Genus Yaginumia Archer, 1960

Yaginumia Archer, 1960: 14.

Type species.

Aranea sia Strand, 1906 .

Diagnosis.

Yaginumia resembles Guizygiella and Zygiella in having a dorsoventrally flattened elliptical abdomen with almost symmetrical dorsal folium, and, in males, an enlarged paracymbium. It can be distinguished from Guizygiella by: 1) with triangular, toothed tegular projection (Figs 2 A – E, 4 A – E, 6 A – E) vs absent (Zhu et al. 2003: fig. 20 I, J); 2) tibia of pedipalp at least 1.5 × longer than wide in ventral view (Figs 2 C, 4 C, 6 C) vs about equal in length and width (Zhu et al. 2003: fig. 20 I); 3) epigyne with a scape (Figs 1 A – D, 3 A – D, 5 A – D) vs lacking (Zhu et al. 2003: fig. 20 F); and 4) abdomen bearing dense setae (Figs 1 E – J, 3 E – J, 5 E – J) vs sparse setae (Zhu et al. 2003: fig. 20 A). It differs from Zygiella by: 1) pedipalp of male with two patellar bristles (2 A, B, 4 A, B, 6 A, B) vs only one patellar bristle (Levi 1974: 271); 2) long axis of tegulum in “ horizontal ” position in ventral view (Figs 2 C, 4 C, 6 C) vs in “ vertical ” position (Levi 1974: figs 28, 29); 3) distance of PME – PLE is at least 3.6 × to that of PME – PME (Figs 1 E, H, 3 E, H, 5 E, H) vs posterior eyes almost equal separated (Levi 1974: figs 26, 57); 4) abdomen bearing dense setae (Figs 1 E – J, 3 E – J, 5 E – J) vs sparse setae (Levi 1974: fig. 26); and 5) web complete vs with a vacant sector.

Description.

Medium spiders with female total length of 4.25–13.10 and male total length of 3.15–8.20. Carapace pear-shaped, yellow to dark brown, darker in cephalic region than in thoracic region, fovea transverse. Endites wider than long. Labium triangular, swollen. Sternum cordiform. Legs yellow, always with dark annuli (except Y. medog sp. nov.). Abdomen elliptical, dorsum bearing dense setae, with dark median longitudinal folium. Ventral abdomen yellow to yellowish-gray with pale line on each side.

Pedipalp of male with two patellar bristles; tibia at least 1.5 × longer than wide; paracybium enlarged at base with small distal lobe; tegular projection almost triangular in ventral view, with toothed inner edge; median apophysis tapered distally; embolus short and slightly curved, almost totally covered by terminal apophysis; conductor membranous or weakly sclerotized; terminal apophysis prominent, weakly sclerotized, curved distally in ventral view.

Epigyne heavily sclerotized, wider than long in ventral view, with scape, the scape always torn off; copulatory openings situated on ventral surface; copulatory ducts twisted, about equal length to spermathecal diameter; spermathecae rounded, touching or nearly touching.

Composition.

Yaginumia medog Mi & Wang, sp. nov., Y. qiong Mi & Wang, sp. nov. and Y. sia (Strand, 1906) (type species).

Distribution.

East Asia (China, Japan, Korea).