Similsciophila sinuata, Shi & Shih & Ren, 2014

Shi, GuiFeng, Shih, ChungKun & Ren, Dong, 2014, A new genus with two new species of mesosciophilids from the Middle Jurassic of China (Diptera: Nematocera: Mesosciophilidae), Journal of Natural History 49 (19), pp. 1147-1158 : 1154-1156

Similsciophila sinuata sp. nov.

( Figures 4A–D )

Diagnosis

Wing membranous 2.2 times as long as wide; R 2+3 strongly curved, and usually strongly sigmoid; bRs long and about 2.0 times as long as r-m; dM 1+2 about 1.3 times as long as bM 1+2; bM 1+2 about 5.8 times as long as m-cu.

Material

Holotype No. CNU-DIP-NN2011511 , an incomplete body with two wings and a haltere, in lateral aspects .

Etymology

The specific name is from the Latin (sinua-), meaning that vein R 2+3 is more arching.

Locality and horizon

Late Middle Jurassic, Jiulongshan Formation, Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China ( Ren et al. 2010).

Remark

This new species is differentiated from Similsciophila singularis gen. et sp. nov. by the following characters: (1) R 2+3 of the new species is strongly curved, and usually strongly sigmoid (versus slightly curved, almost perpendicular to R 4+5); (2) the ratio of bRs and r-m of the two species is diverse (2.0 versus 1.1–1.4); (3) the ratio of dM 1+2 and bM 1+2 of the two species is different (1.3 versus 1.4–1.8); (4) the ratio of bM 1+2 and m-cu of the two species is dissimilar (5.8 versus 2.0–2.4).

Description

Mesosciophilid gnats medium-sized, in lateral aspects. Wings outspread. Head poorly preserved. Antennae well-preserved, 13-segmented, longer than head, with all flagellomeres oblong and nearly the same size in length and width. Body covered with long dense pubescence. Mesonotum convex, scutellum sharp and clearly projecting. Abdomen incomplete preserved. A haltere well-preserved, spatulate, and its inner margin a bit straight. Legs thin long, clavate, and covered with two rows of sparse and short setae.

Wing membranous, oblong, darker in colour in costal area, 2.2 times as long as wide, and not reaching apex of abdomen at rest. C strong, ending beyond wing apex, at which R 4+5 ending. Sc relatively long, about 0.4 times as long as wing, and ending far distal to crossing of bRs and r-m. h distinct. sc-r well developed, arising near midway between h to Sc ending at margin, and situated distinctly basal to Rs origin. Cell r distinctly large, longer than one-sixth of wing length, and nearly 0.2 times as long as wing length. The section of R from sc-r to Rs origin about 1.6 times as long as bRs. R furcated to three branches. R 1 slightly curved, relatively long, and about 0.6 times length of wing. R 1 and R 4+5 running divergent terminally. Rs robust, arising from less than basal one-third of length of wing, furcated basal near to midwing to R 2+3 and R 4+5, and nearly 0.4 times as long as R 4+5. bRs distinctly long, and 2.0 times as long as r-m. R 2+3 arched, strongly curved, and usually strongly sigmoid, beyond level of M 1+2 forking, almost perpendicular to R 4+5. R 4+5 strongly arched near its midlength. R 4+5 and M 1 arched and subparallel. r-m short, slightly oblique, furcated M 1+2 to bM 1+2 and dM 1+2, and shorter than dM 1+2. Veins of bM 1+2 and r-m forming nearly a right angle. dM 1+2 about 1.3 times as long as bM 1+2. M furcated to M 1, M 2 and M 3+4. Stem of M not developed, thin, and usually thinner than its branches. Forking of M beyond level of forking of Rs. M 1+2 furcated slightly distad to level of Sc ending. M 1 arched upwards, and subparallel to R 4+5. M 2 almost straight. bM 1+2 about 5.8 times as long as m-cu. CuA running close to M 3+4 basally, but neither coalescent. A slightly curved at its midway, ending far from posterior margin of wing.

Dimensions (mm)

CNU-DIP-NN2011511: Body length 6.6 (antenna length 2.0, width 0.1; thorax length 1.6, width 1.0; abdomen length 5.0, width 1.3); wing length 4.6, width 2.2; hind leg length 7.0 (femur length 2.2, tibia length 2.9, tarsus length 1.9).

Figures

Figure 4. Similsciophila sinuata sp. nov., holotype, CNU-DIP-NN2011511. (A) Photograph of habitus (lateral aspect); (B) photograph of wing part; (C) line drawing of habitus; (D) line drawing of wing venation.