Key to subgenera and species of Chinese Goniagnathus Fieber (males)

1. Pygofer side without appendage. Fused subgenital plates and valve elongate. ..................... G. (Epitephra) rugulosus

- Pygofer side with or without appendage. Fused subgenital plates and valve short...................................................... 2

2. Pygofer side without appendage. Style apophysis with apex strongly oblique, subapical lobe well-developed. .......... ................................................................................................................................................ G. (Goniagnathus) brevis

- Pygofer side with dorsocaudal appendage present. Style apophysis with apex not strongly oblique, subapical lobe moderate to weakly developed. G. (Tropicognathus).................................................................................................... 3

3. Style apophysis expanded apically (Fig. 1 C)................................................................................................................ 4

- Style apophysis similar in width throughout length. .................................................................................................... 5

4. Pygofer side constricted at mid-length and broadened caudally. Aedeagal shaft strongly curved caudodorsad and in apical 0.25 strongly curved anteriorly, not bifid apically. ............................................................................ G. nervosus

- Pygofer side with caudal lobe rounded (Fig. 1 A). Aedeagal shaft arcuate, bifid apically (Figs 1 D, 1E). ..................... ..................................................................................................................................................... G. viraktamathi sp. n.

5. Pygofer side appendage elongate. Aedeagal shaft in lateral view with pair of apical linear processes. ...................... 6

- Pygofer side appendage robust. Aedeagal shaft in lateral view with pair of apical triangular processes. ... G. cornutus

6. Lower aedeagal processes situated at midlength of shaft. ........................................................................... G. punctifer

- Lower aedeagal processes situated slightly basad of midlength of shaft. ................................................... G. taiwanus