Loxocera (Loxocera) chikuni, 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) chikuni sp. nov.

Figs 1-4 , 5-8

Type material.

Holotype (♂): China, Hubei, Shennongjia, Guanmenshan, 1560 m, 2019.viii.12, leg. Ding Yang (CAU).

Diagnosis.

Generally blackish brown; face blackish; antennal scape and pedicel subequal in length; apex of antennal first flagellomere not produced beyond base of arista; arista laterally compressed and very high, arising at apex of first flagellomere and 1.8 times as long as the latter; wing with broad, transverse, dark band at level of posterior crossvein; hypandrial lobe small, short, covered with long setae; pregonite stout, lobate, apically blunt with rounded processes; phallus tongue-like, relatively short, with rounded posterior margin.

Description.

Male. Body length 9.0 mm, wing length 7.2 mm, length of antenna 2.5 mm. Generally blackish brown, moderately shining (Fig. 1 ). Frontal vitta black, with anterior part yellowish brown (Fig. 2 ); parafacial, gena and posterior eye margin yellowish brown; proboscis and palpus pale brown. Wing slightly infumated, with broad, transverse, dark band at level of posterior crossvein, band more or less interrupted along center of cells r4+5 and dm (Fig. 1 ); wing veins yellowish brown to brown. Halter white with base slightly darkened. Legs with trochanters, apical half of fore and mid femora, fore and mid tibiae, basal half of hind tibia, and tarsomere I pale brown. Bristles on head and thorax black.

Head (Figs 1 , 2 ) transverse oblong in dorsal view, largely glabrous; length along midline 0.8 times as long as width across eyes, width across eyes 1.9 times as broad as interocular space. Frons slightly 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, with silvery tomentose stripes along lateral margins. Face strongly slanting, with weakly 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 (Figs 3 , 4 ) long and thick, with short dense setulae; scape nearly as long as pedicel, gradually widened towards apex of segment; first flagellomere about 2.1 times as long as pedicel, apex very weakly curving ventrally; arista laterally compressed and very high, arising at apex of first flagellomere, 1.8 times as long as first flagellomere, divided into small aristomere 1 and large aristomeres 2+3. Palpus elongate oval, with short, dense setulae and long, scattered setae.

Thorax (Fig. 1 ) robust, with short, dense, whitish-yellow setulae, except anepisternum (anterior half), anepimeron, katatergite, meron, scutellum and mediotergite (middle portion) glabrous; anatergite with fine tomentum; disc of scutellum with fine wrinkles. Scutum 1.4 times as long as wide. Scutellum subtriangular, slightly swollen, and wider than long. Thoracic chaetotaxy: 1 dorsocentral seta, 1 notopleural seta, 2 posterior supra-alar setae, 1 apical scutellar seta. Wing (Fig. 1 ) 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, fore and mid tibiae straight, hind tibia finely curved.

Abdomen elongate, with short, dense, whitish-yellow and black setae; syntergite 1+2 with several long, hair-like setae laterally.

Male genitalia: Sternite 8 (Figs 5 , 6 ) broad, relatively flattened, with long, dense setae. Cerci (Figs 5 , 6 ) small, simple in shape, with short, dense setae. Hypandrium (Fig. 8 ) well developed; hypandrial arms fused posterodorsally, posteriorly produced into small, short, convex lobes covered with long setae (Figs 5-8 ). Hypandrial bridge present and robust. Pregonite (Figs 5-7 ) stout, lobate, apically blunt, with some rounded processes. Phallus (Figs 5-7 ) tongue-like, relatively short, with rounded posterior margin. Phallotrema (Fig. 7 ) large, flanked by some peculiar, tiny processes. Ejaculatory apodeme (Fig. 6 ) small, hook-like, strongly curved.

Female. Unknown.

Etymology.

The specific epithet is dedicated to the Chinese entomologist Chikun Yang (1925-2006), in honor of his excellent contribution to Chinese insect taxonomy.

Distribution.

China - Hubei: Shennongjia (Fig. 37 ).

Comparative notes.

This new species is similar to L. (L.) fujiana (Wang, 1999) and L. (L.) maculithorax sp. nov. by sharing the laterally compressed and high arista which arises at the apex of the antennal first flagellomere, and the broad, transverse, dark band on the wing. The new species differs from L. (L.) fujiana by the following character states: head blackish brown with anterior part of frontal vitta, parafacial, gena, and posterior eye margin yellowish brown [vs head blackish brown with gena slightly paler in L. (L.) fujiana ]; arista 1.8 times as long as antennal first flagellomere [vs 2 times in L. (L.) fujiana ]; hind tibia pale brown in basal half and blackish brown in apical half [vs uniformly dark brown in L. (L.) fujiana ]; transverse dark band on wing interrupted along cell r2+3 [vs not interrupted in cell r2+3 in L. (L.) fujiana ]. The new species can be separated from L. (L.) maculithorax sp. nov. by the following character states: apex of antennal first flagellomere not produced beyond base of arista [vs produced beyond base of arista in L. (L.) maculithorax sp. nov.]; arista 1.8 times as long as antennal first flagellomere [vs 2.1 times in L. (L.) maculithorax sp. nov.]; mesonotum uniformly blackish brown [vs largely blackish with irregular brownish margin in L. (L.) maculithorax sp. nov.]; abdomen uniformly blackish brown [vs reddish brown with both ends darkened in L. (L.) maculithorax sp. nov.]; male sternite 8 flattened [vs with a small blunt protrusion in L. (L.) maculithorax sp. nov.]; hypandrial lobe of male small and short [vs large and broad in L. (L.) maculithorax sp. nov.].

Figures

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

Figures 1 - 4. Loxocera (Loxocera) chikuni sp. nov., holotype, male 1 habitus, lateral 2 head, dorsal 3 left antenna, dorsal 4 same, lateral. Scale bars: 3 mm (1); 0.5 mm (2); 1 mm (3, 4).

Figures 5 - 8. Loxocera (Loxocera) chikuni sp. nov., male genitalia 5 sternite 8 to genitalia, caudal 6 same, lateral 7 pregonite and phallus, ventral 8 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 bar: 0.25 mm.