Shimamyia vietnamensis Huang & Tachi, 2024, sp. nov.

Shimamyia vietnamensis sp. nov. (Figs. 2E–F, 7) Type material. HOLOTYPE male (BLKU): [V I E T N A M] / Danbri (800 m) 15 km NW. Bao Lok / 29.V– 1.VI.2002 / Ta Huy Thinh. Diagnosis. Gena approximately 0.19 of eye height. Vertex approximately 0.2 of head width in male; antenna with postpedicel approximately 2.5 times as long as pedicel in male; 3 katepisternal setae; male abdominal tergite 4 and 5 with dense recumbent hairs dorsally; male postabdomen with surstylus swollen at middle and rounded apically in lateral view, tapering and strongly curved inward in dorsal view; cerci swollen nearly apex in dorsal view; pregonite tapering and pointed apically; female postabdomen not elongate. Description. Resembling the preceding species, but differing as follows: Body length: 6.36 mm. Male. Head with vertex approximately 0.2 of head width; inner vertical seta about 0.27 of eye height; outer vertical seta 0.58 times as long as inner vertical seta; frontal vitta about 2.2 times as wide as fronto-orbital plate at middle; approximately 8 frontal setae, lowest seta at level of middle of pedicel; 3–4 reclinate orbital setae, anterior seta stronger than posterior one; parafacial about 0.8 times as wide as postpedicel at mid-height; facial ridge with several setae approximately on lower 0.35; gena approximately 0.19 of eye height. Antenna with postpedicel about 2.5 times as long as pedicel, 3 times as long as wide; arista thickened approximately approximately on basal 0.15; palpus near 0.97 of postpedicel; prementum about 3 times as long as wide. Thorax with 2 postpronotal setae; 3 presutural acrostichal setae; 4 postsutural intra-alar setae; 3 katepisternal setae; scutellum with 3 pairs of marginal setae and a pair of discal setae present. Wing tinged with brown anteriorly; tegula and basicosta black; lower calypter brown. Relative lengths of 2nd, 3rd and 4th costal sectors 1.0:2.6:1.2; distance of vein M from crossvein dm-cu to bend about 0.75 times distance between bend and wing margin. Legs with mid tibia with 3 posterodorsal seta; hind tibia with 2 anterodorsal, 2 posterodorsal, 2 ventral setae. Abdominal with very thin whitish pruinosity. Hair very dense, recumbent and fine on dorsum of tergite 4 and 5. Syntergite 1+2 with a pair of lateral discal, a pair of median marginal and 2 pair of lateral marginal seta; tergite 3 with 2 pairs of lateral marginal setae; tergite 4 with a pair of discal setae; tergite 5 with a pair of discal and 12 marginal setae; sternite 5 rounded anteriorly, with some setae on posterior half. Postabdomen. Epandrium nearly trapezoidal and abruptly narrowed at apex and rounded dorsally in lateral view, with some setae; surstylus widened at middle, abruptly narrowed and rounded apically with some setae from apical 2/ 3 in lateral view, curved inward and pointed apically with some setae from apical 2/ 3 in dorsal view; cerci rounded apically with some setae along entire length in lateral view, nearly V-shaped, swollen near apex and pointed apically with some setae along entire length in dorsal view; pregonite pointed apically; postgonite with some setae. Female. Unknown. Etymology. The holotype was collected in Vietnam. Distribution. Vietnam. Remarks. Both this species and S. exigua are distributed in Vietnam. Although the male postabdomens of species are similar, they notably differ in the shape of the cerci and surstyli. In S. exigua, these structures are smoother, whereas in S. vietnamensis, they abruptly narrow at the apex.