Bifidocoelotes quadratus sp. nov. (ḦNJȒDĦ)

Figures 6, 7

Type material. Holotype female (HNU606), China, Guangxi Zhuang Autonomous Region, Laibin City, Jinxiu Yao Autonomous County, Shengtang Mountain, 23°59.12'N, 110°8.23'E, 12 X, 2021, Ailan He, Jinxin Liu, Zongguang Huang, Xuemei Yang, Rongrong Liao, Yingli Wen, Zhao Ye, and Yang Liu leg.

Etymology. The specific epithet is a Latin adjective, referring to the shape of atrium.

Diagnosis. The female of this new species is different from those of all other Bifidocoelotes species (including the other two new species described in the present paper) by the extremely large atrium, while the atria of all other Bifidocoelotes species are smaller (Fig. 1B), usually reduced to a very small space (Fig. 1A, D) or a slit (Fig. 1C, E).

Description. Female: Total length 6.11, carapace 3.01 long, 1.84 wide, abdomen 2.90 long, 2.07 wide. Carapace pyriform, head region raised with broad anterior margin, thoracic region with yellowish lateral margins. Fovea brown, short, linear. Eye sizes and interdistances: AME 0.08, ALE 0.12, PME 0.12, PLE 0.13, AME–AME 0.04, AME–ALE 0.04, PME–PME 0.05, PME–PLE 0.13, ALE–PLE 0.07, AME–PME 0.11, ALE–ALE 0.34, PLE–PLE 0.59. MOA 0.34 long, anterior width 0.23, posterior width 0.33. Clypeus height 0.09. Chelicerae yellow-brown. Endite brown, longer than wide. Labium brown. Sternum yellow-brown, with sparse brown setae. Legs yellowbrown, with black annulations and some spines. Leg measurements: I 7.20 (2.00, 0.65, 1.73, 1.81, 1.01); II 5.05 (1.53, 0.48, 0.67, 1.60, 0.77); III 4.50 (1.62, 0.45, 0.96, 1.47, 1.08); IV 8.00 (2.20, 0.82, 1.68, 2.25, 1.05); leg formula IV, I, II, III. Abdomen oval, black dorsally, with five yellowish chevrons (Fig. 6A); yellowish ventrally, with scattered small dark patches. Spinnerets yellowish (Fig. 6B).

Epigyne (Fig. 6C, D): Atrium (At) extremely large, rectangular, located anteriorly. Epigynal tooth (ET) long, originating from the middle of anterior margin of epigyne, with a strongly bifurcated terminal part (left branch broken in the holotype). Spermatheca (Sp) consisted of two parts: anterior part bean-shaped, posterior part extended horizontally, forming distinct lobules (seems to be the result of left and right bases fused). Copulatory ducts (CD) long, strongly convoluted, situated between two bean-shaped parts of spermathecae. Spermathecal heads (SH) invisible in dorsal view, but visible in ventral view. Fertilization ducts (FD) long and membranous, far from each other .

Male. Unknown.

Distribution. Known only from the type locality in China (Guangxi) (Fig. 7).