Strenorhagio asymmetricus, Zhang & Yang & Ren & Shih, 2010, Zhang & Yang & Ren & Shih, 2010

Zhang, Kuiyan, Yang, Ding, Ren, Dong & Shih, Chungkun, 2010, An evolutional special case in the lower Orthorrhapha: some attractive fossil flies from the Middle Jurassic of China (Insecta: Diptera: Brachycera), Zoological Journal of the Linnean Society 158 (3), pp. 563-572 : 568-569

STRENORHAGIO ASYMMETRICUS ZHANG, YANG & REN GEN. ET SP. NOV. ( FIGS 5 , 6 )

Etymology: The specific name refers to the Greek ‘ asymmetricus ’ (asymmetric), because of the asymmetric position of crossvein r–m in two wings.

Diagnosis: Hind femur swollen at apical part; each tibia with a spur at apex. Crossvein r–m slightly proximal to beginning of vein R 2+ 3 in left wing, and nearly coalesced with vein R 2+3 at vein Rs (vein Rs 2 nearly disappearing) in right wing; vein CuA 1 arising from cell bm, crossvein m–cu long; basal trunk of veins M 1 and M 2 shorter than crossvein m–m; mouths of cells sc and r 1 wide, relative widths about 4: 3. Segments I–VI with black stripe at each end.

Holotype: CNU-DIB-NN2007020, an almost complete adult body with wings in dorsal view.

Paratype: CNU-DIB-NN2007021, an almost complete adult body with a wing in lateral view.

Type locality and horizon: Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China; Jiulongshan Formation, the Middle Jurassic (Aalenian–Bajocian).

Description: Body length, 13.5 mm; wing length, 8.5 mm; wing width, 3.1 mm.

Body stout. Head round, slightly narrower than thorax. Eyes large, bare; ommatidia clearly visible, with upper area composed of larger facets.

Legs pubescent. Hind femur swollen at apical part; each tibia with a spur at apex; first tarsomere distinctly much longer and wider than following tarsomeres.

Wing hyaline; veins thick and strong. Vein Sc ending slightly beyond middle of wing. Veins R 1 and Rs 1 long; vein R 2+3 distinctly and strongly bent upwards at base; vein R 5 ending slightly beyond wing apex. Crossvein r–m at basal third of cell d; proximal to beginning of vein R 2+ 3 in left wing, nearly coalesced with vein R 2+3 at vein Rs (with vein Rs 2 nearly disappearing) in right wing; vein Rs 1 shorter than vein Rs 3. All branches of vein M long, veins M 1 and M 2 bifurcating distal to crossvein m–m, basal trunk of veins M 1 and M 2 shorter than crossvein m–m. Vein CuA 1 arising from cell bm, crossvein m–cu long; vein CuP present. Mouths of cells sc and r 1 wide, relative widths 4: 3; mouths of cells r 2+3 and r 4 distinctly narrow. Cell bm about as wide as cell br; cell d slender, far from wing margin. Five posterior cells present, and wide open; mouths of cell m 1 slightly narrower than that of cell m 2; mouth of cell m 3 distinctly narrower than that of cell m 1, about half as wide as that of cell cua 1. Cell cup distinctly open.

Abdomen cylindrical, robust, and pubescent. Nine segments visible; segments I–VI with black stripe at each end.

Remarks: Because the position of crossvein r–m is asymmetric in the two wings, the crossvein m–cu is longer, the cell r 1 is narrower, and segments I–VI have black stripe at each end, we can easily separate S. asymmetricus sp. nov. from S. grimaldi sp. nov.

Figures

Figure 5. Strenorhagio asymmetricus sp. nov. Holotype, body with wings in dorsal view. A, photograph. B, camera lucida drawing.

Figure 6. Strenorhagio asymmetricus sp. nov. Paratype, photograph of body with a wing in lateral view.