Ahirmoneura Zhang, Yang, and Ren

Genus Ahirmoneura Zhang, Yang, and Ren View in CoL , nov.

Type species: Ahirmoneura neimengguensis Zhang, Yang, and Ren , sp. nov.

Derivation of the name: The generic name refers to the difference between the new genus and Hirmoneura .

Diagnosis. —Body large. Eyes large, dichoptic, ommatidia clearly visible. Wing elongate and rather narrow: Base of vein C swollen and sclerotized with dense setulae. Vein Sc short, ending slightly beyond middle of wing, far from level of fork of vein R 4+5. In apical part of wing, veins running parallel to anterior margin, ending before wing−tip. Vein R 3 absent; vein R 4 cambered basally. Crossvein r−m located at extreme base of cell d. Vein M 2 arising from apex of cell d; veins M 3 and CuA 1 fused before wing margin with a petiole. Vein CuA 1 arising from apex of cell d. Abdomen incomplete, 4 segments preserved. Segment I widest.

Remarks. —Judging from the wing venation, Ahirmoneura gen. nov. is similar to Hirmoneura Meigen, 1820 by having crossvein r−m present, vein M 2 reaching the anterior margin of the wing, veins M 3 and CuA 1 fused before wing margin with a petiole, alula broad. But, the new genus differs from Hirmoneura in vein Sc ending slightly beyond the middle of the wing, crossvein r−m at the extreme base of cell d, vein Rs distinctly longer than the distance between vein R 2 and crossvein r−m, vein M 2 arising from the apex of cell d, the mouth of cell r 1 over twice as long as that of cell r 2, cell r 4 longer than cell m 1, cell br much shorter than cell bm. In Hirmoneura , vein Sc is ending far beyond the middle of the wing, crossvein r−m is located at the apical part of cell d, vein Rs is distinctly shorter than the distance between vein R 2 and crossvein r−m, vein M 2 is arising from cell m 3, the mouth of cell r 1 is less than twice as long as that of cell r 2, cell r 4 is shorter than cell m 1, cell br is much longer than cell bm.

Key to genera of fossil (Jurassic) nemestrinid flies from China:

1. Crossvein r−m at extreme base of cell d; vein M 2 arising from cell d …..........……….......................................… Ahirmoneura

—. Crossvein r−m at apical part of cell d; vein M 2 arising from cell m 3 ………………................................................………. 2 2. Crossvein between veins M 1 and M 2 present; veins M 2 and CuA 1 + M 3 converged at a point at base ……… Florinemestrius —. Crossvein between veins M 1 and M 2 absent; veins M 2 and CuA 1 + M 3 diverged at base ……..….….……. Protonemestrius

Distribution.—The genus is known only from China and is currently represented by one species.