Axolotls are members of the mole salamander family (Ambystomatidae), along with the tiger, spotted, Jefferson, Blue spotted, marbled and others. I don't think they can breed with tiger salamanders though. Mudpuppys belong to the Necturus family.
Axolotls aren't mudpuppies, I believe they are really closely related. Though as I understand it they are closer to tiger salamanders and can actually breed with tiger salamanders.
I agree with sand tiger. Hell benders are EXTREME. There like something you'd run into during the time of the dinosaurs. Sanchez, your thinking about the Chinese and Japanese Giant salamanders, Andrias davidianus and Andrias japonicus respectively. These things are true monsters.
~76