Ambystomatidae

Ambystomatidae is a family of salamanders belonging to the Suborder Salamandroidea, comprising predominantly terrestrial species found across North America. This family is distinguished by its two genera: Ambystoma, commonly known as mole salamanders, which includes 32 species, and Dicamptodon, the Pacific giant salamanders, with four species. These amphibians are characterized by their robust build, featuring chunky bodies, broad and flat heads, short legs, and long, flattened tails. Their skin is smooth and shiny, with coloration typically ranging from black, brown, or dull grey, often adorned with speckles or spots.

Habitat and Distribution

Ambystomatids are widely distributed throughout the United States and extend into parts of Canada, preferring habitats such as damp forests, plains, temperate forests, and wetlands. While primarily terrestrial, adults often create burrows and emerge to reproduce in water bodies or streams, typically in early spring. They are nocturnal by nature, though they can be found active on cooler days beneath moist leaf litter, logs, or rocks near aquatic environments.

Characteristics and Behavior

Adult ambystomatids generally lack gills and moveable eyes, possessing well-developed lungs. A notable characteristic of some species within this family is neoteny, where individuals retain larval features, such as gills, throughout their adult lives, with the axolotl being a prominent example. For defense, some species are capable of secreting toxins from their bodies to ward off predators or deter intraspecific competition. Reproduction involves internal fertilization, with males performing a courtship display in water before depositing spermatophores. The larval stage typically lasts for three to four months.

Taxonomy

Historically, the genus Rhyacotriton was included in the Ambystomatidae family. However, it is now commonly placed in its own distinct family, Rhyacotritonidae. More recently, cladistic analyses have led to the reclassification of Dicamptodon back into the Ambystomatidae family. This family is recognized for containing some of the largest terrestrial salamanders found globally, including the tiger salamander and the coastal giant salamander.