Tetroxyrhina dentata, Shi, Li, Gaimari, Stephen D. & Yang, Ding, 2017

Shi, Li, Gaimari, Stephen D. & Yang, Ding, 2017, Five new species of the genus Tetroxyrhina Hendel from China (Diptera, Lauxaniidae), Zootaxa 4247 (3), pp. 246-280 : 251

Tetroxyrhina dentata sp. nov.

( Figs 5–8 , 42–45 )

Diagnosis. Frons with a broad brown stripe extending to ocellar triangle. Arista brown, pubescent. Fore tarsomeres 3–5 brown, mid and hind tarsomeres 4–5 pale brown. Wing intensely brown along costal margin; a weak brown spot on each of crossveins r-m and dm-cu. Abdomen yellow, tergites 1–6 each with a pair of blackish brown triangular lateral spots; female tergite 7 entirely brown on posterior margin.

Description. MALE. Body length 3.9–4.1 mm, wing length 3.6–3.8 mm. FEMALE. Body length 4.1 mm, wing length 3.6 mm.

Head ( Figs. 42–43 ) yellow. Frons with a broad brown stripe extending to ocellar triangle, and black short setulae on anterior 2/3, nearly 1.5 times longer than wide and parallel-sided; ocellar triangle blackish gray; anterior fronto-orbital setae reclinate, slightly shorter than the posterior. Facial keel distinct on upper part between bases of antennae; gena about 1/2 height of eye, with a wide brown stripe. Antenna brownish yellow (antennae broken off in female), 1st flagellomere rounded apically, nearly 1.6 times longer than high; arista brown, pubescent. Orbitoantennal spot distinct, present as a black rectangular spot between eye and antenna. Proboscis mostly yellow except pale brown at tip, with yellow and blackish setulae; palpus yellow with black setulae.

Thorax ( Figs. 42–43 ) yellow and brown with sparse grayish white pruinosity. Mesonotum pale brown with narrow yellow dorsocentral vittae and a narrow yellow median vitta, area adjacent to scutellum yellow; scutellum pale yellow with pair of narrow pale brown stripes; 0+3 dorsocentral setae, acrostichal setulae in 4 rows; prescutellar acrostichal seta shorter than 1st postsutural dorsocentral seta; anepisternum pale brown except slightly yellow on upper margin, and katepisternum blackish brown with sparse grayish white pruinosity; 1 anepisternal seta, 1 katepisternal seta. Legs mostly yellow, except fore tarsomeres 3–5 brown, mid and hind tarsomeres 4–5 pale brown. Fore femur with 5 posteroventral setae, 8 posterodorsal setae; fore tibia with 1 preapical anterodorsal seta and 1 weak apicoventral seta. Mid femur with 1 weak apicoposterior seta; mid tibia with 1 strong preapical anterodorsal seta, 1 strong apicoventral seta. Hind femur with 1 weak preapical anterodorsal seta; hind tibia with 1 preapical anterodorsal seta and 1 short apicoventral seta. Wing ( Fig. 44 ) slightly darkened hyaline, with darker brown along costal margin; a weak brown spot on each of crossveins r-m and dm-cu; subcostal cell brown; costa with 2nd (between R1 and R2+3), 3rd (between R2+3 and R4+5) and 4th (between R4+5 and M1) sections in proportion of 6.3: 1.3:1; crossvein r-m beyond middle of discal cell; ultimate and penultimate sections of M 1 in proportion of 1:1.2; ultimate section of CuA1 about 1/5 of penultimate. Halter yellow except knob black.

Abdomen ( Fig. 42 ) yellow in dorsal view, tergites 1–6 each with a pair of blackish brown triangular lateral spots; female tergite 7 entirely brown on posterior margin; male sternite 6 membranous with an associated pair of triangular sclerites. Male genitalia ( Figs 5–8 , 45 ): epandrium triangular, with a pair of black conical dorsoapical processes in lateral view and a tiny ventral incision in posterior view; surstylus with short setulae; hypandrium broad, with a tiny concavity on two lateral processes; phallus consisting of a pair of claviform sclerites, with apical teeth in lateral view.

Type material. Holotype male ( CAUC), CHINA, Yunnan Province: Mengla, Menglun zhiwuyuan, 570 m, 22. IV. 2007, Hui Dong . Paratypes: 1 male ( CAUC), CHINA, Yunnan Province: Menglun, No. 55 area, 920 m, 31. V. 2007, Wenliang Li ; 1 female ( CAUC), CHINA, Yunnan Province: Mengla, Menglun zhiwuyuan, 570 m, 22. IV. 2007, Hui Dong.

Distribution. China (Yunnan).

Remarks. The new species is very similar to Tetroxyrhina forficula Shatalkin from Japan in having a yellow palpus, and the wing being intensely brown along the costal margin, but it can be separated from the latter by fore tarsomeres 3–5 being brown; the wing having a weak brown spot on each of crossveins r-m and dm-cu; the abdomen being yellow, tergites 1–6 each having a pair of blackish brown triangular lateral spots; and female tergite 7 being entirely brown on posterior margin. In Tetr. forficula , only fore tarsomeres 2–5 are brown; the wing has a distinct brown cloud on each of crossveins r-m and dm-cu; and the abdominal tergites are blackish brown with blurry longitudinal stripes in dorsal view ( Shatalkin, 1997).

Etymology. Latin, dentata , meaning toothed, referring to the phallus with apical teeth in lateral view; a feminine adjective.

Figures

FIGURES 5 – 8. Tetroxyrhina dentata sp. nov., male genitalia. 5 – 6. Epandrial complex: 5. lateral view; 6. posterior view. 7 – 8. Phallus complex: 7. ventral view; 8. lateral view. Scale 0.1 mm.

FIGURES 42 – 45. Tetroxyrhina dentata sp. nov., holotype male. 42. Habitus, lateral view. 43. Head and thorax, dorsolateral view. 44. Wing. 45. Abdominal apex, oblique view.