Callomyia triangulata, Tkoč, 2012

Tkoč, Michal, 2012, A new species of the flat-footed fly genus Callomyia (Diptera: Platypezidae) from South China, Acta Entomologica Musei Nationalis Pragae 52 (1), pp. 289-296 : 290-294

Callomyia triangulata sp. nov.

( Figs. 1−8 )

Type locality. China, northern Yunnan, mountain valley 12 km west of Zhongdian (Shangri-La) (D. Král, pers. comm.). Note: The geographic coordinates and altitude given in the locality labels of the type specimens were obtained from an out-dated map and are incorrect (D. Král, pers. comm.).

Type material. HOLOTYPE: ♀, ‘ China N Yunnan, Xue / Shan nr. Zhongdian / 4200 m, 24.vi.1996 / 27,49N / 99,34E // collected by / J. Farkač, P. Kabátek / and A. Smetana // HOLOTYPE / Callomyia / triangulata sp. nov. / M. Tkoč det. 2012’ ( NMPC). PARATYPE: ♀, same label data as the holotype, only third label has ‘PARATYPE’ instead of ‘HOLOTYPE’ ( NMPC).

Description. Female. Body length 4.6 mm (holotype), 4.2 mm (paratype). Wing length 5.2 mm (holotype), 4.8 mm (paratype).

Head ( Figs. 1−3 , 6 ) silvery grey dusted. Antenna ( Fig. 3 ) dark brown, scapus with dorsal seta reaching beyond tip of pedicel, pedicel with one strong dorsal seta reaching tip of second flagellomere, second minor dorsal seta reaching one third of first flagellomere. Three small setae on pedicel in lateral position and one small seta in ventral position. First flagellomere short ovate, twice as long as pedicel. Arista slightly less than two thirds of antennal length. One pair of vertical and orbital setae ( Fig. 2 ) (two pairs of alveoli are present, but the corresponding setae are missing in the type material), 5−8 pairs of short erect frontal setae. Ocellar tubercle dull brown, with one pair of long ocellar setae and one pair of small postocellar setae on posterior margin of the tubercle. Postocular setae moderately long, innermost pair thicker, longer and more curved. Parafacial and gena bare, occiput and postgena with black setae. Occiput silvery grey dusted. Palpus yellow with short setae, proboscis pale yellow with pale pubescence.

Thorax ( Figs. 1 , 4 , 7 ) silvery grey dusted with black markings. Median dorsal stripe velvet black, as wide as one third of thorax width, narrowing in posterior direction. Anterior part of black colouration weaker, especially in anterior view. Black median stripe posteriorly connected with black slightly wider stripe on scutellum. Pleural sides of thorax without bristling, silvery grey coloured, only meron and anepimeron somewhat yellow. All thoracic setae black. Uniserial row of 11 acrostichal setae, but inconspicuous on the black marking. Two rows of 10 dorsocentral setae, the 2 posterior ones stronger and longer. Humerus somewhat yellow, with 2 small humeral setae; small 5−6 posthumeral setae on each side of thorax. One large supraalar and one large postalar seta on each side. Notopleural group composed of 6 setae: 1 st− 4 th of medium length, 5 th + 6 th very long. Two presutural and several postsutural alveoli of setae (the corresponding setae missing in the type material). Scutellum with 2 prominent scutellar setae on each side. Halteres large and bright yellow.

Wing ( Figs. 1 , 6 ) slender and elongate, yellow-tinted with brownish veins, wing base pale yellow. Subcostal cell (sc) less transparent and tinted by white-yellow colour. Wing surface uniformly covered with microtichia, only basal cells with microtrichia sparse. First longitudinal vein (R 1) bearing 19 spines. Anterior (r-m) and posterior (dm-cu) crossveins present. Costal cell (c) equal to sc in length. Posterior crossvein (dm-cu) longer than its distance from the wing margin on the fifth longitudinal vein (CuA 1). Anal cell (cup) elongated, more than twice as long as rest of anal vein (A 1 + CuA 2) beyond it.

