Dicranomyia (Erostrata) jejuensis sp. nov.

Figs 1, 2

Type material.

Holotype: Korea • ♂; Jeju-do, Seogwipo-si, Namwon-eup, Sillye-ri, Iseungi-oreum Volcanic Cone; 33°20.24'N, 126°37.25'E; alt. 450 m; 4 Aug.-8 Sep. 2021; Y. J. Bae leg.; Malaise trap; GenBank: OM102981; CF21-0150H; NIBR.

Paratypes: Korea • 1 ♀; same data as holotype, 14 Jul.-4 Aug. 2021; GenBank: OM102983; CF21-0151; KUEM • 1 ♂; same data as holotype; GenBank: OM102982; CF21-0150P; KUEM.

Diagnosis.

Palpus is 3-segmented. Male seventh sternite has shallow V-shaped notch. Outer face of gonostylus has single seta arising from tubercle. Distal lobe of paramere has a hooked tip with a subapical process.

Description.

Male (holotype). Body length 4.3 mm, wing length 4.6 mm, antenna length 0.9 mm. General body coloration pale yellow to yellowish brown (Fig. 1A).

Head (Fig. 1B). Dark brown dorsally, pale ventrally. Antennae 14-segmented; scape pale yellow; pedicel yellowish brown; flagellum brown. Rostrum pale, rudimentary. Palpus 3-segmented; basal 2/3 of first palpomere pale; remainder of palpus brown.

Thorax. Prescutum and presutural scutum yellow. Postsutural scutum, scutellum and mediotergite yellowish brown. Pleuron uniformly dull yellow, without lateral stripes. Wing (Fig. 1C) tinged with pale brown; veins brown; Sc ending before middle of Rs; sc-r at tip of Sc; Rs arched at base; R1 and R2 nearly transverse, at the same level; R3 and R4+5 parallel to each other; discal medial cell closed; m-cu before fork of M; CuP ending beyond tip of Sc. Halter pale brown. Legs with coxae and trochanters pale; base of femora pale, remainder of femora brown; tibiae and tarsi brown. Femur II 3.3 mm; femur III 3.8 mm; tibia II 3.5 mm; tibia III 4.0 mm; tarsus II 3.2 mm; tarsus III 2.8 mm. Claw without additional tooth.

Abdomen. Tergites yellowish brown, sternites 1-4 yellow, remaining yellowish brown. Seventh sternite with shallow V-shaped notch with darkened margin (Fig. 1D).

Male terminalia (Fig. 1E-G). Yellow. Ninth tergite with posterior margin rounded (Fig. 1E), medially with distinct emargination, distal part covered with setae. Gonocoxite elongated, approximately 3 × as long as width at base, with elongated, setose ventromesal lobe. Gonostylus yellowish brown at base, turning dark distally; distal 1/2 of gonostylus gradually tapered toward apex, with short black spine at tip; dorsal margin near the base with small tubercle bearing pale, stout seta. Paramere (Fig. 1F, G) with basal 1/2 pale and apical 1/2 yellowish, distal lobe darkened apically with hooked tip and subapical projection. Aedeagus (Fig. 1F) as long as gonocoxite, bifid, curved outwards at tip.

Female. Body length 4.5 mm, wing length 4.8 mm, antenna length 0.9 mm (N = 1). General body coloration brighter than male. Femur I 2.8 mm; II 3.2 mm; III 3.4 mm; tibia I 3.2 mm; I: 3.1 mm; III 3.4 mm; tarsus I 3.0 mm; II 2.6 mm; III 2.4 mm.

Female terminalia (Fig. 1H-I). Yellow. Cercus curved upwardly (Fig. 1H), wider at base, narrowing towards acute tip. Genital fork long, ca 1.5 × as long as width, extending to base of cercus. Hypovalva wedge-shaped, reaching to ca 2/3 of cercus, with distinct black spot at base. Dorsal and ventral margin of hypovalva serrated near tip (Fig. 1I).

Etymology.

Specific name " jejuensis " refers to the type locality, Jejudo Island, Korea.

Distribution.

The species is currently only known from Jejudo Island, Korea.

Habitats.

Adults of this species are found in deciduous forests with moss-covered rocks along intermittent, rocky mountain streams (Fig. 2) and co-occur with D. (E.) submelas .

Period of activity.

Adults were collected from June through early September.

Remarks.

Dicranomyia (E.) jejuensis sp. nov. is morphologically similar to D. (E.) yazuensis based on the male genital structures, but it can be distinguished by the following characters: pleuron entirely dull yellow (vs dark dorsally); palpus 3-segmented (vs 2-segmented); distal 1/2 of gonostylus tapered to tip (vs distal 2/3 strongly narrowed toward tip); posterior margin of male seventh sternite with shallow V-shaped notch (vs long triangular notch); distal part of paramere with hooked tip (vs straight tip).