are mexican salamanders a kind of neotenic salamanders

Yes, Mexican salamanders, especially the Axolotl (Ambystoma mexicanum), are indeed a type of neotenic salamander. Neoteny is a biological phenomenon where an organism retains its juvenile features into adulthood.

The Axolotl is a classic example of neoteny among amphibians. Despite reaching sexual maturity, it retains its larval characteristics such as external gills, a rounded body, and a markedly different appearance from the adults of most other salamander species which undergo metamorphosis to transform into terrestrial adults. Axolotls remain aquatic throughout their entire life, unlike many other salamanders that metamorphose to become better adapted to land environments.