Paramesosciophilodes bellus Gao, Shi, Shih & Ren

Gao, Jiaqi, Shi, Guifeng, Shih, Chungkun & Ren, Dong, 2015, Two new species of Paramesosciophilodes (Diptera, Nematocera, Mesosciophilidae) from the Middle Jurassic of China, ZooKeys 511, pp. 117-129 : 121

Taxon classification Animalia Diptera Mesosciophilidae

Paramesosciophilodes bellus Gao, Shi, Shih & Ren sp. n. Figs 1, 2

Etymology.

The specific name is from the Latin of bellus, meaning beautiful and delicate, for the well-preserved and beautiful specimen.

Material.

Holotype No. CNU-DIP-NN2013631 p/c, part and counterpart. A well-preserved insect with complete body and two wings but poorly preserved halter, without head, in dorsoventral aspect.

Locality and horizon.

Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China, Jiulongshan Formation, late Middle Jurassic.

Diagnosis.

The Sc1 ending proximad of the midlength of cell r; bRs 0.7 times of the length of r-m; R4+5 strongly curved; M1+2 forking basad of forking of Rs, and distad of the level of Sc1 ending; CuA strongly arched, reaching the posterior margin of the wing markedly basad of Rs forking to R2+3 and R4+5.

Description of holotype.

Medium-sized mesosciophilid with dark body, adult male, in dorsal aspects (Figs 1 and 2A). Wings out-spread, length 5.4 mm, width 2.0 mm. Body length 7.2 mm. Head and antennae not preserved. Thorax convex, length 2.0 mm, width 1.3 mm. Scutellum clearly projecting. Abdomen thin, subcylindrical, length 5.2 mm, width 1.7 mm, approx. 2.6 times as long as head and thorax combined, with eight abdominal segments, first four segments gradually widened distally, last four segments gradually narrowed terminally. Partially preserved male genitalia relatively small, distinctly narrower than eighth abdominal segment. Halters poorly preserved. Legs relatively thin and long, femora clearly thicker in the middle; femora, tibiae and tarsi with two rows of sparse and short setae. Hind leg length 6.3 mm (femur 1.7 mm, tibia 2.4 mm, tarsus 2.2 mm).

Wings membranous, oblong, darker in color in costal area, moderately wide (length 2.7 times of width), and not reaching the apex of abdomen at rest (Fig. 2). C strong, ending beyond wing apex, at which R4+5 ending. Sc1 relatively long, approx. 0.4 times the length of wing, ending far distad of the intersection of bRs and r-m. Humeral vein distinct and oblique. Sc2 well developed, starting in front of bRs. Cell r distinctly small (0.89 mm), approx. 0.165 times the wing length (5.4 mm). Section of R from Sc2 to bRs origin approx. 2.4 times as long as bRs. R forking into three branches: R1, R2+3 and R4+5. R1 and R4+5 somewhat divergent terminally; R2+3 and R4+5 arched. Forking of Rs distad of the level of M forking. Rs strong, arising from beyond the basal one-third of length of wing, bRs+dRs nearly 0.4 times the R4+5. Rs forking to R2+3 and R4+5 distad of forking of M1+2. Section bRs 0.7 times the r-m. R1 slightly curved, relatively long (nearly 0.5 times the length of wing), slightly deflected after junction with R2+3; R2+3 slightly curved, shifted toward wing base, beyond the level of M1+2 forking. Vein R4+5 strongly arched near its midway, almost parallel with R1, but slightly oblique at apex. Stem of M completely reduced basad of crossvein m-cu, with only a short segment distad of m-cu. Stem of M forking into M1+2 and M3+4. M1+2 forking into M1 and M2 near R2+3 level. M1 arched anteriorly, M2 nearly straight. Crossvein r-m short, curved, slightly oblique, shorter than bRs, nearly perpendicular to M1+2, almost parallel to R2+3, intersected at M1+2, forking to bM1+2 and dM1+2. bM1+2 approx. 6.6 times as long as m-cu. dM1+2 approx. as long as bM1+2, and longer than r-m. CuA running parallel close to M3+4 basally. CuA reaching the posterior margin of wing at approx. the same level of M1+2 forking to M1 and M2. CuP short, slightly curved at its midway, not reaching the posterior margin of wing.

Remarks.

Paramesosciophilodes bellus sp. n. resembles most closely Paramesosciophilodes ningchengensis , but can be distinguished from the latter in having Sc1 ending at C proximad of the miglength of cell r (vs. at the miglength of cell r for Paramesosciophilodes ningchengensis ) and CuA reaching the posterior margin of the wing markedly basad of Rs forking to R2+3 and R4+5 (vs. slightly basad of Rs forking to R2+3 and R4+5).

This new species is differentiated from Paramesosciophilodes ningchengensis , Paramesosciophilodes eximia , Paramesosciophilodes aequus , and Paramesosciophilodes rarissima sp. n. based on a combination of characters listed in Table 2.