Psechrus huberi, Bayer, Steffen, 2014

Bayer, Steffen, 2014, Seven new species of Psechrus and additional taxonomic contributions to the knowledge of the spider family Psechridae (Araneae), Zootaxa 3826 (1), pp. 1-54 : 36-38

Psechrus huberi sp. nov.

Figs 21 , 30 B, 33D, 36

Type material. Holotype ♀ ( SB 1194 ): PHILIPPINES: Luzon: Laguna Prov.: Los Baños , Makiling Forest Reserve , rain forest, ca. 170 m, 14°08'56.2''N, 121°13'56.8''E, S. Huber leg. 23.XI.2011, SMF.

Additional material (2 juveniles): All material with the same data as for holotype, 2 juvs ( SB 1195–1196 ), SMF.

Etymology. The specific name is a patronym in honour of Siegfried Huber, who collected the holotype of this new species and who has provided many Psechridae specimens for examination, collected during his many field excursions in SE Asia; term (name) in genitive case.

Diagnosis. Females distinguished from those of all other Psechrus species by the following combination of characters: (1) median septum laterally with characteristic flat, pointed extensions (extending “corners”) in posterior half ( Figs 21 A, 30B); (2) median septum anteriorly for the most part bordered by concave transverse ridges leading from antero-medial to the antero-lateral copulatory openings ( Figs 21 A, 30B); (3) Copulatory duct initially with very sharp “hairpin”-turn ( Figs 21 B–C), this more clearly recognisable in dorsal view ( Fig. 21 D).

Description. Male: unknown.

Female (both legs IV missing): Body and eye measurements: Carapace length 8.5, maximal carapace width 5.9, anterior width of carapace 3.7, opisthosoma length 12.1, opisthosoma width 4.9. Eyes: AME 0.42, ALE 0.45, PME 0.45, PLE 0.45, AME–AME 0.26, AME–ALE 0.10, PME–PME 0.27, PME–PLE 0.35, AME–PME 0.58, ALE–PLE 0.56, clypeus height at AME 1.53, clypeus height at ALE 1.33.

Cheliceral furrow with three promarginal and four retromarginal teeth. Palpal claw with 13 teeth.

Spination: Palp: 131, 110, 1101, 1014. Legs: femur I 667, II 667{669}, III 799{767}, IV –; patella I–III 0 0 0, IV: –; tibia I 3036, II 3036{4037}, III 3136{3135}, IV –; metatarsus I 2025, II 3035{3036}, III 3035, IV – both legs missing.

Measurements of palp and legs: Palp 9.9 [3.4, 1.4, 1.9, 3.2], I 57.8 [15.9, 3.8, 16.4, 15.8, 5.9], II 43.5 [12.2, 3.2, 11.6, 11.8, 4.7], III 29.6 [8.8, 2.5, 7.5, 7.5, 3.3], IV –.

Leg formula: -. FEM-I+MTT-I/CL=3.72, thus legs medium sized in relation to females of other Psechrus species.

Copulatory organ (see also diagnosis above): Copulatory openings located beneath arc-like swellings of lateral lobes; swellings located antero-laterally of antero-lateral sections of median septum ( Figs 21 A, 30B); median septum clearly broader than long; muscle sigilla anterior to epigyne ca. 1.5x longer than broad and of irregular shape; two slit sense organs proximal to the right muscle sigillum and one proximal to the left; referring from the situation in other Psechrus species the number of slit sense organs presumably varying from two to four epigynal field relatively inconspicuous, especially anteriorly, and clearly broader than long ( Figs 21 A, 30B). Spermathecal bases spherical, but not exactly round; spermathecal heads longer than broad, located postero-medially between spermathecal bases and final section of copulatory duct ( Figs 21 B, 33D).

Colouration of female (see also description for Psechrus in Bayer 2012): Median bands on carapace hardly serrated, lateral bands rather narrow (ca. diameter of PME). Sternum with dark tapered patch centrally, this occupying anterior ¾ of sternum. Sternum with light yellowish median line within that tapered patch. Light median line ventrally on opisthosoma present, relatively narrow and subdistally broken. Short distal section as broad as pre-subdistal section. If measured centrally on opisthosoma, the width of the light median line ventrally on opisthosoma is ca. 0.4x the width of one half of the cribellum.

Taxonomic remarks. Two more species, only known as males, are reported from Luzon: Psechrus schwendingeri Bayer, 2012 and P. w a de sp. nov. (species description see below). Conspecificity of P. huberi sp. nov. with one or other of them can be excluded as follows:

(1) P. schwendingeri: Even though adult females of this species are unknown, a characterisation of the preepigyne and pre-vulva of subadult females was possible ( Bayer 2012). The pre-vulva shows extremely flat prespermathecal heads that occupy most of the dorsal surface of the pre-receptacula ( Bayer 2012, fig. 78e). It is most unlikely that the final developmental step of the female copulatory organ of P. schwendingeri leads to a vulva structure like present in P. huberi sp. nov.. Moreover, the embolus of the male of P. schwendingeri is relatively short and stout. The copulatory duct of P. huberi sp. nov., however, is not particularly short. Consequently, I expect the male of P. huberi sp. nov. to possess an embolus that is longer than in P. schwendingeri .

(2) P. wade sp. nov.: The palp of the male of P. cebu Murphy, 1986 is very similar to that of P. wade sp. nov. (see species description and discussion below), consequently, a close relationship of these two species is highly likely. Accordingly, I expect the female of P. wade sp. nov. to have a longer median septum and less conspicuous spermathecal heads than in P. huberi sp. nov.. Moreover, molecular data of P. huberi sp. nov. and P. wade sp. nov. provides evidence that these two species are not conspecific. The COI sequences of both species were examined and a sequence distance of 9% was found. Additionally, the respective lineages were recovered at different positions within a certain subtree of a preliminary tree of the genus Psechrus , thus even a sister-group relationship is highly unlikely (Bayer, unpublished data).

Distribution. Philippines (Luzon) ( Fig. 36 ).

Figures

FIGURE 21. Psechrus huberi sp. nov., female holotype (SB 1194, SMF) from Los Baños, Laguna Prov., Luzon, Philippines: copulatory organ. A. Epigyne, ventral view. B – D. Vulva, dorsal (B) and frontal (D) view. C. Schematic course of internal duct system.

FIGURE 30. Psechrus spp., photographic images of epigynes, ventral view. A. Psechrus quasillus sp. nov.. B. Psechrus huberi sp. nov.. A. Holotype (SB 1224, MHNG) from Bau, Sarawak Prov., Borneo, Malaysia. B. Holotype (SB 1194, SMF) from Los Baños, Laguna Prov., Luzon, Philippines.

FIGURE 36. Distribution of Psechrus on the Philippines. The distribution of the already described species P. schwendingeri Bayer, 2012 and P. cebu Murphy, 1986 are shown for the purpose of comparison.