLE 0.34, AME–AME 0.20, AME–ALE 0.06, PME–PME 0.21, PME–PLE 0.26, AME–PME 0.42, ALE–PLE 0.36, clypeus height at AME 0.71, clypeus height at ALE 0.50.
Cheliceral furrow with three promarginal and four retromarginal teeth.
Measurements of palp and legs. Leg formula: 1423. Palp: 5.8 [2.1, 1.0, 0.9, 1.8]; Legs: I 65.8 [17.0, 2.0, 17.7, 20.0, 9.1], II 47.5 [12.7, 1.8, 11.7, 14.2, 7.1], III 32.6 [9.0, 1.4, 8.0, 9.6, 4.6], IV 50.6 [13.7, 1.6, 11.8, 15.7, 7.8].
Spination. Palp: 131, 110{000}, 1101{0000}; legs: femur I 667, II 666, III 656, IV 556; patella I–IV 000; tibia I 4048, II 3038, III 3136, IV 4146; metatarsus I–IV 3035.
Palpal femur bulky —but less distinct than in P. mulu — and modified with a rather pointed ventral extension. Its tip slightly pointing distally (Fig. 10d). Palpal trochanter distally with 10–15 macrosetae (Fig. 10e). Palpal tibia short, distally broader than proximally and with retrolateral process. The latter with long bristles (Fig. 10b).
Copulatory organ (see also diagnosis and general description for mulu -group). T shorter than in P. mulu, centrally with distinctly light area, which is surrounded by sperm duct (Figs 10b, 84f) and prolatero-distally with ‘corner’ (Figs 10b, 84f). Cymbium dorsally with very dense scopula, covering ca. 1/3 of cymbium.
Female: unknown.
Colouration (see also description for mulu -group and Psechrus). Median bands on carapace serrated. Lateral bands medium-sized to broad (1.5x diameter of PME) and not serrated. Sternum yellowish brown posteriorly and at lateral margins and with light brown tapered patch centrally. These two sections are not easy to discriminate due to the small colour differences.
Distribution. Indonesia [Southern Borneo] (Fig. 100).
Remarks: For the following reasons it is unlikely that the male holotype represents the conspecific male of P. borneo: 1) The type localities are ca. 700 km away from each other; 2) The females of P. mulu and P. borneo are similar. Consequently, for P. borneo I would anticipate a male that is similar to P. mulu. However, this does not apply to P. ulcus sp. nov., as its bulb differs clearly from the one of P. mulu.
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 28-29, DOI: 10.11646/zootaxa.3379.1.1, http://zenodo.org/record/6039832