Genus Quadraticossus Wang & Ren, 2007

2007 Quadraticossus Wang Y & Ren, p. 41.

Type species. Quadraticossus fangi Wang & Ren, 2007

Revised diagnosis. Forewing triangular. Sc separated from R at wing base, and then fused with R, extending to near indentation and terminating on R1. Rs simple. M 4-branched, M4 sharply flexed after arising from M3+4. CuA connected with M4 by horizontal crossvein. Nodal line dividing discal cell into two parts, 2nd discal cell nearly rectangular.

Hind wing small, with distinct costal indentation. Sc parallel to R at base, fused with R for short distance, terminating near indentation. M 3-branched, stem of M1+2 long, and M3+4 unbranched. Crossvein m3+4-cua short. Anal vein single.

Species included. Q. fangi Wang & Ren, 2007; Q. longicaulis Wang & Ren, 2007; Q. eumorphus sp. nov.

Remarks. This genus established by Wang Y & Ren (2007a) was based on a body with a pair of forewings and hind wings and a single forewing from the Middle Jurassic of Daohugou, Inner Mongolia, China. The diagnostic characteristics of the hind wing can be seen clearly from the material described here: Sc and R separated at base, fused at point of origin of Rs, then Sc coalesced with R1+2 for short interval before extending to costal margin at indentation.