That is a good question and I will try to answer from collected info:
22 years ago when the real A. rivulatus was in the hobby, the name Green terror never excisted.
When silver/gold saum arrived, they became more popular (more color, bigger, but less agressive), and the name Green terror was born, i.e. Green terror=silver/gold saum=A. sp Rivulatus.
A. sp Rivulatus became very popular. The fish got the name Green Terror from salesmen. The "Green Terror" is A. sp rivulatus Gold saum and Siver saum, not A.Rivulatus. The 'true' A.Rivulatus originates from the Andes in Peru.
Thanks to Jeff Rapps, A.Rivulatus are in the hobby again.