Trilacuna rastrum Tong & Li, 2007 from Yunnan, China.

See Tong et al. (2020).

Fifty-one species, including three described here.

From Iran to the Korean Peninsula and south to Sumatra, Indonesia.

China • 1♂1♀ (SYNU-916–917); Xizang, Nyingchi City, N of Bayi Town; 29°38.24'N, 94°22.19'E, 2900 m elev.; 10.VII.2013; L. Lin leg. • 2♂2♀ (SYNU-918–921); S of Mainling Co.; 29°12.316'N, 94°12.649'E, 3060 m elev.; 13.VIII.2013; Q. Cao leg. • 1♂1♀ (SYNU-922–923); Mainling Co., Nanyi Town, Zhagonggou Scenic Area; 29°09.315'N, 94°12.869'E, 3153 m elev.; 28.VII.2012; Z. Yao & Z. Zhao leg.

China • 2♂ (SYNU-F-933–934); Nyingchi City, N of Bayi Town; 29°38.24'N, 94°22.19'E, 2900 m elev.; 10.VII.2013; L. Lin leg. • 1♂ (SYNU-F-937); same data as above • 2♂ (SYNU-F-935–936); Bayi Town; 29°39.831'N, 94°20.669'E, 2990 m elev.; 12.VII.2013; L. Lin leg. • 1♀ (SYNU-F-938); Mainling Co.; 29°22.068'N, 94°24.663'E, 2965 m elev.; 11.VIII.2014; L. Lin leg. • 2♂1♀ (SYNU-F-939–941); S of Mainling Co.; 29°12.316'N, 94°12.649'E, 3060 m elev.; 13.VIII.2013; L. Lin leg. • 1♀ (SYNU-F-942); Mainling Co., Nanyi Town, Zhagonggou Scenic Area; 29°09.315'N, 94°12.869'E, 3153 m elev.; 28.VII.2012; Z. Yao & Z. Zhao leg. • 2♂ (SYNU-F-943–944); N of Mainling Co.; 29°13.310'N, 94°13.309'E, 3050 m elev.; 13.VIII.2013; Q. Cao leg. • 1♀ (SYNU-F-945); same data as above • 3♂3♀ (SYNU-F-948–953); Bomi Co., Zhamo Rd., nr Baqiong Vill.; 29°52.194'N, 95°43.505'E, 2880 m elev.; 19.VII.2013; L. Lin leg. • 1♂ (SYNU-F-954); Mainling Co.; 3.VII.1997; M. Wu leg.

See Grismado et al. (2014).

Male epigastric area with a patch of enlarged setae in the specimens from India (Grismado et al. 2014: figs 47A, B, 51B), but the setae are in a regular row in the specimens from Xizang, China (Fig. 2C, G).

Figure 2. 

Trilacuna bangla Grismado & Ramírez, 2014, male A, C, E habitus, dorsal, ventral and lateral views B, D, F, H prosoma, dorsal, ventral, lateral and anterior views G abdomen, ventral view, arrow shows the row of setae. Scale bars: 0.4 mm.

Figure 3. 

Trilacuna bangla Grismado & Ramírez, 2014, male left palp A–C (light) and D–K (SEM) A, D prolateral view B, E dorsal view C, F retrolateral view G bulb, prolateral view H bulb, retrolateral view I, J, K distal part of bulb, prolateral, dorsal and retrolateral views. Scale bars: 0.1 mm (A–G); 0.05 mm (I–K).

Figure 4. 

Trilacuna bangla Grismado & Ramírez, 2014, female A, C, E habitus, dorsal, ventral and lateral views B, D, F, H prosoma, dorsal, ventral, lateral and anterior views G abdomen, ventral view. Scale bars: 0.4 mm.

China (Xizang), India (West Bengal), Nepal (Fig. 1).

Holotype China • ♂ (SYNU-914); Xizang, N of Mainling Co.; 29°13.310'N, 94°13.309'E, 3050 m elev.; 13.VIII.2013; Q. Cao leg. Paratype. China • 1♀ (SYNU-915); same data as holotype.

The specific name is a noun in apposition taken from the type locality.

The new species is similar to T. bangla in the shape of the bulb but can be distinguished by the male epigastric region with a small wedge-shaped process (Fig. 5D, arrow) vs. lacking, but with a row of enlarged setae (Fig. 2G, arrow); the psembolus with serrated structure at the base (Fig. 6M, arrow) vs. lacking, instead of cluster of fibers (Fig. 3I); the reticulated abdominal scutum of the female (Fig. 7A, C, E) vs. smooth (Fig. 4A, C, E); and the very small globular structure of the endogyne (Fig. 14B) vs. very large (Fig. 14F).

