Palaeochrysa Scudder, 1883

Genus Palaeochrysa Scudder, 1883 View in CoL

Remarks. The genus Palaeochrysa was recently revised to include only one species P. stricta Scudder, 1890 from the late Eocene of Florissant ( Makarkin et al. 2022). Two more species in this genus are described below from the Kishenehn Formation. Makarkin et al. (2022) diagnosed the genus with the following characters: in the fore- and hind wings (1) two gradate series are present in the radial space; (2) inner gradate series is arranged in a strongly broken line; (3) Psm is nearly straight, slightly zigzagged; (4) Psm is formed by five branches of RP; in the forewing (5) im is elongate; and in the hind wing (6) three branches of CuA proximad fusion with MP. Two of the species ( P. stricta and P. greenwalti sp. nov.) share the whole set of these character states. The character states (2) and (4) are slightly different in P. minor sp. nov.: in this species the inner gradate series is arranged in a curved line, but not broken, and Psm is formed by three branches of RP (most likely related to its small size).

We found a new feature distinguishing Palaeochrysa from most other genera of Nothochrysinae . This genus possesses a proximal cell between two gradate series of crossveins in the hind wing (located at the termination of Psm; labelled gc 1 in Figs. 3C View FIGURE 3 and 4E View FIGURE 4 ). The cell is acute anteriorly as the very oblique crossvein of the inner series and a part of a RP branch (which are limited the cell anteriorly) coincide in the same direction, which continues the Psm. All gradate cells are principally similar in shape at least in other fossil genera from North America.

Therefore, the assignment of Palaeochrysa greenwalti sp. nov. to Palaeochrysa is undoubted, while P. minor sp. nov. is very probable.