Tetroxyrhina dashahensis, 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 : 249

Tetroxyrhina dashahensis sp. nov.

( Figs 1–4 , 39–41 )

Diagnosis. Frons with a narrow brown stripe. Arista black, pubescent. Apical tarsomere pale brown. Wing hyaline, with a blurry pale brown spot on R4+5 confluent with round spot on M1; a brown spot on each of crossveins r-m and dm-cu. Abdomen mostly brown in dorsal view, except male tergites 1–6 (female 1–7) each with a pale yellow triangular median spot and tergites 5–6 (female 5–7) yellow on anterior margin.

Description. MALE. Body length 3.7–3.9 mm, wing length 3.9–4.1 mm. FEMALE. Body length 3.7–3.8 mm, wing length 4.3–4.4 mm.

Head ( Figs. 39–40 ) yellow. Frons with a narrow brown stripe extending from anterior margin to ocellar triangle and with black short setulae on anterior 1/2; nearly 1.7 times longer than wide and parallel-sided; ocellar triangle grayish black; anterior fronto-orbital setae reclinate, slightly shorter than the posterior. Face with a pair of brown narrow triangular spots below antennae; gena about 1/2 height of eye, with a wide brown stripe. Antenna yellowish brown, 1st flagellomere rounded apically, nearly 1.4 times longer than high; arista black, pubescent. Orbito-antennal spot distinct, present as a large pale brown triangular spot between eye and antenna. Proboscis and palpus yellow.

Thorax ( Figs. 39–40 ) brown with some sparse grayish white pruinosity. Mesonotum with a pair of narrow yellow dorsocentral vittae and a narrow median vitta, all of which extend through otherwise brown scutellum; 0+3 dorsocentral setae, acrostichal setulae in 4 rows; prescutellar acrostichal seta shorter than 1st postsutural dorsocentral seta; anepisternum and katepisternum brown with sparse grayish white pruinosity, a narrow grayish white stripe through suture between anepisternum and katepisternum; 1 anepisternal seta, 1 katepisternal seta. Legs yellow, except apical tarsomere of each leg 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 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. 41 ) slightly darkened, hyaline, with a blurry pale brown spot on R4+5 confluent with round spot on 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 7.7:1.3:1; crossvein r-m beyond middle of discal cell; ultimate and penultimate sections of M 1 in proportion of 1:1.4; ultimate section of CuA1 about 1/6 of penultimate. Halter yellow except knob blackish brown.

Abdomen ( Fig. 39 ) mostly brown in dorsal view, except male tergites 1–6 (female 1–7) each with a pale yellow triangular median spot and tergites 5–6 (female 5–7) yellow on anterior margin; male sternite 6 membranous. Male genitalia ( Figs 1–4 ): epandrium with a row of anterodorsal setulae and a pair of blackish brown conical dorsoapical processes in posterior view; surstylus rounded with apical setulae in lateral view; hypandrium nearly triangular, widened at middle, narrow and curving downward at two lateral sides, with a lateral tooth; phallus with a pair of lateral processes and broad contortion apically in ventral view.

Type material. Holotype male ( CAUC), CHINA, Guizhou Province: Dasha River, Qianfeng village , 1350– 1500 m, 17. VIII. 2004, Yajun Zhu . Paratypes: 2 males, 2 females ( CAUC), data same as holotype .

Distribution. China (Guizhou).

Remarks. The new species is similar to Tetroxyrhina gressitti Sasakawa from China ( Taiwan) in the wing having a brown spot on each of crossveins r-m and dm-cu, the pattern of abdominal spots, and the epandrium having a long lobate apical process in lateral view, but the new species can be separated from the latter by the epandrium being slender and having an anteroventral process in lateral view; the surstylus being yellow apically; and the hypandrium being nearly triangular in ventral view. In Tetr. gressitti , the epandrium is broad triangular without an anteroventral process; the surstylus is brown apically; and the hypandrium is crescent-shaped in ventral view ( Sasakawa, 2002).

Etymology. The new species is named after the type locality, Dasha River.

Figures

FIGURES 1 – 4. Tetroxyrhina dashahensis sp. nov., male genitalia. 1 – 2. Epandrial complex: 1. lateral view; 2. posterior view. 3 – 4. Phallus complex: 3. ventral view; 4. lateral view. Scale 0.1 mm. Abbreviations: C = cercus; DP = dorsoapical process; Ep = epandrium; EA = ejaculatory apodeme; H = hypandrium; Pa = phallapodeme; Pg = pregonite; Ph = phallus; Pr = protandrium; Ss = surstylus.

FIGURES 39 – 41. Tetroxyrhina dashahensis sp. nov., holotype male. 39. Habitus, lateral view. 40. Head and thorax, dorsal view. 41. Wing.