Calosargus (Calosargus) tenuicellulatus 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 : 10-12

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.

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.

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.

Figures

FIGURE 13. Calosargus (Calosargus) tenuicellulatus sp. nov. Body with wing photograph in dorsal view.

FIGURE 14. Calosargus (Calosargus) tenuicellulatus sp. nov. Camera lucida drawing, based on the original photograph, in dorsal view.