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 ) antiquus Zhang, Yang & Ren , sp. nov. ( Figs. 9–10 ) Diagnosis. Flagellum bristle-like; vein Rs1 about twice as long as vein Rs2; vein R2+3 arising slightly distal of base of cell d; vein R2+3 ending at vein R1 far before wing margin; crossvein r-m nearly located at middle of cell d. Etymology. The specific name refers to the Latin: antiquus (ancient). Holotype . CNU-DB-NN2007007, female, 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 16 mm ; wing length 7.2 mm , wing width 2.3 mm . Head subround, slightly narrower than thorax. Eyes large, bare; ommatidia visible clearly. Flagellum bristle-like. FIGURE 9. Calosargus ( Calosargus ) antiquus sp. nov. Body with wing photograph in dorsal view. FIGURE 10. Calosargus ( Calosargus ) antiquus sp. nov. Camera lucida drawing, based on the original photograph, in dorsal view. Hind femur robust and distinctly swollen; tibia slender. Wing hyaline: Vein C ending at wing tip; veins C, Sc and R1 markedly thick; vein Sc long, extending beyond middle of wing. Vein R1 long and robust; vein Rs1 arising from middle of wing, about twice as long as vein Rs2; vein R2+3 arising slightly distal of base of cell d; vein R2+3 ending at vein R1 far before wing margin; veins R4 and R5 short; vein R5 ending far beyond apex of wing, relative lengths of veins Rs3, R4 and R5 about 6: 3: 4. Crossvein r-m nearly located at middle of cell d. Ve in M 3 absent, vein CuA1 arising from cell d. Vein CuP present. Cell sc wide open, mouth of cell sc about 3 times as wide as that of cell r4, mouth of cell r1 narrow, mouth of cell r4 about twice as wide as that of cell r1. Cell br nearly as large as cell bm. Cell d wide; base of cell m1 about 1/2 as wide as that of cell m2; mouth of cell m1 nearly as wide as that of cell m2. Mouth of cua1 wide open, about 5 times as wide as that of cell cup. Abdomen cylindrical, covered with setulae. Nine segments visible; segment I evidently short. Segments II to VII with distinct stria at side. Segments III to VI with wide black stripe at each end. Ovipositor tapering. Remarks. C. ( C. ) antiquus sp. nov. could be related to C. ( C. ) tatianae Mostovski, 1997 in the following aspects: vein Rs1 long, about twice as long as vein Rs2; vein R2+3 arising slightly distal of base of cell d; vein R2+3 ending at vein R1 far before wing margin; base of cell m1 about 1/2 as wide as that of cell m2. However, it can be easily separated from the latter by the shorter apical part of vein R1 (from ending of vein R2+3 to wing margin), shorter veins R4 and R5, wider crossvein r-m, and sharper base of cell d.