The mole salamanders are a group of advanced salamanders endemic to North America. The group has become famous due to the presence of the axolotl, widely used in research due to its paedomorphosis, and the tiger salamander which is the official amphibian of many US states, and often sold as a pet.
Mole salamander
Ambystoma kansensis (Adams 1929) fossil
Tiger salamander (Ambystoma tigrinum)
Phylogenetic tree showing relations among Ambystoma species and outgroups: For example, the sister taxon to Ambystoma macrodactylum is Ambystoma laterale, meaning they share a single common ancestor and are each other's closest living relatives.
The axolotl is a paedomorphic salamander closely related to the tiger salamander. It is unusual among amphibians in that it reaches adulthood without undergoing metamorphosis. Instead of taking to the land, adults remain aquatic and gilled. The species was originally found in several lakes underlying what is now Mexico City, such as Lake Xochimilco and Lake Chalco. These lakes were drained by Spanish settlers after the conquest of the Aztec Empire, leading to the destruction of much of the axolotl's natural habitat.
Axolotl
A captive leucistic axolotl, perhaps the most well known form of the axolotl
Face of a common or wild type axolotl
The speckled wild type form