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

description: Psechrus decollatus sp. nov.
Figs 14a–h, 84g, 87g, 90g
Psechrus torvus — Simon 1906: 287 (Sub ‘ Nota ’: Record of a ♀ from Java, misidentified). Lehtinen 1967: 462, fig. 476 (Illustration of ♀, misidentified).
Type material: Holotype ♀ (SB 501), INDONESIA: Java, Jawa Timur Province: Bromo Tengger Semeru National Park, in surrounding area of Bromo Vulcano (‘ Mt. Tengger’); H. Fruhstorfer leg. 1891–1893; E. Simon det. P. torvus; P. Lehtinen vid.; Simon-Coll.-No. 15048; MNHN AR173. Paratype ♂ (SB 857, poor condition, opisthosoma lost), with same data as for holotype, except: H. Levi det. “fragments of Psechrus male, n. sp.?“ 1982; ZMB 19241.
Additional material examined. INDONESIA: Java, Jawa Timur Province: Bromo Tengger Semeru National Park, in surrounding area of Bromo Vulcano (‘ Mt. Tengger’); H. Fruhstorfer leg. 1891–1893; 1 juv. (SB 859, poor condition, opisthosoma lost), ZMB 19241.
Additional doubtful material examined. In the same series like paratype and SB 859; 1 s.a. ♀ or ♀? (SB 858, poor condition, opisthosoma lost), ZMB 19241.
Etymology. The specific name refers to the vulva of this species, which lacks spermathecal heads (Latin “decollare” means “behead”); past participle passive.
Diagnosis (see also diagnosis for annulatus -group above). In males embolus (E) long (almost as long as tegulum [T]) and almost straight (in lateral view at most slightly S-curved) (Figs 14a–c), running along longitudinal axis of cymbium and arising prolaterally at embouls base (EB). Distal half of conductor (C) ca. 2x broader than basal one. Females similar to P. annulatus in basic shape of median septum (MS). Distinguished by the spermathecae lacking heads (SH), the relatively small copulatory ducts (CD) running mainly in dorso-ventral direction (Figs 14e,h) and the narrower MS.
Description. Male:
Body and eye measurements. Carapace length 5.1, carapace width 3.4, anterior width of carapace 1.9, opisthosoma length—, opisthosoma width—. Eyes: AME 0.31, ALE 0.36, PME 0.35, PLE 0.36, AME–AME 0.18, AME–ALE 0.06, PME–PME 0.24, PME–PLE 0.28, AME–PME 0.46, ALE–PLE 0.34, clypeus height at AME 0.64, clypeus height at ALE 0.49.
Cheliceral furrow with three promarginal and four (five, right) retromarginal teeth.
Measurements of palp and legs. Leg formula: 1423. Palp: 6.4 [2.3, 1.1, 0.9, 2.1]; Legs: I 53.9 [14.2, 2.3, 14.4, 15.0, 8.0], II 39.8 [10.8, 2.0, 10.2, 11.2, 5.6], III 27.3 [7.7, 1.6, 6.7, 7.4, 3.9], IV 42.3 [12.1, 1.8, 10.4, 11.7, 6.3].
Spination. Palp: 141, 110{010}, 1101 (all palpal tibia spines very small); legs: femur I 565, II 555, III 545, IV 534; patella I–IV 000; tibia I 3038, II 4038, III 3034, IV 3036; metatarsus I 4035, II–IV 3035.
Palpal femur slim, modified with a flat ventral bulge (Fig. 14d), distinctly flatter than e.g. in Psechrus singaporensis. Palpal tibia relatively short, distally broader than proximally (Figs 14a–c). MC-I–II and MT-I absent.
Copulatory organ (see also diagnosis and general description for annulatus -group). T slightly longer than broad. C in lateral view slightly curved (Figs 14a,c).
Female:
Body and eye measurements. Carapace length 5.8, carapace width 4.0, anterior width of carapace 2.4, opisthosoma length 8.9, opisthosoma width 3.3. Eyes: AME 0.34, ALE 0.43, PME 0.43, PLE 0.42, AME–AME 0.18, AME–ALE 0.09, PME–PME 0.27, PME–PLE 0.34, AME–PME 0.49, ALE–PLE 0.47, clypeus height at AME 0.85, clypeus height at ALE 0.63.
Cheliceral furrow with three promarginal and four (+ 1 very small tooth proximally with less than one third the size of the others) retromarginal teeth.
Measurements of palp and legs. Leg formula: 1423. Palp: 7.2 [2.4, 1.0, 1.4, 2.4]; Legs: I 39.6 [10.6, 2.3, 11.1, 9.9, 5.7], II 30.6 [8.6, 2.1, 7.9, 7.7, 4.3], III 21.7 [6.4, 1.7, 5.2, 5.3, 3.1], IV 32.4 [9.2, 2.0, 8.3, 8.3, 4.6].
Palpal claw with 14 teeth.
Spination. Palp: 141, 110, 1101, 1014; legs: femur I 536, II 546{556} III 555, IV 545; patella I–IV 000; tibia I–II 3035, III 3134 (dorsal spine very small), IV 3034; metatarsus I–IV 3035.
Copulatory organ (see also diagnosis and general description of annulatus -group). Epigyne with peculiar, flattened field anterior to copulatory openings (CO) (asterisk in Fig. 14f). MS posteriorly just a bit broader than anteriorly (Fig. 14f). Epigynal muscle sigilla (EM) rather elongated. Slit sense organs and EM outside epigynal field. Spemathecae cross-oval and covering most parts of CD if vulva is viewed from dorsal (Fig. 14h). In frontal view course of CD becomes clear (Fig. 14e).
Colouration of male and female (see also description for annulatus -group and Psechrus). Lateral bands broad (ca. 1.6x diameter PME) and slightly serrated.
Remark. It is highly likely that the adult female (SB 501) originated from the same series as the specimens from ZMB, Berlin. Presumably already in the beginning of the 20 th century it had reached MNHN, Paris (possibly in exchange). The specimens, which remained in ZMB unfortunately got into poor condition over time (possibly during confusion of the World War[s]). All the specimens from ZMB 19241 are lacking their opisthosomas. I consider SB 859 to be a juvenile ♀ (younger than a subadult).
Concerning SB 858, I assume that it is either an adult or a subadult ♀. However, I have major doubts if this specimen belongs to P. decollatus sp. nov. The colouration of carapace as well as sternum clearly differ from general pattern of annulatus -group. The tapered patch centrally on sternum is rather narrow. The lateral bands on carapace are very narrow (like in representatives of sinensis -group, see below). Apparently this specimen was added to the series 19241 at a later date, without any note.
Distribution. Indonesia [Java] (Fig. 100).
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 34-35, DOI: 10.11646/zootaxa.3379.1.1, http://zenodo.org/record/6039832