Psechrus decollatus, Bayer, 2012

Bayer, Steffen, 2012, The lace-sheet-weavers — a long story (Araneae: Psechridae: Psechrus), Zootaxa 3379 (1), pp. 1-170 : 34-35

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 ).

Figures

FIGURES 14a–h. Psechrus decollatus sp. nov., from Indonesia, Java, Jawa Timur Prov. a–d ♂ paratype SB 857. e–h ♀ holotype SB 501. a–c ♂ palp (a prolateral, b ventral, c retrolateral view). d ♂ left palpal femur, retrolateral view. f Epigyne, ventral view. h Vulva, dorsal view. e Vulva, frontal view. g Schematic course of internal duct system. The asterisk indicates the peculiar, flattened, glossy field anterior to copulatory openings.

FIGURES 84a–i. Psechrus spp., photos of left ♂ palp, ventral view. a P. argentatus. b–c P. libelti. d P. kinabalu. e P.mulu. f P. ulcus sp. nov. g P. decollatus sp. nov. h P. singaporensis. i P.elachys sp. nov. a ♂ SB 1107 from Papua New Guinea. b s.a. ♂ syntype SB 339 from Indonesia, Sumatera Selatan Prov. c ♂ SB 203 from Thailand, Song Khla Prov. d ♂ holotype SB 237 from Malaysia, Borneo, Sabah Prov. e ♂ holotype SB 242 from Malaysia, Borneo, Sarawak Prov. f ♂ holotype SB 141 from Indonesia, Kalimantan Selatan Prov. g ♂ paratype SB 857 from Indonesia, Jawa Timur Prov. h ♂ SB 507 (syntype of P. curvipalpis) from Malaysia, Selangor Prov. i ♂ paratype SB 862 from Thailand, Satun Prov.

FIGURES 87a–k. Psechrus spp., photos of epigyne, ventral view. a P. argentatus. b P. libelti. c P. mulu. d P. borneo. e P. annulatus. f P. aluco sp. nov. g P. decollatus sp. nov. h P. singaporensis. i P. elachys sp. nov. j P.norops sp. nov. k P. arcuatus sp. nov. a ♀ SB 608 from Indonesia, Maluku Prov. b ♀ SB 969 from Brunei Darussalam. c ♀ paratype SB 239 from Malaysia, Borneo, Sarawak Prov. d ♀ holotype SB 279 from Indonesia, Kalimantan Timur Prov. e ♀ lectotype SB 829 from Indonesia, Jawa Tengah Prov. f ♀ holotype SB 123 from Indonesia, Jawa Barat Prov. g ♀ holotype SB 501 from Indonesia, Jawa Timur Prov. h ♀ SB 864 from Malaysia, Selangor Prov. i ♀ holotype SB 861 from Thailand, Satun Prov. j ♀ holotype SB 860 from Malaysia, Pahang Prov. k ♀ holotype SB 333 from Indonesia, Sumatera Barat Prov.

FIGURES 90a–k. Psechrus spp., photos of vulva, dorsal view. a P. argentatus. b P. libelti. c P. mulu. d P. borneo. e P. annulatus. f P. aluco sp. nov. g P. decollatus sp. nov. h P. singaporensis. i P. elachys sp. nov. j P.norops sp. nov. k P. arcuatus sp. nov. a ♀ SB 551 from Papua New Guinea, Morobe Prov. b ♀ SB 87 from Indonesia, Sumatra, Mentawei Islds. c ♀ SB 253 from Malaysia, Borneo, Sarawak Prov. d ♀ holotype SB 279 from Indonesia, Kalimantan Timur Prov. e ♀ lectotype SB 829 from Indonesia, Jawa Tengah Prov. f ♀ holotype SB 123 from Indonesia, Jawa Barat Prov. g ♀ holotype SB 501 from Indonesia, Jawa Timur Prov. h ♀ SB 220 from Singapore. i ♀ holotype SB 861 from Thailand, Satun Prov. j ♀ holotype SB 860 from Malaysia, Pahang Prov. k ♀ holotype SB 333 from Indonesia, Sumatera Barat Prov.

FIGURE 100. Distribution of Psechrus in eastern Malaysia and central Indonesia. Symbols (unicoloured): species belonging to the annulatus-group. Symbols (black, filled with light colour): species belonging to the mulu-group. Arrows: species belonging to the argentatus-group.