Trichosia (Trichosia) fumoranea, Sutou & Menzel, 2025

Trichosia (Trichosia) fumoranea sp. nov.

Figs 4 A, B View Figure 4 , 5 A ‒ F View Figure 5

Type material.

Holotype. JAPAN • ♂; Honshu, Kanagawa Pref., Hakone, Tounomine ; 35°14'N, 139°06'E; alt. 250 m; 16 May 2000; M. Sutou leg., sweep-net; NSMT GoogleMaps . Paratypes. JAPAN • 1 ♂ (Fig. 4 A View Figure 4 ); same data as for holotype; SDEI GoogleMaps • 1 ♂; Honshu, Kanagawa Pref., Isehara, Mt. Oyama, Shimosya-Miharudai ; 35°26'N, 139°14'E; alt. 700 m; 12 June 1993; K. Tsukahara leg.; KPMNH GoogleMaps • 1 ♂; Honshu, Kanagawa Pref., Yokohama, Hodogaya, Tokiwadai , evergreen broad-leaved forest dominated by Castanopsis sieboldii (site 1); 35°28'19"N, 139°35'13"E; alt. 60 m; 23 Apr. 2007; M. Sutou leg., sweep-net; SDEI GoogleMaps • 2 ♂♂; same data but coniferous forest dominated by Pinus taeda (site 2); 35°28'15"N, 139°35'34"E; NSMT GoogleMaps • 1 ♀; same data (site 1) but 24 Apr. 2001; SDEI GoogleMaps • 1 ♀; same data (site 1) but 30 May 2012; NSMT GoogleMaps • 2 ♂♂; same data (site 1) but 15 Apr. – 9 May 2002; emergence trap; PCMS GoogleMaps • 2 ♀♀; same data (site 2) but 7 Apr. 1998; reared from larvae and pupae collected at 29 Mar. 1998; PCMS; 2 male pupae were preserved in ethanol; PCMS GoogleMaps .

Description.

Male. Head: Eye bridge 3‒4 facets wide. Prefrons with setae and clypeus bare. Scape and pedicel brown each with about 6‒10 setae; flagellomeres brown except for yellowish base of 1 st flagellomere; 4 th flagellomere about 3.5‒4.0 times as long as wide, neck portion about 1 / 9 of its whole length (Fig. 5 A View Figure 5 ), hairs yellowish brown and slightly longer than width of flagellomere. Palpus yellowish brown, 3 - segmented with length ratio 1.3: 1.0: 1.5, 1 st segment with 2‒5 setae mainly on its outside and without distinct sensory area bearing minute sensilla, 2 nd segment with 4‒7 setae, 3 rd segment slender with 4‒8 setae (Fig. 5 B View Figure 5 ). Thorax: Color predominantly dark brown (Fig. 4 A View Figure 4 ); setae on mesonotum and scutellum consist of longer and shorter ones; posterior pronotum bare. Coxae, femora, and tibiae predominantly yellowish brown, tarsi brown (Fig. 4 A View Figure 4 ); middle tibia, hind tibia, and basitarsi of all legs with differentiated spine-like short setae in ground setosity; fore tibial spur about 1.1‒1.2 times as long as width of tibial apex (Fig. 5 E View Figure 5 ). Wing with brownish anterior veins and light brownish posterior veins (Fig. 4 B View Figure 4 ); wing membrane fumous, with numerous macrotrichia and minute pits in which base of macrotrichia are embedded (Figs 4 B View Figure 4 , 5 F View Figure 5 ); R 5 with both dorsal and ventral macrotrichia almost along its whole length, bM bare, r-m, M 1, M 2, stem of M, CuA 1, and CuA 2 with dorsal macrotrichia; length of R 1 = 0.9‒1.0 R, c = 0.7‒ 0.8w, r-m = 0.9‒1.8 bM (x), stem of CuA very short, almost absent; R 1 ending slightly beyond branching point of M 1 and M 2; wing length 3.4‒3.7 mm. Halter brown, knob and distal 1 / 4‒1 / 3 of stalk with setae. Abdomen: Tergites and sternites dark brown with dark brownish setae, abdominal segments slender (Fig. 4 A View Figure 4 ). Gonocoxite wider than long (Fig. 5 C View Figure 5 ); gonostylus longer than wide, its inside with a wide lobe on which some spines are present (Fig. 5 D View Figure 5 ); upper half of tegmen nearly quadrate with two pocket-like structures (Fig. 5 C View Figure 5 ), upper margin of tegmen fringed with fine teeth; aedeagus nearly Y-shaped (Fig. 5 C View Figure 5 ). Body size: 3.5‒3.8 mm.

Female. Similar to male, but 4 th flagellomere about 3.0 times as long as wide, hairs almost as long as width of flagellomere. Wing length 3.5‒3.8 mm. Body size 3.6‒4.8 mm.

Remarks.

The name of this new species alludes to its blackish body color including fumous wings (Fig. 4 View Figure 4 ). It is so far the only Japanese Trichosia species whose wing surface is mostly covered with numerous macrotrichia (Figs 4 B View Figure 4 , 5 F View Figure 5 ). This character helps in identifying the females of this species. The gonostylus has a wide lobe inside, in which some spines are developed (Fig. 5 D View Figure 5 ). T. fumoranea is easily distinguished from previously known Trichosia species by this character. In 1998, two females of this species were reared from larvae collected from rotten wood. In 2002, two males were collected by emergence traps set on the forest floor. These records suggest that the larvae of this species are xylophagous living in rotten wood and branches on forest floor. Otherwise they may have an intermediate habit between xylophagous and phytosaprophagous.