Main differences between Vipera aspis aspis and Vipera aspis zinnikeri

1- Size: Vipera aspis aspis is slightly larger than Vipera aspis zinnikeri.

2- Colouration: The zigzag pattern is thicker in Vipera aspis zinnikeri. The ground colour is more variable in the zinnikeri subspecies.

3- Head: The tip of the snout is less prominent in Vipera aspis zinnikeri. The frontal and parietals are more fragmented in Vipera aspis aspis.

4- Pholidosis: The number of subcaudals is lower in the zinnikeri subspecies. The number of scale rows between the eye and the supralabials is more variable in Vipera aspis zinnikeri (1, 1,5 or 2 rows) while Vipera aspis aspis usually has two rows.

5- Venom: The venom of Vipera aspis zinnikeri is two to four times more toxic than that of Vipera aspis aspis.