Palaeothyridosmylus, Wang, Yongjie, Liu, Zhiqi & Ren, Dong, 2009

Wang, Yongjie, Liu, Zhiqi & Ren, Dong, 2009, A new fossil lacewing genus from the Middle Jurassic of Inner Mongolia, China (Neuroptera: Osmylidae), Zootaxa 2034, pp. 65-68 : 65

Palaeothyridosmylus gen. nov.

Type species. Palaeothyridosmylus septemaculatus sp. nov.

Diagnosis. Membrane fuscous, with some fenestrated spots. Nygmata distinct at the center of wing. Costal crossveins simple and forked occasionally. Rs with numerous branches, cross-veins in radial sector arranged irregularly, and not forming the gradate cross-veins. MP forked close to the base of wing, MP2 with pectinate distal branches. Cu forked at wing base, Cu2 also with pectinate distal branches. Cross-veins between MP and Cu more than one, and not forming free space. Anal area well developed, A1 with numerous pectinate branches from its middle to wing margin; A2 short, but also with some distal pectinate branches.

Etymology. The new genus name is a combination of the Greek palaeo- and Thyridosmylus (a genus of Osmylidae ). The gender is masculine.

Discussion. Although the new genus shares some characters of both Thyridosmylus and Thaumatosmylus , it also shows some special venational features which can confirm their new generic status: cross-veins in radial sector irregularly organised, and not forming the gradate series, while the other genera of the subfamily have at least the outer gradate series; more than one cross-vein between MP and Cu more than one, and without the free space. Although New (1991) thought that the number of mp-cu cross-veins is variable, we consider that this feature can be used for intergeneric identification. The cross-veins always are missing in Thyridosmylus , Glenosmylus , Lysmus and Spilosmylus , but only one in Thaumatosmylus . Cu branches with equal length, while Cu2 is generally shorter than Cu 1 in extant Spilosmylinae. The anal region is also well-developed, which is commonly reduced in extant species. Furthermore, these features are regularly found in other fossil Osmylidae , thus, we consider the complicated cross-veins in radial sector and the dilated anal region probably represent the ancestral characters in Osmylidae .