In both Python and Aspidites, 2n = 36. In Boa 2n = 36 too, but in Acrantophis 2n = 38. Therefore, while Python regius and Aspidites ramsayi are genetically compatible (as weird as this may seem), Boa constrictor and Acrantophis dumerilli are not. Sure, based on morphometrical similarity you'd expect things to be the other way around, but morphometrical similarity doesn't always imply genetic compatibility.