Protobrachyceron sinensis, Zhang, Kuiyan, Yang, Ding & Ren, Dong, 2008

Zhang, Kuiyan, Yang, Ding & Ren, Dong, 2008, The first Middle Jurassic Protobrachyceron Handlirsch fly (Diptera: Brachycera: Protobrachyceridae) from Inner Mongolia (China), Zootaxa 1879, pp. 61-64 : 63-64

Protobrachyceron sinensis sp. nov.

( Figs. 1–2 )

Diagnosis. Body small, head elliptic. Vein Sc slightly longer than cell br (basal radial); veins R1 and R2+3 close to each other at wing margin; vein Rs slightly longer than distance between beginning of vein R2+3 and crossvein r-m; veins M2, M3 much shorter than vein M1; vein CuA1 arising from cell d, vein CuP well visible; mouth of cell r1 narrow; relative widths of mouths of cells m1, m2 and m3 about 2: 2: 1.

Etymology. The specific name refers to the Latin sina ( China).

Holotype. CNU-DB-NN2008001, an almost complete adult body with both wings in dorsal view.

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

Description. Body length 6.2 mm as preserved; wing length 5.8 mm, wing width 1.7 mm.

Head elliptic in dorsal view, width about 1.5 mm. Eyes large, bare, ommatidia clearly visible. Antennae not preserved. Relative widths of head and thorax about 0.7: 1. Thorax black. Legs slender. Wing elongate, hyaline: Vein C continued around wing as an ambient vein; vein Sc ending at midwing, slightly longer than cell br. Veins R1 and R2+3 close to each other at wing margin; vein Rs slightly longer than distance between beginning of vein R2+3 and crossvein r-m; vein R5 ending at apex of wing, slightly shorter than distance between crossvein r-m and beginning of vein R4; both vein R4 and cell d distinctly shorter than vein M 1 in length. Crossvein r-m at basal 1/4 of cell d; veins M2, M3 much shorter than vein M1. Vein CuA1 arising from cell d, vein CuP well visible. Mouth of cell sc slightly wider than that of cell r2+3; mouth of cell r1 narrow, about half as wide as that of cell r2+3. Cell d wide; five posterior cells widely open; relative widths of mouths of cells m1, m2 and m3 about 2: 2: 1. Abdomen brown, cylindrical; 6 segments visible. Segments II-IV distinctly long and broad. Gender unknown.

Remarks. Protobrachyceron sinensis sp. nov. is very similar to P. liasinum Handlirsch, 1920 in the following aspects: Veins R1 and R2+3 close to each other at wing margin; both vein R4 and cell d distinctly shorter than vein M 1 in length; mouth of cell sc distinctly wider than that of cell r1; five posterior cells widely open. However, we can easily separate it from P. liasinum by vein Rs slightly longer than distance between beginning of vein R2+3 and crossvein r-m; distance between crossvein r-m and beginning of vein R4 about 1.3 times as long as vein R4; vein CuA1 arising from cell d; mouth of cell r2+3 about twice as wide as that of cell r1; relative widths of mouths of cells m1, m2 and m3 about 2: 2: 1. In P. liasinum , vein Rs is more than twice as long as distance between beginning of vein R2+3 and crossvein r-m; distance between crossvein r-m and beginning of vein R4 is about twice as long as vein R4; vein CuA1 is arising from the infall of cell d and cell bm; mouth of cell r2+3 is slightly wider than that of cell r1; relative widths of mouths of cells m1, m2 and m3 is about 6: 9: 1.

Figures

FIGURE 1. Protobrachyceron sinensis sp. nov. Body with wings, photograph in dorsal view.

FIGURE 2. Protobrachyceron sinensis sp. nov. camera lucida drawing, based on the original photograph, in dorsal view.