First record of the genus Trilacuna Tong & Li, 2007 (Araneae, Oonopidae) from Xizang, China, with descriptions of three new species and one newly recorded species

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).