Yunguirius trigonus Wei & Liu 2024, sp. nov.

Yunguirius trigonus Wei & Liu sp. nov. Figs 4, 5, 10 Type material. Holotype ♀ (HBU-WM-24-003): China: Chongqing City, Nanchuan District, Jinfo Mountain, 29.0489 ° N, 107.1279 ° E, elevation: 681 m, 30. IX. 2021, T. X. Gu leg. Etymology. The specific epithet is derived from the Greek word “ trigon ”, meaning triangular and referring to the atrium and the posterior epigynal sclerite of the new species forming into a subtriangular pattern; an adjective. Diagnosis. The females of Yunguirius trigonus sp. nov. resemble those of Y. subterebratus and Y. wangqiqiae sp. nov. in having a trapezoidal atrium, with the width longer than the length and the width at the widest point being three times longer than the narrowest point (Figs 4 A, 6 A; fig. 245 A in Zhu et al. 2017), compared to being trapezoidal but with the width being shorter than the length, and the width of the widest point approximately being twice that of the narrowest point in Y. ornatus (Fig. 3 A in Li et al. 2023), and being heart-shaped, pentagonal or subrounded in other Yunguirius species (Figs 1 A, 2 A, 8 A; figs 2 A, 4 A in Li et al. 2023). However, Y. trigonus sp. nov. can be distinguished from the latter by the following characteristics: 1) the presence of a pair of long and linear hoods (Fig. 4 A), versus having a pair of triangular hoods in the latter (Fig. 6 A; fig. 245 A in Zhu et al. 2017); 2) the short and slightly overlapping blind sacs of the copulatory ducts (Fig. 4 B), versus being long and obviously overlapped in the latter (Fig. 6 B; fig. 245 B in Zhu et al. 2017); 3) the spermathecal stalks are relatively short and thick (Fig. 4 B), versus being reduced in Y. subterebratus (fig. 245 B in Zhu et al. 2017) or being subequal to half the width of the atrium in Y. wangqiqiae Wei & Liu, sp. nov. (Fig. 6 B). Description. Female (holotype) (Fig. 5). Carapace reddish brown. Cervical and radial groove distinct. Cephalic region wide, moderately raised and wide, lateral margin with indistinct furrows. Chelicerae with 3 promarginal teeth and 2 retromarginal teeth, condyle red. Sternum longer than wide. Abdomen pale yellow, covered by hairs. Legs red. Total length 12.31. Carapace 5.83 long, 3.99 wide, cephalic region 3.49 wide. Abdomen 6.48 long, 3.68 wide. Eye size and interdistance: AME 0.18, ALE 0.27, PME 0.22, PLE 0.25; AME – AME 0.10, AME – ALE 0.17, AME – PME 0.16, ALE – PLE 0.10, PME – PME 0.11, PME – PLE 0.42. Leg measurements: Leg I 16.00 (2.12, 0.81, 3.97, 1.71, 3.39, 2.86, 1.57), leg II 14.71 (1.82, 0.82, 3.61, 1.66, 2.68, 2.74, 1.65), leg III 12.33 (1.55, 0.80, 2.99, 1.41, 1.94, 2.35, 1.45), leg IV 16.90 (1.87, 0.93, 4.13, 1.82, 3.41, 3.33, 1.61). Epigyne (Fig. 4). Epigynal teeth absent. Atrium centrally situated, trapezoidal, anterior margin incomplete, posterior margin short. Epigynal sclerite longer than wide. Hoods long, vertically oriented, situated laterally. Fold absent. Copulatory ducts broad, laterally originated, blind sacs short, distal tips slightly overlapped. Spermathecal bases normal, spermathecal stalks extended laterally, with distal tips conch-shaped, spermathecal heads reduced and membranous, distal tips visible. Fertilization ducts posteriorly situated. Male. Unknown. Distribution. China (Chongqing).