Psechrus insulanus, 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 : 21

Psechrus insulanus sp. nov.

Figs 11 , 25 D, 26D, 34

Type material. Holotype ♂ ( SB 1247 ): THAILAND: Phang Nga Prov.: Khuraburi Distr ., Ko Surin Nuea (means northern Surin island), behind Ao Chong Khad , 10–30 m, 09°25'25''N, 97°52'10''E, evergreen forest, P. Schwendinger leg. 17.– 18.XII.2012, sample number: TH-12/01 , MHNG.

Etymology. The specific name refers to the type locality, a small island close to the west coast of Southern Thailand (Latin “ insulanus ” means ‘inhabiting an island’); adjective.

Diagnosis (consider also the diagnosis for the himalayanus -group above): Males distinguished from those of all other species of the himalayanus -group, except P. jaegeri and P. vivax Bayer, 2012 , by the combination of the following characters: cymbial scopula absent ( Fig. 26 D); palpal tibia less than 1.4 times longer than broad; embolus curved, basally with ridges. Distinguished from the similar P. jaegeri and P. vivax by the following characters: Embolus shorter, and less curved ( Figs 11 B–C); retrolateral section of distal, narrower part of tegulum still visible in ventral view (see arrow in Fig. 11 B), not so in P. jaegeri and P. vi v ax; proximal section of sperm duct with slightly different course ( Figs 11 B, 25D), palpal tibia shorter than in P. jaegeri and P. vivax , hardly longer than broad ( Figs 11 A,C, 26D).

Description. Male: Body and eye measurements: Carapace length 8.5, maximal carapace width 6.4, anterior width of carapace 3.1, opisthosoma length 12.1, opisthosoma width 4.3. Eyes: AME 0.42, ALE 0.49, PME 0.51, PLE 0.47, AME–AME 0.32, AME–ALE 0.07, PME–PME 0.29, PME–PLE 0.38, AME–PME 0.83, ALE–PLE 0.61, clypeus height at AME 1.09, clypeus height at ALE 0.96.

Cheliceral furrow with three promarginal (four at right chelicera) and four retromarginal teeth.

Spination: Palp: 131, 110 (prolateral one less than half as long as dorsal one), 1101 (all spines less than half as long and broad as those on femur); legs: femur I 656{556}, II 566{556}, III–IV 555; patella I–IV 000; tibia I–II 3038, III 3134 (dorsal spine less than half as long and broad as others), IV 3136; metatarsus I–III 3035, IV 3034.

Measurements of palp and legs: Palp 9.8 [3.5, 1.7, 1.4, 3.2], I 75.5 [20.6, 4.3, 20.8, 21.1, 8.7], II 58.0 [16.1, 3.8, 15.2, 16.5, 6.4], III 40.7 [12.0, 2.9, 10.1, 10.9, 4.8], IV 60.9 [16.8, 3.4, 15.8, 17.4, 7.5]. Leg formula: 1423. FEMI+MTT-I/CL=4.91, thus, legs within the general range of males of the himalayanus -group (on average ca. 5).

Palpal femur without modification and straight ( Fig. 11 D). Macrosetae ventrally on coxae of leg I, which are typical for males of the himalayanus -group, present in male SB 1247, but clearly less developed than in other species like P. vivax or P. himalayanus Simon, 1906 .

Copulatory organ (see also diagnosis above and general description for himalayanus -group in Bayer 2012): Cymbium distally narrow ( Figs 11 A–C) and without dorsal scopula ( Fig. 26 D); tegulum ca. 1.7 times longer than broad ( Fig. 11 B, 25D); conductor with very fine, transparent and sail-shaped distal flange ( Fig. 11 B) and arising in a 11:30 o’clock position on tegulum; tubercles (tiny teeth) prolatero-ventrally on embolus hardly visible and thus finer than in P. j aegeri and P. vivax ; transversal section of sperm duct with slight curve centrally; subtegulum in ventral view only slightly protruding from underneath tegulum ( Fig. 11 B), but visible in prolateral view ( Fig. 11 A).

Colouration (see also description for himalayanus -group and Psechrus in Bayer 2012). Median bands on carapace serrated, lateral bands also serrated and if compared with other species of the himalayanus -group relatively narrow (broadest section ca. 1.2 diameter of PME). Light longitudinal line ventrally on opisthosoma continuous and narrow. If measured centrally on opisthosoma, its width is less than the width of one half of the cribellum (ca. 0.3–0.4 of one half of the cribellum).

Female: unknown.

Distribution. Thailand ( Fig. 34 ).

Figures

FIGURE 11. Psechrus insulanus sp. nov., male holotype (SB 1247, MHNG) from Ko Surin Nua, Phang Nga Prov., Thailand: left pedipalp. A: prolateral, B. ventral, C. retrolateral view. D. Palpal femur, retrolateral view. Arrow points at the retrolateral section of distal, narrower part of tegulum (still visible in ventral view).

FIGURE 25. Psechrus spp., photographic images of male pedipalps, ventral view. A. Psechrus rani. B. Psechrus arietinus sp. nov. (only bulb shown). C. Psechrus jaegeri. D. Psechrus insulanus sp. nov.. E. Psechrus ampullaceus sp. nov.. F. Psechrus obtectus. A. SB 1232, MHNG, from Ba Vi, Ha Noi Prov., Vietnam. B. Paratype SB 1186, AMNH, from Tra My, Quang Nam Prov., Vietnam. C. SB 1248, SMF 64074, from That I-Tou, Champasak Prov., Laos. D. Holotype (SB 1247, MHNG) from Ko Surin Nua, Phang Nga Prov., Thailand. E. Paratype SB 1241, MHNG, from Sa Pa, Lao Cai Prov., Vietnam. F. SB 1236, MHNG, from Doi Ngo, Bac Giang Prov., Vietnam.

FIGURE 26. Psechrus spp., photographic images of male pedipalps in prolateral (A – B) and retrolateral (C – F) view. A. Psechrus rani. B. Psechrus arietinus sp. nov.. C. Psechrus jaegeri. D. Psechrus insulanus sp. nov.. E. Psechrus ampullaceus sp. nov.. F. Psechrus obtectus. A. SB 1232, MHNG, from Ba Vi, Ha Noi Prov., Vietnam. B. Paratype SB 1186, AMNH, from Tra My, Quang Nam Prov., Vietnam. C. SB 1248, SMF 64074, from That I-Tou, Champasak Prov., Laos. D. Holotype (SB 1247, MHNG) from Ko Surin Nua, Phang Nga Prov., Thailand. A. Paratype SB 1241, MHNG, from Sa Pa, Lao Cai Prov., Vietnam. B. SB 1236, MHNG, from Doi Ngo, Bac Giang Prov., Vietnam.

FIGURE 34. Distribution of some Psechrus spp. and of Fecenia protensa in continental Southeast Asia.