Ischnothyreus linzhiensis Hu, 2001

Tong, Yanfeng, Bian, Dongju & Li, Shuqiang, 2023, Three new species of the genus Ischnothyreus Simon, 1893 and the discovery of the male of I. linzhiensis Hu, 2001 from Tibet, China (Araneae, Oonopidae), ZooKeys 1152, pp. 119-131 : 119

Ischnothyreus linzhiensis Hu, 2001

Figs 2A-L , 3A-I , 4A-C

Material examined.

7♂, 9♀ (SYNU-509-524): China, Tibet, Nyingchi, Pome County, Yigong Town , Kaduo Village , 30°07.515'N, 95°01.928'E; 2072 ± 3 m; 10.VIII.2013; Qi Cao leg.

Diagnosis.

This species is similar to I. serpentinum Saaristo, 2001 in the morphology of the winding duct and the size of the abdominal scuta, but can be distinguished by the large, snout-like structure of the endogyne (Fig. 3H, I ) vs. a small posterior process (see Richard et al. 2016: fig. 75E), and the conical apophysis of the male cheliceral anterior face and the flag-like sclerotized process of the fang base (Figs 2D-F , 4C ) vs. unmodified chelicerae (see Richard et al. 2016: fig. 70E).

Description.

Male (SYNU-509). Body: habitus as in Fig. 2A-C ; body length 1.64. Carapace: 0.88 long, 0.65 wide; yellow, oval in dorsal view, pars cephalica strongly elevated in lateral view, surface of elevated portion of pars cephalica smooth, sides finely reticulate, lateral margin straight, smooth (Fig. 2G ). Clypeus: straight in frontal view, ALE separated from edge of carapace by their diameter (Fig. 2I ). Eyes: ALE largest, ALE circular, PME squared, PLE oval; posterior eye row recurved from above; ALE touching, ALE-PLE touching (Fig. 2G, I ). Sternum: as long as wide, pale orange (Fig. 2H ). Mouthparts: chelicerae, endites and labium yellow; chelicerae straight, anterior face with conical apophysis, base of fangs with large flag-like sclerotized process, fang groove with a few small and one larger denticles (Figs 2D-F , 3C ); anteromedian tip of endites with one strong, tooth-like projection (Fig. 2H ). Abdomen: 0.76 long, 0.44 wide; dorsal scutum dark brown, covering 4/5 of abdomen width and approximately 5/6 of abdomen length, not fused to epigastric scutum; postgastric scutum covering ~ 2/3 of abdomen length. Legs: pale orange, femur I with two prolateral spines, tibia I with four pairs, metatarsus I with two pairs of long ventral spines. Leg II spination similar to leg I, except femur with only one prolateral spine. Legs III and IV spineless. Palp: trochanter with ventral projection; bulb with one ventral protuberance, distal end of bulb stout, with dorsal membrane, needle-like membrane and two leaf-like projections (Figs 2J-L , 4A, B ).

Female (SYNU-516). Same as male except as noted. Body: habitus as in Fig. 3A-C ; body length 1.76. Carapace: 0.72 long, 0.67 wide. Mouthparts: chelicerae and endites unmodified. Abdomen: 1.05 long, 0.67 wide; dorsal scutum very small; epigastric scutum well sclerotized, orange; postgastric scutum widely hexagonal, only around epigastric furrow. Endogyne: winding duct complex, strongly convoluted, ending in large, snout-like structure (Fig. 3H, I ).

Distribution.

China (Tibet: Nyingchi).

Figures

Figure 2. Ischnothyreus linzhiensis Hu, 2001, male A-C habitus in dorsal, ventral and lateral views D-F left chelicera, anterior, lateral and posterior views G-I prosoma, dorsal, ventral and anterior views J-L left palp, prolateral, dorsal and retrolateral views. Abbreviations: ca = conical apophysis; stp = strong, tooth-like projection; vp = ventral projection; vpr = ventral protuberance. Scale bars: 0.4 mm (A-C, G-I); 0.1 mm (D-F, J-L).

Figure 3. Ischnothyreus linzhiensis Hu, 2001, female A-C habitus in dorsal, ventral and lateral views D epigastric region, ventral view E-G prosoma, dorsal, ventral and anterior views H, I endogyne, ventral and dorsal views (cleared in lactic acid). Abbreviations: a = apodeme; sls = snout-like structure; wd = winding duct. Scale bars: 0.4 mm (A-C, E-G); 0.2 mm (D, H, I).

Figure 4. Ischnothyreus linzhiensis Hu, 2001, male A-C SEM; Ischnothyreus pome sp. nov., male holotype D-F SEM A, E left palp, prolateral view B, D distal end of bulb, prolateral view C, F left chelicerae, anterior and posterior views. Abbreviations: ca = conical apophysis; dm = dorsal membrane; flp = flag-like process; llp = leaf-like projection; nlm = needle-like membrane. Scale bars: 0.1 mm (A, C, E, F); 0.05 mm (B, D).