Calosargus (Calosargus) daohugouensis Zhang, Yang & Ren

Zhang, Kuiyan, Yang, Ding & Shih, Dong Ren Chungkun, 2007, The oldest Calosargus Mostovski, 1997 from the Middle Jurassic of China (Diptera: Brachycera: Archisargidae), Zootaxa 1645, pp. 1-17 : 9-10

Calosargus (Calosargus) daohugouensis Zhang, Yang & Ren , sp. nov.

( Figs. 11–12 )

Diagnosis. Vei n R s 1 short, nearly as long as vein Rs2; vein R2+3 arising slightly proximal of base of cell d; vein R2+3 ending at vein R1 far before wing margin; crossvein r-m located at basal 1/3 of cell d; mouth of cell r1 narrow, about 1/4 as wide as that of cell r4; mouth of cell m1 narrower than that of cell m2.

Etymology. The specific name refers to the type locality: Daohugou village, Inner Mongolia, China.

Holotype. CNU-DB-NN2007008, an almost complete adult of unknown sex with wing in lateral view.

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

Description. Body length 8.0 mm; wing length 7.8 mm, wing width 2.5 mm.

Head round in lateral view, slightly narrower than thorax. Eyes large, bare; ommatidia visible clearly.

Thorax black. Middle and hind femora long, slightly swollen; hind tibia slender. Wing elongate, hyaline. Vein C ending at wing tip; veins C and R1 markedly thick; vein Sc long, extending far beyond middle of wing. Ve in R 1 long and robust; vein Rs1 short, nearly as long as vein Rs2; vein R2+3 arising slightly proximal of base of cell d; vein R2+3 ending at vein R1 far before wing margin; vein R4 short, convergent to vein R1; vein R5 ending far beyond apex of wing, relative lengths of vein R5 and vein Rs3 about 3: 5. Crossvein r-m located at basal 1/3 of cell d. Vein M3 absent, vein CuA1 arising from cell d. Cell sc wide open, mouth of cell sc about 3 times as wide as that of cell r4, mouth of cell r1 narrow, about 1/4 as wide as that of cell r4. Cell d wide, mouth of cell m1 narrower than that of cell m2.

Abdomen slender, cylindrical. Three segments visible. Segment I evidently short.

Remarks. C. (C.) daohugouensis sp. nov. could be related to C. (C.) antiquus sp. nov. in the following aspects: vein R2+3 ending at vein R1 far before wing margin; veins R4 and R5 short; base of cell d sharp. However, we can easily separate it from antiquus by vein Rs1 short, nearly as long as vein Rs2; vein R2+3 arising slightly proximal of base of cell d; crossvein r-m located at basal 1/3 of cell d; veins M distinctly long; mouth of cell r1 about 1/4 as wide as that of cell r4; mouth of cell m1 narrower than that of cell m2. In antiquus , vein Rs1 is long, about twice as long as vein Rs2; vein R2+3 is arising slightly distal of the base of cell d; crossvein rm is nearly located at middle of cell d; the branches of vein M are distinctly short; the mouth of cell r1 is about 1/2 as wide as that of cell r4; the mouth of cell m1 is nearly as wide as that of cell m2.

Figures

FIGURE 11. Calosargus (Calosargus) daohugouensis sp. nov. Body with wing photograph in lateral view.

FIGURE 12. Calosargus (Calosargus) daohugouensis sp. nov. Camera lucida drawing, based on the original photograph, in lateral view.