Material examined. Holotype ♂ (IZCAS), Vietnam, Ninh Binh Province, Cuc Phuong National Park, on the path to the Old Tree, 20.VIII.2015 (20º20.972′N, 105º35.600′E), elev. 437 m, leg. Q. Zhao, Y. Li & Z. Chen. Paratype 1♀ (IZCAS), same data as holotype.
Etymology. The specific name is derived from the type locality; noun.
Diagnosis. The new species is similar to S. bulbiformis Lin, Pham & Li, 2009, but males can be distinguished by the laterally excavated chelicerae with a horn-like apophysis (Figs 55H–I) and by the nearly spherical male palpal bulb (Figs 18A–B), and females by the very long, curved afferent spermathecae (Fig. 19B). S. bulbiformis males have unmodified chelicerae, a more flattened palpal bulb, and females have very short, nearly straight afferent spermathecae (Lin et al., 2009: figs 3–4).
Description. Male. Total length 1.13; carapace length 0.51; carapace width 0.44; abdomen length 0.57; abdomen width 0.40. Prosoma: carapace pyriform, narrowing gradually anteriorly; light yellow, suffused with purplish pattern (Fig. 18C); pars cephalica flat; fovea not visible. Sternum light yellow, suffused with purplish color, as long as wide. Endites light yellow with serrula; labium light yellow. Clypeus nearly vertical; short. Chelicerae light yellow; external margin strongly excavated, anterior face with one horn-like apophysis; promargin with a series of six teeth reaching the lamina; retromargin with two very small denticles (Figs 55H–I). Eyes: six contiguous eyes surrounded by black pigmentation, PME smallest, PLE largest (Fig. 18C). Opisthosoma oval; light gray. Legs light yellow; leg lengths I, II missing; III 1.56 (0.42, 0.14, 0.43, 0.32, 0.25); IV 2.16 (0.60, 0.16, 0.63, 0.45, 0.32). Genitalia (Fig. 18). Palpal femur long; palpal tibia as long as cymbium (Figs 18A–B). Cymbium conical, with a prolateral extension basally. Bulb spherical, as long as wide. Embolus short, black, associated sclerites absent; sperm duct initially wide, gradually narrowing distally (Fig. 18D).
Female. Total length 1.41; carapace length 0.57; carapace width 0.46; abdomen length 0.80; abdomen width 0.58. Similar to male in color and general features (Figs 19D–E) but larger. Chelicerae unmodified. Legs light yellow; leg lengths I 1.85 (0.50, 0.16, 0.52, 0.37, 0.29); II missing; III 1.64 (0.45, 0.15, 0.43, 0.47, 0.34); IV 2.22 (0.40, 0.13, 0.30, 0.29, 0.23). Genitalia. Internal genitalia with afferent spermathecae elongated, curved, extending past the sides of the abdomen (Fig. 19B); spermathecae oval (Fig. 19A).
Distribution. Known only from the type locality.