What is a defining feature of the green salamander's toes?

The defining feature of the green salamander's toes is that they are square-tipped and expanded. This unique toe morphology is an adaptation that aids in climbing and gripping onto surfaces, which is particularly helpful for a species that often inhabits rocky or arboreal environments. The expanded tips provide a better surface area for traction, allowing the salamander to navigate its habitat more effectively. This characteristic distinguishes the green salamander from many other amphibians, which may have more slender or pointed toes that are not as well-suited for climbing.

The other options describe features that are not typical of the green salamander. For example, slender and pointed toes or thick and short toes do not support the climbing behavior that is crucial for this species. While some amphibians do have webbed toes for swimming, this is not applicable to the green salamander, as they are primarily terrestrial or arboreal and do not rely on swimming as their main mode of locomotion.