If you consider that the ancestors of Vieja, may be from the Heros line the migrated north, when the land gap between north and south America was filled in in Panama umpteen million years ago by volcanic action, and with the teutonic plates colliding providing a bridge, It doesn't seem that far fetched, that the two genera would see each other as distant cousins, although quite removed.
I have a theory running thru my head, that the cichlid Isthmoheros tuyrense of the Darian gap, (thought to be once a part of the genus Vieja) is the missing link between the genera of once separate continents.
One of the reasons I moved to Panama was to explore the species stalled in that land gap.
The first I studied was Andinoacara coerleopunctatus, the only Andinoacara to migrate into both Central America, and still retain its genus status.
I caught this one recently in a river in Panama.