Figure 5. 

Trilacuna mainling sp. nov., male holotype (A–H), Trilacuna metok sp. nov. (I), Trilacuna bangla (J), Trilacuna zayu sp. nov. (K) A, C, E, G prosoma, dorsal, ventral, lateral and anterior views B, D, F abdomen, dorsal, ventral and lateral views, arrow shows the small wedge-shaped process H–K endites, ventral view. Scale bars: 0.4 mm.

Figure 6. 

Trilacuna mainling sp. nov., male left palp A–F (light) and G–N (SEM) A, G prolateral view B, H dorsal view C, I retrolateral view D, M distal part of bulb, prolateral view, arrow shows the serrated structure E, K distal part of bulb, dorsal view F, N distal part of bulb, retrolateral view J, L bulb, prolateral and retrolateral views. Scale bars: 0.1 mm (A–C, G–J, L); 0.05 mm (D–F, K, M, N).

Figure 7. 

Trilacuna mainling sp. nov., female paratype A, C, E habitus, dorsal, ventral and lateral views B, D, F, H prosoma, dorsal, ventral, lateral and anterior views G abdomen, ventral view. Scale bars: 0.4 mm.

Male. Body: yellow, legs lighter; habitus as in Fig. 5A–F; body length 1.59. Carapace (Fig. 5A, E): 0.87 long, 0.72 wide; sides granulate. Eyes (Fig. 5A, G): well developed; ALE separated from edge of carapace by one diameter. Mouthparts (Fig. 5C, G, H): endites slender, distally not branched. Sternum (Fig. 5C): surface reticulated. Abdomen: 0.63 long, 0.48 wide; sperm pore situated at level of anterior spiracles; apodemes present, posterior spiracles connected by groove; with small wedge-shaped process situated between anterior and posterior spiracles; epigastric region slightly elevated (Fig. 5D, F). Palp (Fig. 6A–N): orange; 0.68 long (0.21, 0.12, 0.11, 0.24); femur not enlarged (width/length = 0.46); bulb triangle; psembolus with several rows of serrated structure at base, psembolus proper surrounded by numerous fiber structures.

Female (paratype, SYNU-915). As in male except as noted. Body: habitus as in Fig. 7A, C, E; body length 2.19. Carapace: 0.97 long, 0.79 wide; Abdomen: 1.37 long, 0.74 wide; dorsal and ventral scutum surface reticulated. Epigastric area (Figs 7G, 14A): with recurved, strongly sclerotized arches (sar). Endogyne (Fig. 14B): with narrow, transverse sclerite (tsc); with anterior large T-shaped sclerite (as) and posterior small globular structure (glo); transverse bars (tba) with pair of lateral apodemes (ap).

Known only from the type locality (Fig. 1).

Holotype China • ♂ (SYNU-911), Xizang, Nyingchi City, Metok Co., nr Yadong Vill.; 29°20.605'N, 95°20.807'E, 1360 m elev.; 6.VIII.2013; L. Lin leg. Paratypes. China • 1♂1♀ (SYNU-912–913); same data as holotype • 1♀ (SYNU-924); same data as holotype.

China • 1♂1♀ (SYNU-F-955–956); same data as holotype • 1♀ (SYNU-F-967); same data as holotype • 1♂2♀ (SYNU-F-976–978); same data as holotype • 1♀ (SYNU-F-963); near Metok Co.; 29°19.399'N, 95°20.448'E, 1300 m elev.; 3.VIII.2013; L. Lin leg. • 1♂1♀ (SYNU-F-973–974); same data as above • 1♂2♀ (SYNU-F-964–966); near Metok Co.; 29°19.382'N, 95°19.016'E, 980 m elev.; 2.VIII.2013; L. Lin leg. • 1♂2♀ (SYNU-F-957–959); Metok Co., hills nr Nongjiale; 29°19.087'N, 95°18.876'E, 1280 m elev.; 4.VIII.2013; Q. Cao leg. • 3♂ (SYNU-F-960–962); same data as above • 1♀ (SYNU-F-968); same data as above • 1♀ (SYNU-F-975); same data as above • 4♂ (SYNU-F-969–972); 108 km along highway from Bomi Co. to Metok Co.; 29°29.178'N, 95°26.868E, 1360 m elev.; 9.VIII.2013; L. Lin leg.

