Atypus tibetensis, Zhu & Zhang & Song & Qu, 2006

Zhu, Ming-Sheng, Zhang, Feng, Song, Daxiang & Qu, Ping, 2006, A revision of the genus Atypus in China (Araneae: Atypidae), Zootaxa 1118, pp. 1-42 : 31-34

Atypus tibetensis sp. nov.

( Figs 99–110 )

Type material. Holotype male, paratypes 13 females, CHINA: Xizang (Tibet), Zayü County, 28°36’N, 97°24’, E Xiazayü Town , 8 August 2002, M. S. Zhu, F. Zhang, J. X. Zhang and Z. S. Zhang leg. ( MHBU).

Diagnosis. The new species resembles A. heterothecus in its narrow, strongly recurved and chevron­shaped fovea, but differs in that males possess a longer conductor with its upper corner far away from the tegular process ( Figs 109–110 ); females differ by the pyriform median pair of receptacula with relatively longer and thicker basal stalks ( Figs 102–105 ); both sexes by their almost top­shaped fourth pair of sternal sigilla ( Figs 101, 107 ).

Etymology. The specific name refers to the type locality.

Description.

Male (holotype). Total length (including chelicerae) 8.37. Carapace 2.79 long, 2.63 wide; abdomen 3.33 long, 2.25 wide. Carapace as in A. heterothecus , but yellow brown, pars cephalica with more dark stripes. Eye region occupying more than one­third of width of pars cephalica. Both eye rows recurved, posterior eye row slightly wider than anterior one. Eye diameters: AME 0.20, ALE 0.20, PME 0.18, PLE 0.18. Distances AME–AME 0.15, AME–ALE 0.05, PME–PME 0.50, PME–PLE 0. MOA 0.38 long, front width 0.55, back width 0.73. Fovea narrow, strongly recurved and chevron­shaped, occupying about 1/ 10 of carapace width at that point. Chelicerae light yellow brown, with 11 teeth on promargin and granular texture on pro­ and retrolateral faces. Anterior lobe of pedipalp coxa yellow brown, inner margin with two irregular rows of small cuspules. Sternum yellow brown, with black border, 2.04 long and 2.00 wide. First and second pairs of sigilla almost equal in size, fourth pair almost top­shaped.

Abdomen black brown, with dorsal scutum purple black brown. ALS 0.30 long, PMS 0.55 long, PLS 1.76 long (basal joint 0.38, median 0.50, subapical 0.44, apical 0.44).

Palpal femur without furrow. Legs yellow brown, with short and thin brown hairs and few spines. Only femur I with granular texture. Metatarsus IV lacking dorsal spine. Leg formula: 4123.

Male palp ( Figs 108–110 ): conductor long, narrow at base, upper distal corner far from tegular process and distinctly folded downwards.

Female. Total length (including chelicerae) 19.89. Carapace 6.66 long, 5.49 wide; abdomen 9.00 long, 6.66 wide. Carapace blackish brown, similar to that of male. Eye region black, occupying nearly one­third of width of pars cephalica. Eye diameters: AME 0.31, ALE 0.27, PME 0.24, PLE 0.24. AME–AME 0.34, AME–ALE 0.20, PME–PME 1.02, PME–PLE 0.03. MOA 0.61 long, front width 0.96, back width 1.39. Fovea as that of male. Chelicerae black brown, with 12 teeth on promargin. Anterior lobe of pedipalp coxa red brown, inner margins and inner half of ventral surface with lots of cuspules. Sternum longer than wide, reddish brown, with paler border. Sigilla as in male.

Abdomen dark red brown, with dorsal tergite pale orange. ALS 0.65 long, PMS 1.36 long, PLS 3.44 long (basal joint 0.78, median 1.09, subapical 0.99, apical 0.58).

Legs blackish brown. Metatarsus IV with seven dorsal spines. Leg formula: 1423.

Vulva ( Figs 102–105 ): atrium short, all four receptacula almost equal in size, with long and thick basal stalks.

Variation. Size range of mature females: carapace length 5.13–6.66, width 4.32–5.49, total length 14.76–18.98, n=13.

Habitat. Found in pursewebs attached to the base of a rock.

Distribution. China: Tibet.

Figures

FIGURES 99–110. Atypus tibetensis sp. nov., 99–105, female paratypes. 99, carapace, dorsal view; 100, left chelicera, inner­lateral view; 101, labium and sternum, ventral view; 102–105, vulvae, dorsal view (from Zayü, Xizang). 106–110, male holotype. 106, left chelicera, inner­lateral view; 107, labium and sternum, ventral view; 108, left palp, prolateral view (from Zayü, Xizang); 109, left palpal bulb, prolateral view; 110, same, retrolateral view. Scale bars: 99–101, 106–107, 1.0mm; 102–105, 108–110, 0.2mm.