What’s the difference between a newt and an axolotl?
A newt is a salamander but not all salamanders are newts.
There are 9 different families of salamanders and the family Salimandridae contains all of the various newt species.
The axolotl is a member of the family Ambystomatidae, which includes many different types of mole salamander.
To lean more:
Zhang P, Wake DB. 2009. Higher-level salamander relationships and divergence dates inferred from complete mitochondrial genomes. Mol Phylogenet Evol 53: 492–508.
Maden M. Axolotl/newt. 2008. Methods Mol Biol. 461:467-80.