The specific name is a noun in apposition taken from the type locality.

Males of this new species are similar to those of T. triseta Tong & Li, 2000 in the branches of psembolus, but can be distinguished by the fused cymbium and bulb (Fig. 9A–N) vs. cymbium well separated (Tong et al. 2020: fig. 12A, B) and the coxae IV connected by radial furrow (Fig. 8D) vs. not connected (Tong et al. 2020: fig. 11F). Females of the new species can be distinguished from all congeners by the long, narrow posterior spiracles, which are situated at the anterior corner of the postgastric scutum (Fig. 10C, E) vs. normal size, far away the anterior corner (e.g., Figs 4G, 7G, 13G).

Figure 8. 

Trilacuna metok sp. nov., male holotype A, C, E habitus, dorsal, ventral and lateral views B, D, F, H prosoma, dorsal, ventral, lateral and anterior views G abdomen, ventral view. Abbreviation: cmp = clypeus median projection. Scale bars: 0.4 mm.

Figure 9. 

Trilacuna metok sp. nov., male left palp A–F (light) and G–N (SEM) A, G prolatral view B, I retrolateral view C, H dorsal view D, L distal part of cymbiobulb, prolateral view E, M distal part of cymbiobulb, dorsal views F, N distal part of cymbiobulb, retrolateral view J, K cymbiobulb, prolateral and retrolateral views. Abbreviations: ab = anterior branch; bdb = broad dorsal branch; pb = posterior branch; sdb = slender dorsal branch. Scale bars: 0.1 mm (A–K); 0.05 mm (L–N).

Figure 10. 

Trilacuna metok sp. nov., female paratype A, C, E habitus, dorsal, ventral and lateral views B, D, F, H prosoma, dorsal, ventral, lateral and anterior views G abdomen, ventral view. Abbreviations: cmp = clypeus median projection; psp = posterior spiracles. Scale bars: 0.4 mm.

Male. Body: reddish-brown, legs yellow; habitus as in Fig. 8A, C, E; body length 1.61. Carapace (Fig. 8B, F): 0.81 long, 0.63 wide; sides smooth. Eyes (Fig. 8B, H): eyes well developed; ALE separated from edge of carapace by 1.25 diameters. Mouthparts (Figs 8D, H, 5I): labium distally not branched, with large membranous area at anterior part. Sternum (Fig. 8D): surface smooth, with large seta pits; with radial furrows between coxae I–II, II–III, III–IV and IV–IV. Abdomen (Fig. 8G): 0.87 long, 0.55 wide; surface smooth; sperm pore situated between anterior and posterior spiracles; apodemes present, posterior spiracles connected by groove. Palp (Fig. 9A–N): orange; 0.58 long (0.16, 0.13, 0.08, 0.21); femur elongated (width/length = 0.48); bulb and cymbium fused; psembolus including slender anterior branch (ab), slender dorsal branch (sdb), broad dorsal branch (bdb), and slender posterior branch (pb).

Female (paratype, SYNU-913). As in male except as noted. Body: habitus as in Fig. 10A, C, E; body length 2.19. Carapace: 0.97 long, 0.79 wide. Abdomen: 1.37 long, 0.74 wide; posterior spiracles narrow and long (psp), situated at anterior corner of postgastric scutum. Epigastric area (Figs 10G, 14C): without recurved, strongly sclerotized arches. Endogyne (Fig. 14D): with narrow, transverse sclerite (tsc); with an anterior large T-shaped sclerite (as) and a posterior small globular structure (glo); transverse bars (tba) with pair of strongly curved, thick lateral apodemes (ap).

All the known species of the genus Trilacuna have a well-separated cymbium and bulb; the fused cymbium and bulb demonstrate that T. metok sp. nov. is quite different from all other species of Trilacuna. But based on the psembolus and somatic characters, e.g., the deeply incised labium and the large setae base on the male chelicerae, it is reasonable to consider this species in Trilacuna.

Known only from the type locality (Fig. 1).

Holotype China • ♂ (SYNU-908); Xizang, Nyingchi City, Zayu Co., Gaba Oil Field; 28°38.849'N, 97°27.088'E, 2300 m elev.; 25.VII.2013; Q. Cao leg. Paratypes. China • 1♂ (SYNU-F-928); same data as holotype • 2♀ (SYNU-909–910); Zayu Co., Dongriqugou; 28°39.670'N, 97°28.657'E, 2470 m elev.; 23.VII.2013; L. Lin leg.

