Male: Total length 7.19, carapace 4.19 long, 2.74 wide, opisthosoma 3.12 long, 2.05 wide. Eyes vestigial (Fig. 1A). Eye sizes and interdistances: AME absent, ALE 0.07, PME 0.06, PLE 0.09, PME–PME 0.16, PME–PLE 0.19, ALE–PME 0.16, ALE–PLE 0.07. Leg measurements: I 17.25 (4.30, 1.06, 4.53, 4.37, 2.99), II 15.98 (4.23, 1.03, 3.94, 4.10, 2.68), III 15.30 (3.96, 0.92, 3.58, 4.24, 2.60), IV 19.94 (4.85, 1.12, 4.80, 6.15, 3.02). Leg formula IV-I-II-III. Chelicerae with three promarginal and two retromarginal teeth (Fig. 1C). Opisthosoma and legs with long hairs (Fig. 2A–C).

Colouration (Fig. 2A–C). Carapace yellowish-brown, head region light brown, thoracic region pale yellow, fovea black. Chelicerae dark brown. Endites and labium brown, with white distal parts. Sternum yellowish-brown. Legs light brown. Opisthosoma and spinnerets grey.

Palp (Fig. 3). Patellar apophysis digitiform. Retrolateral tibial apophysis trapeziform, almost 2/3 the length of tibia, with its distal end slightly extending beyond the tibia. Lateral tibial apophysis short and rounded. Cymbium slender, more than twice as long as bulb; cymbial furrow almost 1/3 the length of cymbium. Median apophysis spoon-shaped, almost half the length of bulb. Conductor strong and sclerotised, curved ventrally, with weak basal lamellar and blunt end; dorsal apophysis of conductor triangular, distal tip with three denticles. Embolus filform and curved, arising from embolic base at 8:30 o’clock position.

Female: See Lin et al. (2024) (Fig. 1B, D, Fig. 2D–F and Fig. 4).

The male of T. doul can be distinguished from those of all other male-known congeners by the following combination of characters: 1. cymbium more than twice as long as bulb (less than twice as long as bulb in all other male-known congeners); 2. patella apophysis digitiform (pointed in T. tortus); 3. median apophysis large, almost half the length of bulb (almost 1/3 the length of bulb in all other male-known congeners); 4. conductor curved, with blunt distal end (straight and pointed in all other male-known congeners); 5. dorsal apophysis of conductor triangular and pointed (rounded and blunt in T. qixianensis and T. tortus, absent in T. liangensis and T. yumiganensis); 6. embolus arising from embolic base at 8:30 o’clock position (6 o’clock position in all other male-known congeners) (cf. Fig. 3 and figs. 5, 8, 10 and 12 in Li et al. (2019)).

The female of this species is similar to those of T. sinanensis Zhou & Zhao, 2023 in having wide copulatory opening, the posterior margin of atrium almost as wide as atrium and the epigynal teeth situated laterally on atrium (cf. Fig. 4 and figs. 3A–C in Zhou et al. (2023)), but can be distinguished by: 1. lateral part of copulatory duct with a projection (absent in T. sinanensis); and 2. spermatheca spherical, narrower than copulatory duct (oval and laterally elongated, wider than copulatory duct in T. sinanensis).

Known only from type locality (Shenlonggong Cave in Guangxi, China) (Fig. 5).