Scaptesyle sinotricolor Huang & Volynkin sp. nov.

Figs 1–3, 9, 10, 13

Type material. Holotype (Figs 1, 9): male, handwritten label “ 19-VI-2023 | ĦƋDZṉƃū白村 [Xizang, Motuo, Yigong, Bai Village] | 1500–1800 m | leg. NJẍä [Rong-jia Chen] 李+& [Yu-fei Li] ” / handwritten label “[Slide No.] ScXZ01 ” (SCAU).

Paratypes: 2 males, 1 female, same data as holotype, slide Nos.: ScXZ02 (male) and ScXZ03 (female).

Diagnosis. Superficially, S. sinotricolor sp. nov. can be easily distinguished from S. tricolor (Figs 4–6, 11, 14, 15) and S. plumosus (Figs 7, 8, 12, 16) by the smaller male (length of forewing 11.8 mm against 13.5–14.0 mm in S. tricolor and 14.0 mm in S. plumosus) with densely ciliate antennae (filiform in S. tricolor and sparsely ciliate in S. plumosus) and the longer marginal band on hindwing (marginal band terminates at vein Cu 2 in both S. tricolor and S. plumosus), the broader black band on the forewing in both sexes, and the smaller brownish red patch on the forewing in female. The male genital capsule of S. sinotricolor sp. nov. differs clearly from the congeners in its more robust and longer distal section of the uncus, the narrower and smaller setae on the tegumenal arms, the smaller protrusion of the inner crest of editum, the smaller and weaker distal saccular plate, and the apically rounded distal extension of the editum-costa complex (it is apically pointed in both S. tricolor and S. plumosus). The phallus of S. sinotricolor sp. nov. is considerably narrower and smaller (in proportion to the genital capsule) than in the congeners. In the vesica structure, the new species differs from the similar species in the shorter and narrower vesica, the longer spinules on the apical diverticulum, the lack of medial diverticulum and the lack of spinules field on the distal ventral diverticulum. In the female genitalia, the new species is distinguished from the two congeners by its much shorter ductus bursae, the markedly shorter and conical appendix bursae (it is helicoid in both S. tricolor and S. plumosus), and the presence of a dense cluster of spinules occupying the anterior section of the ductus bursae and the posterior section of the corpus bursae. Unlike the new species, the corpus bursae of S. tricolor and S. plumosus bears a ribbon-like signum posteriorly, which is heavily sclerotised and covered with short but robust denticles in the former species while in S. plumosus, it is weakly sclerotised and scattered with smaller denticles. The new species is also somewhat similar to S. luzonica Swinhoe, 1916 and S. aphrodite Kishida, 2023 from the Philippines, but it can be distinguished from both congeners by the smaller brownish red patch on forewing in the female.

Description. Male (Figs 1, 2). Length of forewing 11.8 mm. Head black. Antenna black, densely ciliate. Thorax black with yellow patagia. Forewing ground colour yellow with black and brownish red patterns. Base of wing black. Subbasal to medial area yellow. Postdiscal band black, slightly narrowed medially. Outer one third of wing occupied by large trapezoid brownish red patch. Cilia black. Hindwing ground colour yellow with black marginal band stretching along outer margin and gradually narrowing from apex to anal angle. Cilia short and black on outer margin and piliform and yellow on anal margin. Abdomen black, its genital segments covered by ochreous piliform scales. Male genitalia (Figs 9, 10). Distal section of uncus elongate and slender, evenly tapered towards its tip; basal section of uncus semi-oval, laterally with two clusters of long and thick setae. Arms of tegumen broad and fused in their dorsal 3/4, with two clusters of long and thick setae situated near junction with vinculum. Scaphium thin and weakly sclerotised. Pleurite ear-like, ventrally fused with dorsal end of vinculum. Vinculum somewhat longer than tegumen and with U-shaped saccus. Valva narrowly lobular, more than two-thirds of its length falling on long linguiform, weakly membranous valvula. Proximal section of costa trapezoidal while distal section separated from valvula and extended into free and strongly elongate, smoothly downcurved and apically rounded, heavily sclerotised distal process stretching along about one third of valva length. Editum fused with ventral margin of proximal section of costa and distally protruding into base of distal costal process, while its proximal section with crest directed inwards and bearing a short tooth-like protrusion. Tendon well-sclerotised, rod-like, separated from its counterpart by diaphragmal membrane. Sacculus proximally broad (ca. 2/3 of valva width); dorsal section of sacculus protruding inwards as large crest and distally extended into elongate and apically rounded, weakly sclerotised plate deeply protruding into valvula. Juxta ventrally articulated with bases of sacculi while its main part separated from diaphragmal membrane as moveable, trapezoidal plate dorsally (apically) bearing dense cluster of robust, spiniform setae. Anellus and manica evenly scobinate. Phallus cylindrical, downcurved medially with short and semioval coecum. Main chamber of vesica sack-like; 1 st proximal diverticulum nearly rectangular, membranous; 2 nd proximal diverticulum sack-like and membranous; medial diverticulum absent; distal diverticulum utricular and distally tapered, membranous; apical diverticulum globular, bearing field of spinules. Vesica ejaculatorius with long and stick-shaped elasma. Female (Fig. 3). Length of forewing 14.0 mm. Body as in male. Antenna black, sparsely ciliate. Forewing as in male but with smaller distal brownish red patch. Hindwing as in male. Female genitalia (Fig. 13). Papilla analis trapezoidal with rounded corners, weakly setose posteriorly and bearing larger setae anteriorly. Apophyses equally thin, apophysis anterioris about one fifth length of apophysis posterioris. Postvaginal plate semiglobular, weakly sclerotised and rugose. Ductus bursae membranous, its anterior section densely covered by spinules. Corpus bursae oval and membranous with posterior section densely covered by spinules (continuation of spinulose cluster of ductus bursae), and medial section sparsely covered by graniculi. Appendix bursae shortly conical and apically rounded, situated postero-laterally on right side.

Distribution. The new species is currently only known the type locality in SE Xizang, China (Fig. 17).

Etymology. The specific epithet is an aggregate of the Latin prefix ‘sino’ meaning ‘Chinese’ and the speciesgroup name tricolor, and refers to the superficial similarity of the new species to S. tricolor and its distribution. The name is an adjective in apposition to the generic name.