Archirhagio zhangi Zhang, Yang & Ren

Zhang, Kuiyan, Li, Jinhua, Yang, Ding & Ren, Dong, 2009, A new species of Archirhagio Rohdendorf, 1938 from the Middle Jurassic of Inner Mongolia of China (Diptera: Archisargidae), Zootaxa 1984, pp. 61-65 : 62-64

Archirhagio zhangi Zhang, Yang & Ren , sp. nov.

( Figs. 1–2 )

Diagnosis. Body large and stout. Eyes bare, dichoptic, ommatidia visible clearly, occiput with dense hairs. Hind legs slender. Vein R4 short, about half as long as vein M1; vein Rs slightly shorter than distance between beginning of vein R2+3 and crossvein r-m; relative lengths of vein R5 and distance between crossvein r-m and beginning of vein R4 about 1: 2; crossvein r-m located at middle of cell d; vein CuA1 about twice as long as vein CuA2; mouth of cell r1 narrow, about half as wide as that of cell r2+3.

Etymology. The specific name is dedicated to Mr. Zhang Xinliao, the Director of Henan Geological Museum, for his practical help for this study.

Holotype. 41H II 0078-1, 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, the Middle Jurassic (Aalenian-Bajocian).

Description. Body length 21.0 mm; wing length 17.5 mm, wing width 3.8 mm.

Body large and stout. Head elliptical in dorsal view, slightly narrower than thorax. Eyes bare, dichoptic, ommatidia visible clearly, occiput with dense hairs.

Thorax black. Hind legs: femur slightly longer than tibia, both of them slender. Wing distinctly elongated, hyaline: Vein C ending at wing tip; vein Sc long, far beyond middle of wing. Veins R1 and R2+3 long; vein R4 short, about half as long as vein M1; vein Rs slightly shorter than distance between beginning of vein R2+3 and crossvein r-m; vein R2+3 arising slightly distal of base of cell d; vein R5 ending far beyond apex of wing, relative lengths of vein R5 and distance between crossvein r-m and beginning of vein R4 about 1: 2. Crossvein r-m located at middle of cell d. Vein CuA1 arising from cell bm, about twice as long as vein CuA2; vein CuP well visible. Cell sc wide open, mouth of it about 14 times as wide as that of cell r1, mouth of cell r1 narrow, about half as wide as that of cell r2+3; mouth of cell r4 about twice as wide as that of cell r2+3. Cell d slender, slightly longer than vein M1. Five posterior cells wide open. Mouth of cell m1 slightly narrower than that of cell m2; mouth of cell m2 about twice as wide as that of cell m3. Cell cup narrowly open, its mouth about 1/10 as wide as that of cell cua1. Anal lobe narrow, alula present.

Abdomen robust, cylindrical; 8 segments visible. Segment I evidently short. Each of segments I-VI with a speckle at posterolateral corner, left speckle of segments II-IV absent. Cerci with 2 segments.

Remarks. Archirhagio zhangi sp. nov. is similar to A. obscurus Rohdendorf in the following aspects: vein Rs slightly shorter than distance between beginning of vein R2+3 and crossvein r-m; crossvein r-m located at middle of cell d; cell sc wide open, mouth of cell r1 narrow, about half as wide as that of cell r2+3. However, it can be easily separated from the latter by vein R5 short, relative lengths of vein R5 and distance between crossvein r-m and beginning of vein R4 about 1: 2; cell d slender; vein CuA1 about twice as long as vein CuA2; on abdomen, each of segments I-VI with a speckle at posterolateral corner. In A. obscurus , vein R5 long, relative lengths of vein R5 and distance between crossvein r-m and beginning of vein R4 about 1: 1.3; cell d wider than that in zhangi ; vein CuA2 long, much longer than 1/2 of vein CuA1; abdomen without any speckle. A. zhangi sp. nov. is also similar to A. striatus Zhang et Zhang more or less. But, we can distinguish it from A. striatus by vein Rs slightly shorter than distance between beginning of vein R2+3 and crossvein r-m; vein R5 short, relative lengths of vein R5 and distance between crossvein r-m and beginning of vein R4 about 1: 2; cell d slender, crossvein r-m located at its middle; vein CuA1 about twice as long as vein CuA2; cell sc wide open, its mouth about 14 times as wide as that of cell r1, mouth of cell r1 narrow, about half as wide as that of cell r2+3; abdominal segments I-VI each with a speckle at posterolateral corner, without any stripe. In A. striatus , vein Rs slightly longer than distance between beginning of vein R2+3 and crossvein r-m; vein R5 long, relative lengths of vein R5 and distance between crossvein r-m and beginning of vein R4 about 1: 1.3; cell d wider than that in A.zhangi , crossvein r-m located at its basal 2/5; vein CuA2 long, much longer than 1/2 of vein CuA1; cell sc narrower than that in A.zhangi , its mouth about 3 times as wide as that of cell r1, mouth of cell r1 wide open, about as wide as that of cell r2+3; abdomen with a stripe, without any speckles. Besides, the size of the new species is distinctly larger than the others. In wing length, Archirhagio zhangi sp. nov. is 17.5 mm; A. obscurus is 13 mm; A. striatus is 9.8 mm.

Figures

FIGURE 1. Archirhagio zhangi sp. nov. Holotype, photographs. (A) Body with wings in dorsal view; (B) apex of abdomen.

FIGURE 2. Archirhagio zhangi sp. nov. Holotype, camera lucida drawing, based on the original photograph, in dorsal view.