Psechrus arietinus, sp. nov.
Creators: name: Bayer, Steffen
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Psechridae
Psechrus
Psechrus arietinus

description: Psechrus arietinus sp. nov.
Figs 7–10, 25 B, 26B, 28D, 31D, 34
Type material. Holotype ♀ (SB 1189): VIETNAM: Quang Nam Prov.: Tra My, Ngoc Linn Range, “along Mt. Range slope”, 935 m, ca. 15°17'N, 108°14'E, X.-P. Wang leg. 09.IV.1999, AMNH. – Paratypes (1 ♂, 11 ♀; all material with the same geographical data [Tra My, Ngoc Linn Range], the same geographic coordinates, except where otherwise noted, and collected by X.-P. Wang, but with the following recorded locality and date): 1 ♂ (SB 1186; note: both palps were found irreversibly expanded): Camp I, “along Rive down” 940 m, 31.III.1999, AMNH. – 5 ♀ (SB 1159, 1190–1193): Camp I, “along Rive down ”, 940 m, 01.IV.1999, AMNH. – 1 ♀ (SB 1184): “up the slope”, 935 m, 07.IV.1999, AMNH. – 1 ♀ (SB 1214): “ Camp I to Big River ”, 750– 950 m, 16.IV.1999, MHNG. – 1 ♀ (SB 1215): “ Camp I to Big River ”, 750– 950 m, 16.IV.1999, AMNH. – 1 ♀ (SB 1188): Camp I, 1290– 1470 m, ca. 15°16'N, 108°14'E, 08.IV.1999, AMNH. – 1 ♀ (SB 1185): “ Big River ”, 750 m, ca. 15°18'N, 108°15'E, 13.IV.1999, MHNG. – 1 ♀ (SB 1187): “ Big River ”, 750 m, ca. 15°18'N, 108°15'E, 13.IV.1999, AMNH.
Etymology. The specific name refers to the female epigyne (exhibiting glossy, bulgy fields surrounding the copulatory openings) reminiscent of the head of a ram (Latin “arietinus” means ‘similar to a ram’); adjective.
Diagnosis (refer also to diagnosis of himalayanus -group above): Males distinguished from those of all other species of the himalayanus -group, except P. ghecuanus Thorell, 1897 and P. pakawini Bayer, 2012, by the combination of the following characters: cymbial scopula absent; palpal tibia at most 1.4 times longer than broad; embolus straight; tegulum apically with strongly sclerotised, almost semicircular extension. Distinguished from P. ghecuanus and P. pakawini by: retrolateral edge of semicircular extension apically on tegulum distinctly extending proximally, ending clearly proximal to the arising point of embolus (Fig. 8 B), basal fourth of tegulum distinctly narrower than central section of tegulum (Fig. 8 B).
Females distinguished from those of all other species of the himalayanus -group by the following characters in combination: Median septum generally longer than broad (Figs 9 A, 10A, 28D); copulatory duct, with its initial course from anterio-lateral to medial direction, visibly longer than diameter of one receptaculum (Fig. 9 B–C), especially obvious if viewed from anterior (Fig. 9 D).
Description. Male (paratype SB 1186): Body and eye measurements: Carapace length 7.6, maximal carapace width 4.3, anterior width of carapace 3.1, opisthosoma length 10.1, opisthosoma width 3.7. Eyes: AME 0.39, ALE 0.46, PME 0.50, PLE 0.49, AME–AME 0.27, AME–ALE 0.04, PME–PME 0.27, PME–PLE 0.41, AME–PME 0.68, ALE–PLE 0.46, clypeus height at AME 0.99, clypeus height at ALE 0.86.
Cheliceral furrow with three promarginal (+ one very small tooth, which is located most distally and is of one fourth the size of the most proximal one) and four retromarginal teeth.
Spination: Palp: 131, 110 (prolateral one less than half as long as dorsal one), 1101 (prolateral and ventral ones less than half as long as dorsal one); legs: femur I 566{556}, II 556{566}, III 545, IV 555{647}; patella I–IV 000; tibia I–II 3038, III 3033, IV 3033{3036}; metatarsus I–III 3035, IV 3034{2033}.
Measurements of palp and legs: Palp 8.7 [3.1, 1.4, 1.2, 3.0], I 52.7 [14.1, 3.5, 14.5, 14.3, 6.3], II 41.9 [11.7, 3.1, 10.7, 11.2, 5.2], III 30.1 [8.6, 2.6, 7.4, 7.5, 4.0], IV 43.6 [12.0, 2.8, 11.1, 12.0, 5.7]. Leg formula: 1423. FEMI+MTT-I/CL=3.74, thus legs short. In males of the himalayanus -group this value is usually higher (on average ca. 5).
Palpal femur without modification and straight (Fig. 7 D). Macrosetae ventrally on coxae of (at least) leg I, which are typical for males of the himalayanus -group, missing in the present male. Whether this is a specific character state or just some kind of malformation in this individual remains to be seen until more males of this species are available.
