This is the only confirmed location for this species, but a wider distribution is probable.
Further differences are present as well.
Worthy to check the picture. This is Kullander's paper containing A. meinkeni's original description, as well as many other species. I agree with what Mike Wise suggested, i.e., that A. pertensis is not a single, but a complex of species. It's a fish from Rio Negro. I've collected some fishes like A. meinkeni, as the so-called A. cf.