China • 1♂ (SYNU-F-929); Zayu Co., Dongriqugou; 28°39.670'N, 97°28.657'E, 2470 m elev.; 23.VII.2013; Q. Cao leg. • 2♀ (SYNU-F-931–932); same data as above • 1♀ (SYNU-F-930); Zayu Co., Gaba Vill.; 28°40.254'N, 97°27.780'E, 2460 m elev.; 24.VII.2013; L. Lin leg.

The specific name is a noun in apposition taken from the type locality.

The new species is similar to T. longling Tong, Zhang & Li, 2019 in the ridges on posterior part of the male sternum, the small slit of the male epigastric region and the T-shaped sclerite of the endogyne, but can be distinguished by the elongated male palpal femur (Fig. 12D) vs. globular (Tong et al. 2019: fig. 13A), the cluster of bristle-like structures (cbs) on the median area of the bulb (Figs 12A, J) vs. lacking (Tong et al. 2019: fig. 13A), the long, belt-like structure (bls) of the psembolus (Fig. 12I) vs. many fiber-like lobes (Tong et al. 2019: fig. 13B), and the transversally elongated membranous structure (tms) of the endogyne (Fig. 14H) vs. lacking (Tong et al. 2019: fig. 24J).

Male. Body: yellowish-brown, legs lighter; habitus as in Fig. 11A, C, E; body length 1.64. Carapace (Fig. 11B, F): 0.72 long, 0.58 wide; sides granulate. Eyes (Fig. 11B, F): eyes well developed, nearly equal in size; ALE separated from edge of carapace by 1.4 diameters. Mouthparts (Figs 5K, 11D, H): endites distally branched. Sternum (Fig. 11D): surface smooth; with several rows of ridges in posterior part. Abdomen (Fig. 11A, C, E, G): 0.84 long, 0.49 wide; surface smooth; sperm pore situated at level of anterior spiracles; with small slit anterior of groove connecting posterior spiracles. Palp (Fig. 12A–K): orange; 0.54 long (0.17, 0.10, 0.09, 0.16); femur elongated (width/length = 0.52); bulb triangle, with cluster of bristle-like structure (cbs) on median area; psembolus with long, belt-like structure (bls), a lateral curved branch (lb) and broad median branch (mb).

Figure 11. 

Trilacuna zayu sp. nov., male holotype A, C, E habitus, dorsal, ventral and lateral views B, D, F, H prosoma, dorsal, ventral, lateral and anterior views, arrow in D shows the small ridges G abdomen, ventral view, arrow shows the small slit. Scale bars: 0.4 mm.

Figure 12. 

Trilacuna zayu sp. nov., male left palp A–C (light) and D–K (SEM) A, D prolateral view B, E dorsal view C, F retrolateral view G bulb, prolateral view H, I, K distal part of bulb, dorsal, prolateral and retrolateral views J detail of bulb, prolateral view. Abbreviations: bls = belt-like structure; cbs = cluster of bristle-like structure; lb = lateral branch; mb = median branch. Scale bars: 0.1 mm (A–G); 0.05 mm (H–K).

Figure 13. 

Trilacuna zayu sp. nov., female paratype A, C, E habitus, dorsal, ventral and lateral views B, D, F, H prosoma, dorsal, ventral, lateral and anterior views G abdomen, ventral view. Scale bars: 0.4 mm.

Female. Same as male except as noted. Body: length 1.89; habitus as in Fig. 13A, C, E. Carapace: 0.77 long, 0.63 wide. Abdomen: 1.06 long, 0.67 wide. Epigastric area (Figs 13A, 14G): with recurved, strongly sclerotized arches (sar). Endogyne (Fig. 14H): with narrow, transverse sclerite (tsc) and broad, transversally elongated membranous structure (tms); with anterior slender sclerite (as) and posterior small globular structure (glo); transverse bars (tba) with pair of short lateral apodemes (ap).

Figure 14. 

Trilacuna spp., endogyne A, B Trilacuna mainling sp. nov. C, D Trilacuna metok sp. nov. E, F Trilacuna bangla Grismado & Ramírez, 2014 G, H Trilacuna zayu sp. nov. A, C, E, G ventral view B, D, F, H dorsal view. Abbreviations: ap = apodeme; as = anterior sclerite; glo = globular structure; psp = posterior spiracle; sar = sclerotized, recurved arches; tba = transverse bars; tms = transverse membranous structure; tsc = transverse sclerite. Scale bars: 0.1 mm.

Known only from the type locality (Fig. 1).