Legs ( Figs. 1 , 6 ) slender, yellowish brown with tarsi darker. Coxae yellow with several long black setae. Fore femur with longer thin setae on distal part. Fore tibia with 2 short anteroventral spurs. Mid tibia bearing long dorsal seta above middle and two ventral apical spurs − one long, one short. Hind femur slightly narrower than tibia. Distal parts of femur and tibia of hindleg darker. First tarsomere of hindleg not flattened, narrower than tibia, bearing ventral seta in basal fourth of its length ( Fig. 1 ).

Abdomen ( Figs. 5 , 8 ) yellow and grey silver coloured with brown markings. Pleura whitish, visible from lateral view. Setae on abdomen thin and black. Tergite 1 and 2 (T1+2) more setulose than the others. T1 yellow with small brown area dorsomedially. T2 yellow with elongate dorsomedial brown marking more or less connected with the previous, thicker but narrowing posteriorly, ending at three fourths of its length. T3 yellow, marked with big brown triangle-shaped marking ending close to posterior margin and in lateral view marked with brown spot on each side. T4 mostly brown, two thirds of anterior part brown extending in the middle to posterior margin forming a tip. T5 grey silver shiny dusted with small brown dorsal area in two thirds of anterior part. T6 similar in colouration to T5, but brown marking smaller. T7 small, grey silver dusted. Sternites 1−4 (S1−4) whitish to pale yellow, S5−7 darker yellow brownish with grey shining. S5 and S6 with stronger setae than other sternites.

Male. Unknown.

Differential diagnosis. Callomyia triangulata sp. nov. differs from C. coei mainly by its thoracic and abdominal colouration. The thorax of C. triangulata sp. nov. lacks the two black postsutural areas above wing bases and the median black stripe is less pronounced in its anterior part. The scutellar black stripe is thinner. Tergites 1 and 2 (T1−2) are yellow with brown markings, not silvery orange as in C. coei . T3 is yellow with a brown triangular marking, unlike C. coei which has T3 black. T4 is mostly brown with small yellow posterior spots, T5−6 are silver with small medial brown spots in contrast to T4 orange with thin medial stripe, T5 black and T6 silver dusted as in C. coei .

Other characters in which C. triangulata sp. nov. differs from C. coei are also important to recognize it from other Callomyia species : femur of hindleg is wider than tibia (other Callomyia species have usually tibia wider than femur); wing vein R 1 with 19 short spines (other Callomyia species have usually lower number of these spines).

The European, Russian and Far Eastern Callomyia species may be easily recognized from the new species by the abdominal markings, which are composed of bands and dorsally disconnected bands, but never with a triangular marking ( CHANDLER 2001; SHATALKIN 1982, 1985, 1992). Moreover, the new species differs from C. admirabilis Shatalkin, 1980 by the presence of spines on R 1, and from C. dorsimaculata Shatalkin, 1982 by presence of a dorsal seta on the middle tibia. Callomyia krivosheinae Shatalkin, 1982 has T1−T4 orange with no brown markings and its T6 is black.

Callomyia triangulata sp. nov. could be recognized from the North American species by its generally bright grey and yellow colour of the body (American species are mostly dull or black coloured) and different abdominal colouration. The only American species which has triangular marking on the abdomen is C. clara Kessel, 1949 , but it has the triangle on T4 instead of T3 as in C. triangulata sp. nov. Also, the American species of Callomyia have 9−16 spines on R 1, not 19 as in C. triangulata sp. nov.

Etymology. The Latin adjective triangulata (= three angled) refers to the brown triangular shaped marking on the third abdominal tergite of the female, the most conspicuous diagnostic character of the species.

Biology. Unknown. The type specimens were collected in a montane forested habitat, ca. 4000 m a.s.l.

Distribution. China: Yunnan Province.

Figures

Fig. 1. Callomyia triangulata sp. nov., female, habitus in lateral view.

Figs. 2–3. Callomyia triangulata sp. nov., female: 2 – head, anterior view; 3 – antenna, lateral view.

Figs. 4–5. Callomyia triangulata sp. nov., female: 4 – thorax (chaetotaxy partly reconstructed), dorsal view; 5 – abdomen, dorsal view.

Figs. 6–8. Callomyia triangulata sp. nov., female colouration: 6 – habitus, lateral view; 7 – thorax, dorsal view; 8 – abdomen, dorsal view.