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 ) tenuicellulatus Zhang, Yang & Ren , sp. nov. ( Figs. 13–14 ) 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; relative lengths of vein R5 and vein Rs3 about 3: 5; crossvein rm located at basal 1/3 of cell d; cell d slender; base of cell m2 about 3.5 times as wide as that of cell m1; mouth of cell m1 nearly as wide as that of cell m2. FIGURE 13. Calosargus ( Calosargus ) tenuicellulatus sp. nov. Body with wing photograph in dorsal view. Etymology. The specific name refers to the Latin tenuis (narrow) and cellulatus (cell), referring to the slender cell d. Holotype . CNU-DB-NN2007009, an almost complete adult body with wing 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 10.7 mm ; wing length 9.0 mm, wing width 2.3 mm . Head round in dorsal view, slightly narrower than thorax. Eyes large, bare, holoptic; ommatidia visible clearly. Thorax black. Hind femur distinctly swollen; hind tibia slender, slightly longer than femur, first tarsomere of hind leg distinctly longer than following tarsomeres. Wing elongate, hyaline. Vein C ending at apex of vein R5; veins C and R1 markedly thick; vein Sc long, extending far beyond middle of wing. Vein R1 long and robust; vein Rs1 short, near 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; 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. Vein Cup present. Cell sc wide open, apex of cell sc about 3 times as wide as that of cell r4, apex of cell r4 about twice as wide as that of cell r1. Cell d slender, longer than vein M 1 in length; base of cell m2 about 3.5 times as wide as that of cell m1; apex of cell m1 slightly wider than that of cell m2. Cell cup narrow open, about 1/4 as wide as that of cell cua1. FIGURE 14. Calosargus ( Calosargus ) tenuicellulatus sp. nov. Camera lucida drawing, based on the original photograph, in dorsal view. Abdomen brown, slender, cylindrical; five segments visible. Segment I evidently short. Segments II to V with distinct stria at side. Segments III to V with wide black stripe at each end. Gender unknown. Remarks. C. ( C. ) tenuicellulatus sp. nov. could be related to C. ( C. ) daohugouensis sp. nov. in the following aspects: vein Rs1 short, nearly as long as vein Rs2; relative lengths of vein R5 and vein Rs3 about 3: 5; crossvein r-m located at basal 1/3 of cell d. However, it can be easily separated from the latter by the mouth of cell r4 about twice as wide as that of cell r1, cell d slender, longer than vein M 1 in length, base of cell m2 about 3.5 times as wide as that of cell m1, mouth of cell m1 slightly longer than that of cell m2. In daohugouensis , the mouth of cell r4 is about 4 times as wide as that of cell r1; cell d is wider, slightly shorter than vein M1; the base of cell m2 is about twice as wide as that of cell m1; the mouth of cell m1 is shorter than that of cell m2. Meanwhile, C. ( C. ) tenuicellulatus sp. nov. is also very similar to C. ( C. ) validus sp. nov. See the remarks of C. ( C. ) validus sp. nov. in detail.