Updated key to Chinese species of Ankylopteryx (s. str.) by Ma et al. (2020)

1. First intramedian cell very long and narrow................................................................. 2

- First intramedian cell short and wide...................................................................... 4

2. Frontal area between antennae with three black spots; scape and pedicel with brownish stripes.... A. gracilis Nakahara, 1955

- Frontal area between antennae immaculate; scape and pedicel immaculata........................................ 3

3. Both wings with yellowish marking patterns........................................ A. ferruginea Tsukaguchi, 1995

- Both wings with brownish marking patterns........................................... A. doleschalii Brauer, 1864

4. Frontal area between antennae with markings............................................................... 5

- Frontal area between antennae without markings............................................................ 6

5. Frontal area between antennae with three spots; hind margin of both wings without a large brown mark in the anal section.............................................................................. A. yangi Ma, Yang & Liu, 2020

- Frontal area between antennae with two spots; hind margin of both wings with a large, dark brown, irregular shaped mark along posterior margin near the base of the wing, including the anal wings........................ A. delicatula Banks, 1937

6. Hind margin of both wings with a large brown mark, not near base, extending over five marginal veins.............................................................................................. A. magnimaculata Yang, 1987

- Hind margin of both wings without brownish band........................................................... 7

7. Frons usually with large and broad reddish stripe below toruli; entoprocessus sinuous medially............................................................................................ A. octopunctata candida (Fabricus, 1798)

- Frons with narrow reddish stripe below toruli; entoprocessus not sinuous medially.................................. 8

8. Large species (forewing Ẑ 14 mm); wings with extremely distinct markings (Fig. 2A).............. A. rubrocincta sp. nov.

- Smaller species (forewing ± 13 mm); wings with indistinct markings (Fig. 1A)...................... A. diffluens sp. nov.