This is something I've been trying to understand lately myself. The reason for all the changes is genetic research, ie molecular taxonomy. The old way to classify animals was to describe them physically. Scale counts, head structure, body structure, colors, patterns, etc. The new way is through genetic testing, specifically to trace evolutionary paths via computer modeling. At least that is how I understand it.
Here is a basic rundown of whats going on:
A Brief Look At Reptile Taxonomy
Here is the big paper laying down the groundwork for
Pantherophis and to a lesser degree
Pituophis. There is another big paper by the same biologists (most notably Frank T. Burbrink) building further on this paper in regards to
Pantherophis but I can't seem to find it without buying it.
Here is the paper on
Lampropeltis, specifically Milk Snakes.
Here is the paper on
Lampropeltis, specifically Kingsnakes.
Rat Snakes (Rats/Corns/Foxes) and Pits (Bulls/Gophers/Pines) are very different physically. Rats are slender relative to Pits. Rats have a very flat, well defined belly that along with a prehensile tail makes them excellent climbers. Pits are heavy bodied snakes that tend to stick to the ground. Pits have a larger head and a much more powerful bite to go along with it, they also have a very prominent rostral scale they use to dig around in leaf litter and soil. I find the easiest way to learn to spot the differences between snakes is like learning most anything, practice. Google pictures of Rat Snakes and look at dozens and dozens of them. Look at Rats Snakes until you can see them with your eyes closed. Then Google Pits. The odds are you'll notice differences right away.
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