Sinostidia shuangjiao Yu & Li sp. nov.

Figs 21, 22

Type material.

Holotype: ♂ (IZCAS-Ar34738), China: Yunnan: Xishuangbanna: Mengla County: Menglun Town: Menglun Nature Reserve: Anogeissus acuminata plantation (~ 20 years old) (21°53.993'N, 101°16.810'E, 610 m), 19 August 2007, G. Zheng leg. Paratype: 1♀ (IZCAS-Ar34739, YHCLU0155), G213 roadside, Leprosy village (21°53.590'N, 101°17.296'E, 540 m), 4 May 2019, H. Yu leg.

Other material examined.

1♂ (YHCLU0151), same data as the paratype .

Etymology.

The specific name is derived from the Chinese pinyin shuâng ji ǎ o, meaning two-horned, referring to the forked tegular apophysis; noun in apposition.

Diagnosis.

Sinostidia shuangjiao sp. nov. closely resembles S. dujiao sp. nov. (Figs 23, 24) but can be distinguished by the shape of the copulatory organs. Males of the new species differ from those of S. dujiao sp. nov. by: (1) the bifid tip of the tegular apophysis represented by two tooth-shaped apophyses (vs. not bifid) (cf. Figs 21A-E and 23C-E); (2) the filiform or claw-shaped embolic tip (vs. large and conical, cf. Figs 21B-E and 23B-E); (3) the conductor is transparent and membranous (vs. thick and partly membranous) (cf. Figs 21D, E and 23D, E). The female of the new species can be differentiated from S. dujiao sp. nov. by lacking an atrium (vs. atrium present) (cf. Figs 22A, B and 24A, B), the copulatory openings located laterally on the epigynal plate (vs. located at anterior atrial border) (cf. Figs 22A, B and 24A, B), and by the globular bursae which are smaller than the spermathecae (vs. reniform burse distinctly larger than the spermathecae) (cf. Figs 22C, D and 24C, D).

Description.

Male (holotype) (Fig. 22E, F). Total length 4.73; carapace 1.75 long, 1.49 wide; opisthosoma 2.98 long, 1.16 wide. Carapace pyriform, ocular region distinctly narrowed; light orange, slightly darker frontally, without distinct pattern; fovea reddish. Eyes: AER slightly recurved, PER slightly wider than AER and procurved in dorsal view. AME dark, other eyes light; with black rings. Eye sizes and interdistances: AME 0.09, ALE 0.09, PME 0.12, PLE 0.11, AME-AME 0.03, AME-ALE 0.02, PME-PME 0.14, PME-PLE 0.08, MOQL 0.32, MOQA 0.28, MOQP 0.41. Chelicerae red-brown. Labium and endites light orange. Sternum yellowish white. Legs yellowish orange. Leg measurements: I 7.05 (1.95, 2.91, 1.43, 0.77), II 6.61 (1.86, 2.1, 1.44, 0.70), III 5.27 (1.55, 1.72, 1.44, 0.56), IV 7.67 (2.12, 2.59, 2.23, 0.73). Abdomen (Fig. 22E, F) lanceolate, dorsum with numerous inconspicuous patches; venter white; all spinnerets without distinct markings.

Palp (Fig. 21A-E): Retrolateral tibial apophysis claw-shaped, retrolaterally pointed, ~ 1/2 of tibia length, with curved, sharp apex; ventral tibial apophysis pointed anteriorly, thumb-like, ~ 1/3 of tibia length. Bulb oval, ~ 2 × longer than wide, sperm duct indistinct in ventral view. Tegular apophysis large, as long as tegulum width, originating retrolaterally on tegulum, with bifurcated distally, covering embolic base. Embolus claw-shaped, tip extended to apex of cymbium, directed antero-prolaterally; embolic base as long as free (filamentous) part of embolus, represented by enlarged tubercle located prolaterally (~ 10 o’clock relative to tegulum). Conductor membranous, ~ 1/2 embolus length, originating distally on tegulum, base wide, apex narrowed, folded.

Female (paratype IZCAS-Ar34739). Total length 5.60; carapace 2.36 long, 1.74 wide; opisthosoma 3.21 long, 1.54 wide. General characters as in males, but slightly larger and lighter (Fig. 22G, H). Eye sizes and interdistances: AME 0.11, ALE 0.13, PME 0.13, PLE 0.09, AME-AME 0.06, AME-ALE 0.05, PME-PME 0.21, PME-PLE 0.11, MOQL 0.34, MOQA 0.36, MOQP 0.52. Legs uniformly white. Leg measurements: I 6.97 (1.97, 2.85, 1.38, 0.77), II 6.16 (1.70, 2.43, 1.34, 0.69), III 5.41 (1.66, 1.71, 1.50, 0.53), IV 7.97 (2.01, 2.80, 2.22, 0.95).

Epigyne (Fig. 22A-D): Plate distinctly wider than long, with shallow depression located anteriorly. Depression broad, width almost equal to the plate width, ellipsoid, ~ 1.6 × wider than long; bounded by numerous, relatively long setae, sparse anteriorly, dense posteriorly and laterally. Copulatory openings small but distinct, located laterally in depression, separated by ~ 15 diameters, leading to short copulatory ducts which descend obliquely to spermathecae. Spermathecae consisting of twisted base and globular head; spermathecal heads separated by 2/3 of their diameter. Bursae globular, close together, translucent. Fertilisation ducts indistinct.

Distribution.

Known only from the type locality.