Trilacuna xiaoheishan Tong, Yang & Zhang, 2023

Ma, Jimeng, Bian, Dongju, Tong, Yanfeng, Yang, Zizhong & Zhang, Zhisheng, 2023, Three new species of the genus Trilacuna Tong & Li, 2007 (Araneae, Oonopidae) from Yunnan Province, China, ZooKeys 1174, pp. 289-300 : 289

Trilacuna xiaoheishan Tong, Yang & Zhang sp. nov.

Figs 5 , 6 , 7 , 8

Type material.

Holotype ♂ (SYNU-653): China, Yunnan Province, Baoshan City, Longling County, Xiaoheishan Natural Reserve, Z. Li & L. Wang leg., 17/2/2011; Paratypes 1 ♂ (SYNU-654),1 ♀ (SYNU-655), 2 ♀ (SYNU-656-657), same data as holotype.

Diagnosis.

Males of the new species are similar to those of T. werni Eichenberger, 2011 in the shape of the male palp, but they can be distinguished by the branch of psembolus with row of combs (Fig. 6D, J ) vs a groove with row of lobes ( Eichenberger and Kranz-Baltensperger 2011: fig. 12A, B, E, I), and the unfused abdominal dorsal and ventral scuta (Fig. 5C ) vs dorsal scutum fused to the epigastric scutum ( Eichenberger and Kranz-Baltensperger 2011: fig. 11C). Females can be distinguished from the other Trilacuna species by the curved posterior margin of epigastric scutum (Fig. 7F, G ) vs roundly bent.

Description.

Male (holotype). Body: reddish-brown, chelicerae and sternum lighter, legs yellow; habitus as in Fig. 5A-C ; body length 2.37. Carapace: 1.08 long, 0.89 wide; sides smooth, lateral margin rebordered (Fig. 5D ). Eyes: ALE largest, PME smallest; ALE separated from edge of carapace by 0.93 diameters (Fig. 5D, F ). Mouthparts: chelicerae straight, proximal region with one hair with elevated hair base; labium rectangular, anterior margin deeply incised; endites slender, distally not branched (Fig. 5E, G, H ). Sternum: surface strongly rugose (Fig. 5E ). Abdomen: 1.36 long, 0.92 wide; booklung covers ovoid, surface smooth; apodemes present; sperm pore situated at level of anterior spiracles; posterior spiracles connected by groove (Fig. 5A-C ). Palp: orange; 0.79 long (0.24, 0.15, 0.17, 0.23); femur greatly elongated (width/length = 0.61); bulb triangle, tapering anteriorly; psembolus with a long distally widened flat branch (wfb), with a row of combs (brc) at basal half of the branch and numerous “hairs” on distal half of the branch; with a retrolateraly long curved branch (lcb), a short dorsal branch (sdb) and a thin median branch (tmb) (Fig. 6 ).

Female (paratype, SYNU-655). Body: habitus as in Fig. 7A-C ; slightly larger than male; body length 2.57. Carapace: 1.09 long, 0.91 wide. Mouthparts: endites unmodified. Abdomen: 1.60 long, 1.13 wide. Epigastric area: middle part of posterior margin of epigastric scutum curved, with sclerotized recurved arches (sar) between posterior spiracles (psp) (Fig. 7F, G ). Endogyne: with narrow, transversally elongated sclerite (tsc); anterior T-shaped sclerite (as) and posterior small globular structure (glo) (Fig. 7G, H ).

Etymology.

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

Distribution.

Known only from the type locality, Yunnan Province, China (Fig. 8 ).

Figures

Figure 5. Trilacuna xiaoheishan sp. nov., male holotype A-C habitus in dorsal, ventral, and lateral views D-F prosoma in dorsal, ventral, and anterior views G labium and endites in ventral view H chelicerae, anterior view. Abbreviations: ehb = elevated hair base; ldi = labium deep incision. Scale bars: 0.4 mm (A-F); 0.2 mm (G, H).

Figure 6. Trilacuna xiaoheishan sp. nov., left male palp A-F (light) and G-L (SEM) A, G prolateral view B, H dorsal view C, I retrolateral view D, J distal part of bulb, prolateral view E, K distal part of bulb, dorsal view F, L distal part of bulb, retrolateral view. Abbreviations: brc = branch with row of combs; sdb = short dorsal branch; lcb = lateral curved branch; tmb = thin median branch; wfb = distally widened flat branch. Scale bars: 0.1 mm (A-C, G-I); 0.05 mm (D-F, J-L).

Figure 7. Trilacuna xiaoheishan sp. nov., female paratype A-C habitus in dorsal, ventral, and lateral views D, E prosoma in dorsal and ventral views F abdomen in ventral view G, H copulatory organ in ventral and dorsal views, arrow shows the curved posterior margin. Abbreviations: ap = apodemes; as = anterior sclerite; glo = globular structure; psp = posterior spiracle; sar = sclerotized, recurved arches; tsc = transverse sclerite. Scale bars: 0.4 mm (A-F); 0.2 mm (G, H).

Figure 8. Distribution records of three new species from Yunnan, China. 1. Trilacuna cangshan sp. nov.; 2. Trilacuna wumanshan sp. nov.; 3. Trilacuna xiaoheishan sp. nov.