Paramesosciophilodes rarissima 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 : 121-123

Taxon classification Animalia Diptera Mesosciophilidae

Paramesosciophilodes rarissima Gao, Shi, Shih & Ren sp. n. Figs 3, 4

Etymology.

The specific name is from the Latin word of rarissimus, meaning rare.

Material.

Holotype No. CNU-DIP-NN2013145 p/c, part and counterpart. A well-preserved insect with complete body with two wings, without head and halters, in dorsoventral aspect.

Locality and horizon.

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

Diagnosis.

Sc1 ending near the midlength of cell r; bRs 0.8 times the r-m; R4+5 strongly curved; M1+2 forking basad of R2+3 level and distad of level of Sc1 ending at C; CuA strongly arched, reaching the posterior margin of the wing at the level of intersection of Rs forking to R2+3 and R4+5.

Description of holotype.

Medium-sized mesosciophilid gnats, in dorsal aspect (Figs 3 and 4A). Body length (without head and part of thorax) 7.2 mm as preserved. Legs covered with long, dense pubescence. Head, antennae, and halters not preserved. Thorax length 1.8 mm, width 1.5 mm. Mesonotum convex. Scutellum sharp, clearly projecting. Wings membranous, oblong, length 5.0 mm, width 2.2 mm, darker in color in costal area, length 2.3 times width, and not reaching the apex of abdomen at rest. Abdomen thin, subcylindrical, length 5.4 mm, width 1.5 mm, with first five segments gradually widened distally, other segments gradually narrowed terminally. Legs poorly preserved, femora thicker in the middle, covered with numerous setae.

C strong, ending beyond wing apex, at which R4+5 ending (Fig. 4). Sc converging with C before the level of R4+5. Sc1 elongate, slightly shorter than one-half of wing length (0.43-0.47 times the wing length), and ending far distad of the intersection of bRs and r-m. Vein h distinct and oblique. Sc2 developed well, starting in front of Rs, situated distinctly basal to Rs origin, arising beyond midway between h to Sc1 ending. Cell r relatively large (0.92 mm), approx. 0.18 times the wing length (5.0 mm). The section of R from Sc2 to Rs origin approx. 0.7 times the section bRs. R forking to R1 and Rs, then Rs to R2+3 and R4+5. Both R1 and R4+5 somewhat divergent terminally; R2+3 and R4+5 arched. Rs usually strong, arising from basal one-half of length of wing, forking to R2+3 and R4+5 beyond the forking of M1+2. Section bRs 0.8 times the r-m. R1 slightly curved, relatively long, nearly 0.5 times the wing. Both R1 and R4+5 divergent terminally. R2+3 curved, beyond the level of M1 and M2 forking. R4+5 strongly arched near its midlength. Stem of M, basad to crossvein m-cu completely reduced, with only a short segment distal to m-cu. Stem of M forking into M1+2 and M3+4. M1+2 forking into M1 and M2 basad of R2+3 level and distad to level of Sc1 ending at C. M1 arched cephalad. M2 nearly straight. Crossvein r-m short, curved, slightly oblique, shorter than bRs, r-m intersecting M1+2 and dividing M1+2 into bM1+2 and dM1+2. Section bM1+2 approx. 4.3 times the crossvein m-cu. Section dM1+2 approx. 1.2 times the section bM1+2, and longer than r-m. CuA running parallel and close to M3+4 basally. CuP short, slightly curved midway, reaching the posterior margin of wing at the same level as Sc1 ending at C.

Remarks.

Paramesosciophilodes rarissima sp. n. is distinguished from all other species of Paramesosciophilodes based on a combination of characters listed in Table 2.