Hybrid talk

[DennisM]

... these two subspecies also happen to intergrade in the wild where their ranges overlap.

and maybe more to the point, there are well established populations of what the pet trade calls DCI (Diamond Coastal Intergade). these are not the result of a diamond mating with a coastal. they are a distinct population that is made up of DCIs. maybe they're not DCIs at all. some would say morelia spilota is morelia spilota and these three (diamond, coastal and DCI) are just regional variations of the same thing that have adapted to differing ecosystems over millennia. for all we know the snakes we consider to be the intergrades may well be the founding race.