Tetroxyrhina menglunensis, 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 : 254-256

Tetroxyrhina menglunensis sp. nov.

( Figs 13–16 , 59–61 )

Diagnosis. Frons with a blackish brown median stripe through rows of short setulae extending to ocellar triangle, and two brown stripes through fronto-orbital setae rows extending to inner vertical setae. Antenna yellow, except 1st flagellomere pale brown on apical 1/2, arista brown, pubescent. Tarsomeres 4–5 on all legs pale brown. Wing slightly darker brown along costal margin extending to M1, with a thin white margin between R2+3 and M1; a brown spot on each of crossveins r-m and dm-cu. Abdomen yellow, male tergites 1–5 each with a black posterior margin and tergite 6 with pale brown posterior margin.

Description. MALE. Body length 3.5–3.8 mm, wing length 3.4–3.6 mm.

Head ( Figs. 59–60 ) yellow. Frons with a blackish brown median stripe through rows of short setulae extending to ocellar triangle and two brown stripes through fronto-orbital setae rows extending to inner vertical setae, with sparse short setulae on anterior 1/3; nearly 1.4 times longer than wide and parallel-sided; ocellar triangle grayish black; anterior fronto-orbital setae reclinate, likely shorter than posterior (note, broken off). Facial keel distinct on upper 1/2 between bases of antennae; gena about 2/3 height of eye, with wide brown stripe. Antenna yellow, except 1st flagellomere pale brown on apical 1/2, rounded apically, nearly 1.5 times longer than high; arista brown, pubescent. Orbito-antennal spot distinct, present as a black velvety round spot between eye and base of antenna. Proboscis mostly yellow except pale brown at tip, with yellow and blackish setulae; palpus yellow with black setulae.

Thorax ( Figs. 59–60 ) brown, with sparse grayish white pruinosity. Mesonotum with narrow yellow dorsocentral vittae and narrow median vitta, all of which extend through otherwise brown scutellum; 0+3 dorsocentral setae, acrostichal setulae in 2 rows; prescutellar acrostichal seta shorter than 1st postsutural dorsocentral seta; anepisternum brown and katepisternum darker brown with grayish white pruinosity, a yellow triangular spot at base of katepisternal seta, and yellow stripe through suture between sclerites; 1 anepisternal seta, 1 katepisternal seta. Legs mostly yellow, except tarsomeres 4–5 pale brown. Fore femur with 5 posteroventral setae and 8 posterodorsal setae, fore tibia with 1 preapical anterodorsal seta and 1 short apicoventral seta. Mid tibia with 1 strong preapical anterodorsal seta, 1 strong apicoventral seta. Hind femur with 1 weak preapical anterodorsal seta and a row of weak anteroventral setae; hind tibia with 1 preapical anterodorsal seta and 1 short apicoventral seta. Wing ( Fig. 61 ) slightly darker brown along costal margin extending to M1, a thin hyaline apical margin between R2+3 and M1; a brown spot on each of crossveins r-m and dm-cu; subcostal cell hyaline; 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 9:1.5:1; crossvein rm at middle of discal cell; ultimate and penultimate sections of M 1 in proportion of 1:1.1; ultimate section of CuA1 about 1/7 of penultimate. Halter yellow except knob brown.

Abdomen ( Fig. 59 ) yellow, male tergites 1–5 each with a black posterior margin and tergite 6 with pale brown posterior margin. Male genitalia ( Figs 13–16 ): epandrium with a pair of short conical dorsoapical processes and short dorsal setae; surstylus with sparse setulae; hypandrium broad with a pair of tiny lateral concavities, not curved apically; phallus with a pair of long claviform sclerites, curved backward apically.

FEMALE. Unknown.

Type material. Holotype male ( CAUC), CHINA, Yunnan Province: Menglun , No. 55 area, 920 m, 24. IV. 2007, Hui Dong . Paratype: 1 male ( CAUC), CHINA, Yunnan Province: Menglun , No. 55 area (920 m), 24. IV. 2007, Wenliang Li.

Distribution. China (Yunnan).

Remarks. The new species is very similar to Tetroxyrhina submaculipennis ( Malloch, 1927) from China ( Taiwan) in the frons having a grayish brown median stripe and two lateral stripes, a pale dark spot on the upper part of the face below each antenna, crossveins r-m and dm-cu each with a distinct brown elliptical spot, and the epandrium having a pair of dorsoapical processes in lateral view. But it can be separated from the latter by the legs being mostly yellow except tarsomeres 4–5 being pale brown; the katepisternum being dark brown and having a yellow triangular spot at the base of the katepisternal seta; the male abdomen being yellow, with tergites 1–5 each having a black posterior margin and tergite 6 having a pale brown posterior margin; and the epandrium being broad and the surstylus indistinct with setulae in lateral view. In Tetr. submaculipennis , the legs including the coxae are testaceous yellow; the katepisternum is brown with a pale yellow band along the upper margin; male abdominal tergites 1–4 are almost entirely dark brown except for testaceous yellow lateral margins, and tergites 5–6 are testaceous yellow, each with a pair of brown spots sublaterally (paler and smaller on tergite 6); and the epandrium is slender and the surstylus is longer and incurved in lateral view.

Etymology. The new species is named after the type locality Menglun.

Figures

FIGURES 13 – 16. Tetroxyrhina menglunensis sp. nov., male genitalia. 13 – 14. Epandrial complex: 13. lateral view; 14. posterior view. 15 – 16. Phallus complex: 15. ventral view; 16. lateral view. Scale 0.1 mm.

FIGURES 59 – 61. Tetroxyrhina menglunensis sp. nov., holotype male. 59. Habitus, lateral view. 60. Head and thorax, dorsal view. 61. Wing.