Trichosia (Trichosia) stylofornix Sutou & Menzel, 2025, sp. nov.
Creators: name: Sutou, Mitsuaki
name: Menzel, Frank
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Sciaridae
Trichosia
Trichosia stylofornix

description: Trichosia (Trichosia) stylofornix sp. nov.
Fig. 3 A ‒ D
Type material.
Holotype. JAPAN • ♂; Kyushu, Kumamoto Pref., Aso, Aso National Park, coniferous plantation of Cryptomeria japonica; 32°55'N, 131°06'E; alt. 700 m; 12–14 Oct. 1995; M. Jaschhof leg., aspirator and sweep-net; SDEI. Paratypes. JAPAN • 29 ♂♂; same data as for holotype; 23 ♂♂, SDEI; 2 ♂♂, NSMT; 2 ♂♂, PCMS; 2 ♂♂, MZH • 2 ♂♂; Honshu, Tokyo, Miyake Island, Hinoyama-touge; 34°06'N, 139°33'E; 5–7 Apr. 2010; J. Aoki leg., flight interception trap; SDEI.
Description.
Male. Head: Eye bridge 2‒3 facets wide. Prefrons with about 5 setae and clypeus bare or with a seta. Scape brown with about 5 setae anteriorly, pedicel brown with about 10 setae; flagellomeres brown, base of 1 st flagellomere yellow; 4 th flagellomere about 5.0 times as long as wide, neck portion about 1 / 8 of its whole length (Fig. 3 A), hairs yellowish brown and longer than width of flagellomere. Palpus yellowish brown, 3 - segmented with length ratio 1.8: 1.0: 2.1, 1 st segment with 1‒3 (mostly 2) setae on its outside and with indistinct sensory area bearing minute sensilla, 2 nd segment with 6‒7 setae, frequently one of them distinctly longer than the others, 3 rd segment slender with about 10 setae (Fig. 3 B). Thorax: Color predominantly brown; mesonotum with both short and long setae; scutellum with at most 4 long setae and some short setae; posterior pronotum bare. Coxae, femora, and tibiae predominantly yellowish brown, tarsi brown; tibiae and basitarsi, especially hindtibia with differentiated spine-like short setae in ground setosity; fore tibial spur about 1.2 times as long as width of tibial apex. Wing with brownish anterior veins and light brownish posterior veins; wing membrane bare; distal 1 / 5‒1 / 4 of R 5 with both dorsal and ventral macrotrichia, bM, r-m, M 1, M 2, CuA 1, and CuA 2 with dorsal macrotrichia, stem of M bare or with several dorsal macrotrichia; length of R 1 = 0.6‒0.7 R, c = 0.7‒ 0.8w, r-m = 0.5‒1.0 bM, stem of CuA = 0.3‒0.7 bM; R 1 ending slightly before branching point of M 1 and M 2; wing length 1.8‒2.4 mm. Halter yellowish brown, knob and distal 1 / 4‒1 / 3 of stalk with setae. Abdomen: Tergites and sternites brown with brownish setae, membrane between tergites and sternites yellowish brown. Gonocoxite wider than long (Fig. 3 C); gonostylus longer than wide with apical spines, and inside of dorsal surface with arcuate concavity where 3‒5 spines are present, 2 of them arranged parallel (Fig. 3 D); tegmen membranous, wider than long with weakly sclerotized base (Fig. 3 C); aedeagus nearly V-shaped (Fig. 3 C). Body size: 1.9‒2.9 mm.
Female. Unknown.
Remarks.
This new species is distinctive in having long antennal flagellomeres (Fig. 3 A). It also has unique structures of the gonostylus (Fig. 3 D), and is named after the characteristic arcuate concavity of dorsal surface of the gonostylus (‘ fornix ’ means arch in Latin). The distribution of this species is so far restricted to Kumamoto, southwestern Japan, and Miyake Island, 175 km south of Tokyo metropolis.
description: Published as part of Sutou, Mitsuaki & Menzel, Frank, 2025, The genera Mouffetina Frey and Trichosia Winnertz (Diptera, Sciaridae) in Japan with a key for the Japanese species and an updated world checklist, pp. 167-182 in Contributions to Entomology 75 (1) on pages 167-182, DOI: 10.3897/contrib.entomol.75.e145605