It is highly unlikely that the fish sold as G. cf. altifrons "Aripuana I" in Australia is actually an altifrons. The fish in question has a large lateral spot and a highly striped caudal fin which are not characteristics of G. altifrons. These so called Ari I's are very likely a variant of Geophagus abalios. Please remember that this does not change the value or beauty of these fish in any way.
Interestingly, there seems to be a severe lack of pictures on the internet of G. cf. altifrons "Aripuana I and II". Here is the one and only picture on the internet of a G. cf. altifrons from the Rio Aripuana, which in reality looks to be a G. cf. argyrostictus "Aripuana". Weidner's book has three images of G. cf. altifrons "Aripuana I" and only one of G. cf. altifrons "Aripuana II".