Copulatory organ (see also diagnosis above and general description for himalayanus -group in Bayer 2012): Cymbium distally narrow (Figs 7 A–C) and without dorsal scopula (Fig. 26 B); tegulum ca. 1.5 times longer than broad (Figs 8 B, 25B); conductor relatively long (Figs 8 A–C), distally with flange and arising in a 11 o’clock position on tegulum; embolus narrow, also in its basal section (Figs 8 B–C); sperm duct in ventral view diagonal Ushaped; subtegulum in ventral view hardly protruding from underneath tegulum (Fig. 8 B), but clearly visible in prolateral view (Fig. 8 A).
Female (measurements of holotype with those of paratypes given as range in parentheses):
Body and eye measurements: Carapace length 8.6 (6.2–8.4), maximal carapace width 6.1 (4.1–5.7), anterior width of carapace 3.8 (2.7–3.5), opisthosoma length 13.3 (8.8–11.5), opisthosoma width 7.0 (2.6–5.1). Eyes: AME 0.44 (0.31–0.43), ALE 0.55 (0.46–0.54), PME 0.56 (0.46–0.55), PLE 0.55 (0.45–0.54), AME–AME 0.25 (0.22–0.20), AME–ALE 0.09 (0.05–0.08), PME–PME 0.28 (0.24–0.26), PME–PLE 0.43 (0.37–0.39), AME–PME 0.78 (0.66–0.72), ALE–PLE 0.57 (0.45–0.51), clypeus height at AME 0.90 (0.73–1.19), clypeus height at ALE 0.86 (0.68–1.06).
Cheliceral furrow with three promarginal and four retromarginal teeth. Palpal claw with 16 (holotype) or 14 to 16 teeth.
Spination: Palp: 131 (131), 110 (110), 1101 (1101), 1014 (1014). Legs: femur I 556 (556, 566, 567), II 566{565} (556, 566, 657, 668), III 555 (555), IV 555 (555, 554); patella I–IV 0 0 0 (I–IV 000); tibia I 3038 (3038, 4039), II 3038 (3038), III 3034{3033} (3035, 3033), IV 3034 (3034); metatarsus I 3035 (3035, 3046), II 3035 (3035, 3036), III 3035 (3035), IV 3034 (3034).
Measurements of palp and legs: Palp 10.3 (7.9–9.9) [3.5 (2.6–3.3), 1.5 (1.1–1.4), 2.0 (1.4–1.9), 3.3 (2.8–3.2)], I 48.4 (37.7–49.5) [13.1 (10.1–13.5), 3.9 (2.5–3.7), 13.4 (10.3–14.0), 12.5 (9.9–12.6), 5.5 (4.9–5.7)], II 39.3 (30.6–39.1) [11.0 (8.5–11.1), 3.3 (2.3–3.2), 10.3 (8.1–10.4), 9.9 (7.8–9.9), 4.8 (3.9–4.5)], III 28.9 (22.2–28.3) [8.3 (6.4–8.4), 2.7 (1.8–2.6), 7.1 (5.5–6.9), 7.2 (5.6–7.0), 3.6 (2.9–3.4)], IV 40.8 (32.9–40.7) [11.2 (9.3–11.5), 3.0 (2.2–2.8), 10.4 (8.6–10.5), 11.0 (8.5–10.7), 5.2 (4.3–5.2)]. Leg formula: 1423 (1423). FEM-I+MTT-I/ CL=2.98–3.22, thus legs medium sized (to short) in relation to females of other species-groups. The legs range within the spectrum listed in Bayer (2012, p. 64) for females of the himalayanus -group.
Copulatory organ (see also diagnosis above and general description for himalayanus -group in Bayer 2012): Slits of median septum at anteriormost portion slightly onverging; copulatory openings slit-like and surrounded by semicircular, glossy, bulgy fields in the strongly sclerotised cuticle (Figs 10 A, 35D); muscle sigilla anterior to epigyne mostly almost as broad as long, number of slit sense organs in the area of epigynal field mostly four, and mostly located closely proximal to the muscle sigilla; epigynal field well developed and broader than long (Figs 9 A, 28D). Spermathecal bases slightly broader than long; spermathecal heads slightly longer than broad, located antero-medially at spermathecal bases (Figs 9 B, 10B, E, 31D). Course of internal duct system characterised by the long copulatory duct with its semicircular track (Fig. 9 C).
Colouration of male and female (see also description for himalayanus -group and Psechrus in Bayer 2012): Median bands on carapace serrated (in females more distinctly than in males), lateral bands narrow (ca. 0.5 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).
Intraspecific variation of female copulatory organs. In some specimens, the median septum is narrower (Fig. 10 A) or in very rare cases broader (Fig. 10 D) than usual (Fig. 9 A). The number of slit sense organs may be less than four (Fig. 10 D). The receptacula may be closer together (Fig. 10 B) or further apart (Fig. 10 E) from each other than usual. One receptaculum may be approximately as long as wide (Fig. 10 E). The internal duct course may vary in the section running through the receptaculum (Fig. 9 C cf. 10C).
Distribution. Vietnam (Fig. 34).
description: Published as part of Bayer, Steffen, 2014, Seven new species of Psechrus and additional taxonomic contributions to the knowledge of the spider family Psechridae (Araneae), pp. 1-54 in Zootaxa 3826 (1) on pages 16-19, DOI: 10.11646/zootaxa.3826.1.1, http://zenodo.org/record/286429