Loxocera (Loxocera) obscura, Zhou & Yang, 2023

Zhou, Jiale & Yang, Ding, 2023, A review of the subgenus Loxocera Meigen, 1803 (Diptera, Brachycera, Psilidae) in China, ZooKeys 1186, pp. 71-96 : 71

Loxocera (Loxocera) obscura sp. nov.

Figs 27-30 , 31-34

Type materials.

Holotype (♂): China, Shaanxi, Xi’an, Zhouzhi, Houzhenzi, 2009.ix.29, leg. Maoling Sheng (CAU). Paratypes: same collection data as for holotype (4♂♂, CAU).

Diagnosis.

Generally dark brown; face blackish; antennal scape distinctly longer than pedicel; antennal first flagellomere stick-like, weakly narrowed towards apex of segment; arista whitish yellow, thin, arising before midpoint of antennal first flagellomere and 1.4 times as long as the latter; wing without transverse dark band; hypandrial lobe very large, broad, covered with short, sparse setae on inner surface; pregonite rather long, slender, curved apically with sharp apex; phallus droplet-like, elongate, abruptly narrowed apically.

Description.

Male. Body length 8.9-10.2 mm, wing length 6.6-7.2 mm, length of antenna 2.2-2.5 mm. Generally dark brown, moderately shining (Fig. 27 ). Frontal vitta black except anterior and median parts brown (Fig. 28 ); face blackish brown; gena and postgena slightly paler (Fig. 29 ). Antenna with arista whitish yellow. Proboscis and palpus pale brown. Mesonotum blackish brown (Fig. 30 ). Scutellum brown (Fig. 30 ). Mesopleuron with anepimeron and katatergite slightly paler; portion above and below anterior spiracle yellow (Fig. 29 ). Wing slightly infumated; wing veins yellowish brown to dark brown. Halter white with base slightly darkened. Fore and mid legs dark yellow, with coxae dark brown, base of femora pale yellow, and mid tarsomeres 2-5 slightly darkened. Hind leg brown, with coxa, femur (except apex), and wide median ring on tibia dark brown. Bristles on head and thorax black.

Head (Figs 28 , 29 ) nearly rounded in dorsal view, largely glabrous; length along midline nearly as long as width across eyes, width across eyes 2 times as broad as interocular space. Frons strongly protruding beyond level of anterior eye margin; frontal vitta with shallow depression at middle; frontal orbit with some short, scattered hairs. Ocellar triangle broad, smooth. Face strongly slanting, with moderately elevated median carina. Parafacial narrow, with a tomentose golden patch between anterior eye margin and lunule. Gena swollen; postgena covered with silvery tomentum. Occiput with a large silvery tomentose patch at middle above foramen. Head chaetotaxy: 1 ocellar seta, 1 postvertical seta, 1 inner vertical seta 1 outer vertical seta. Antenna (Fig. 29 ) long, relatively slender, with short, dense setulae; scape distinctly longer than pedicel; first flagellomere about 4.6 times as long as pedicel, stick-like, laterally compressed, weakly narrowed towards apex; arista thin, arising before midpoint of first flagellomere, 1.4 times as long as first flagellomere, divided into small aristomere 1 and large aristomeres 2+3. Palpus elongate oval, with short, dense, white setulae.

Thorax (Figs 27 , 30 ) robust, with short, dense, white setulae, except anepisternum (anterior half), anepimeron, katatergite, meron, scutellum and mediotergite (middle portion) glabrous; anatergite with fine tomentum. Scutum 1.35 times as long as wide. Scutellum (Fig. 30 ) transverse, wider than long, with midportion distinctly swollen. Thoracic chaetotaxy: 1 dorsocentral seta, 1 notopleural seta, 2 posterior supra-alar setae, 1 apical scutellar seta. Wing with last sector of M1 strongly curved; apex of M4 nearly reaching wing margin. Legs with dense, whitish-yellow setulae, except ventral surface of fore and mid femora largely glabrous; femora subfusiform, slightly compressed laterally; tibiae gradually widened towards apex, hind tibia finely curved.

Abdomen elongate, with short, dense, white setae; syntergite 1+2 with several long, hair-like setae laterally.

Male genitalia: Sternite 8 (Figs 31 , 32 ) broad, inflated, with long, dense setae. Cerci (Figs 31 , 32 ) relatively broad, slightly curved, with short, dense setae. Hypandrium (Fig. 34 ) well developed; hypandrial arms posteriorly produced into very large, broad, convex lobes covered with sparse, short setae on inner surface (Figs 31-34 ). Hypandrial bridge present and robust. Pregonite (Figs 31-33 ) rather long, slender, curved apically with sharp apex. Phallus (Figs 31-33 ) droplet-like, elongate, abruptly narrowed apically. Phallotrema (Fig. 33 ) small, without processes. Ejaculatory apodeme (Fig. 32 ) small, V-like, strongly curved.

Female. Unknown.

Etymology.

The specific epithet is derived from Latin obscura (meaning dark, indistinct), referring to the dark-brown body color of the new species.

Distribution.

China - Shaanxi: Xi’an (Fig. 37 ).

Comparative notes.

This new species is most similar to L. (L.) malaisei (Frey, 1955) (from Myanmar and Nepal) in having a relatively long antennal scape (longer than pedicel), a nearly parallel-sided and laterally compressed antennal first flagellomere, similar coloration of legs, and an enlarged and posteriorly inflated male sternite 8. It can be distinguished from the latter by the following character states: antennal scape about 1.5 times as long as pedicel [vs 2 times in L. (L.) malaisei ]; antennal first flagellomere elongate, 4.6 times as long as pedicel [vs shorter, 4 times in L. (L.) malaisei ]; arista slender [vs widened towards apex in L. (L.) malaisei ]; phallus droplet-like with apex abruptly narrowed [vs elongate oval in L. (L.) malaisei ].

Figures

Figure 37. Known distribution of species of the subgenus Loxocera Loxocera in China.

Figures 27 - 30. Loxocera (Loxocera) obscura sp. nov., holotype, male 27 habitus, lateral 28 head, dorsal 29 same, lateral 30 thorax, dorsal. Scale bars: 3 mm (27); 1 mm (28 - 30).

Figures 31 - 34. Loxocera (Loxocera) obscura sp. nov., male genitalia 31 sternite 8 to genitalia, caudal 32 same, lateral 33 pregonite and phallus, ventral 34 hypandrium and associated structures, ventral. Abbreviations: ce = cercus, ea = ejaculatory apodeme, ep = epandrium, ha = hypandrial arm, hb = hypandrial bridge, hl = hypandrial lobe, pg = pregonite, s 8 = sternite 8, ph = phallus, pt = phallotrema. Scale bars: 0.25 mm (31, 32, 34); 0.1 mm (33).