The oldest Calosargus Mostovski, 1997 from the Middle Jurassic of China (Diptera: Brachycera: Archisargidae) Author Zhang, Kuiyan Author Yang, Ding Author Shih, Dong Ren Chungkun text Zootaxa 2007 1645 1 17 journal article 10.5281/zenodo.179727 de333d52-b2e2-47cb-b3de-5c313a86ad12 1175-5326 179727 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 . 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. 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.