Bifurcia shuangqiao, Yang & Li & Yao, 2024

Yang, Lan, Li, Shuqiang & Yao, Zhiyuan, 2024, Five new species of the spider genus Bifurcia Saaristo, Tu & Li, 2006 (Araneae, Linyphiidae) from Sichuan, China, Zoosystematics and Evolution 100 (2), pp. 705-720 : 705-720

Bifurcia shuangqiao sp. nov.

Figs 10 , 11 , 12 , 16 G, I

Type material.

Holotype ♂ ( IZCAS - Ar 44932 ) and paratype 1 ♀ ( IZCAS - Ar 44933 ), Shuangqiaogou (31 ° 7.34 ' N, 102 ° 46.71 ' E), Siguniangshan National Scenic Area , Siguniangshan Town, Xiaojin County, Aba Tibetan and Qiang Autonomous Prefecture, Sichuan, China, 02 / 08 / 2004, Lihong Tu leg.

Etymology.

The specific name refers to the type locality; noun in apposition.

Diagnosis.

The new species resembles B. curvata (Sha & Zhu, 1987) ( Saaristo et al. 2006: figs 9–17) with similar large chitinized basal part of median membrane ( CPM) and epigyne (Figs 10 B , 11 A , 16 G, I ), but can be distinguished by embolus with hooked apex ( AX) (Fig. 16 G vs. sharp, Saaristo et al. 2006: fig. 12), by anterior terminal apophysis ( ATA) finger-shaped (Figs 10 A , 16 G vs. handle-shaped, Saaristo et al. 2006: figs 11, 12), by lamellar extension of pseudolamella ( LE) absent (Figs 10 C , 16 G vs. present and ribbon-shaped, Saaristo et al. 2006: figs 10, 12), and by posterior part of posterior median plate ( PMP) straight (Fig. 11 C vs. curved, Saaristo et al. 2006: fig. 17).

Description.

Male (holotype). Total length: 1.78, carapace 0.88 long, 0.78 wide, abdomen 0.89 long, 0.62 wide. Eye inter-distances and diameters: AME 0.05, AME-AME 0.02, ALE 0.08, AME-ALE 0.06, PME 0.08, PME-PME 0.04, PLE 0.08, and PME-PLE 0.04. Sternum 0.53 long, 0.51 wide. Clypeus 0.12 high. Chelicerae promargin with 3 teeth, retromargin with 4 teeth. Length of legs: I 5.43 (1.41, 0.28, 1.48, 1.34, 0.92), II 4.63 (1.24, 0.26, 1.21, 1.14, 0.78), III 3.42 (0.97, 0.22, 0.80, 0.83, 0.60), IV 4.47 (1.33, 0.25, 1.13, 1.06, 0.70). Leg formula: I-II-IV-III. TmI 0.15, TmIV absent. Tibial spine formula: 2-2 - 2 - 2. Carapace yellowish-brown. Sternum dark brown. Abdomen with greenish gray dorsal spots (Fig. 12 A, B ).

Palp (Fig. 10 ). Patella with long dorsal bristle. Tibia unmodified. Cymbium with hook-shaped proximal apophysis ( PCA) pointing retrolaterally. Paracymbium (P) bifurcate with three branches: proximally short branch, medianly robust branch with round lateral branch and distal branch. Pit hook ( PH) on stout distal part of suprategulum ( SPT) extremely reduced to small outgrowth. Embolic division (Fig. 16 G, I ): anterior part of radix ( APR) hook-shaped; sperm duct inside the radix ( R) inconspicuous with Fickert’s gland ( FG); pseudolamella ( PL) strongly sclerotized and lamellar extension ( LE) absent. Anterior terminal apophysis ( ATA) extending out handle-shaped tip pointing anterodorsally; median terminal apophysis ( MTA) membranous with serrated margin; posterior terminal apophysis ( PTA) rectangular and strongly sclerotized. Embolus (E) with conical embolus proper ( EP), sclerotized thumb (TH), and hooked apex ( AX). Median membrane ( MM) with large chitinized basal part ( CPM).

Female (paratype). Total length: 1.86, carapace 0.95 long, 0.80 wide, abdomen 0.94 long, 1.33 wide. Eye inter-distances and diameters: AME 0.04, AME-AME 0.02, ALE 0.09, AME-ALE 0.05, PME 0.08, PME-PME 0.05, PLE 0.08, and PME-PLE 0.04. Sternum 0.60 long, 0.56 wide. Clypeus 0.10 high. Chelicerae promargin with 3 teeth, retromargin with 5 teeth. Length of legs: I 5.37 (1.48, 0.33, 1.44, 1.28, 0.84), II 4.79 (1.33, 0.31, 1.22, 1.13, 0.80), III 3.70 (1.10, 0.26, 0.88, 0.86, 0.60), IV 4.69 (1.42, 0.27, 1.19, 1.11, 0.70). Leg formula: I-II-IV-III. TmI 0.17, TmIV absent. Tibial spine formula: 2-2 - 2 - 2. Coloration generally as in male (Fig. 12 C, D ).

Epigyne (Fig. 11 ). Basal part of scape ( BS) sparsely clothed with long curved hairs, turned under basal part forming large circle. Posterior part of posterior median plate ( PMP) curved. Distal part of scape ( DPS) T-shaped, laterally directed lateral lobes (LL) extending out of either side in ventral view. Spermathecae (S) S-shaped.

Distribution.

China (Sichuan, type locality; Fig. 1 ).

Figures

Figure 1. Distribution of the new Bifurcia species from Sichuan, China: 1. B. kangding sp. nov.; 2. B. labahe sp. nov.; 3. B. luding sp. nov.; 4. B. shuangqiao sp. nov.; 5. B. xiaojin sp. nov.

Figure 10. Bifurcia shuangqiao sp. nov., holotype male palp: A. Prolateral view; B. Retrolateral view; C. Ventral view; D. Dorsal view. Scale bars: 0.10 mm (A – D).

Figure 11. Bifurcia shuangqiao sp. nov., paratype female epigyne: A. Ventral view; B. Lateral view; C. Dorsal view. Scale bar: 0.10 mm (A – C).

Figure 12. Bifurcia shuangqiao sp. nov., holotype male (A, B) and paratype female (C, D) habitus: A, C. Dorsal view; B, D. Ventral view. Scale bars: 0.50 mm (A – D).

Figure 16. Bifurcia spp., embolic division: A, D. B. kangding sp. nov.; B, E. B. labahe sp. nov.; C, F. B. luding sp. nov.; G, I. B. shuangqiao sp. nov.; H, J. B. xiaojin sp. nov.; A – C, G, H. Prolateral view; D – F, I, J. Retrolateral view. Scale bars: 0.10 mm (A – J).