What is a distinguishing characteristic of the members of the genus ambystoma?

Members of the genus Ambystoma, commonly known as mole salamanders, are characterized by their robust bodies, short limbs, and a distinctively broad, flattened head. They typically exhibit a smooth skin texture that can vary in color, often featuring bold patterns or markings. Additionally, many species within this genus undergo a unique life cycle, with some exhibiting a neotenic trait, retaining juvenile features into adulthood.