Both salamanders and lizards have much in common regarding their appearance. Although they have evolved a primitive tetrapod physique, they are related to toads and frogs, not lizards. All salamanders and nearly all lizards are quadrupedal, although lizards tend to be more agile than their amphibian counterparts.
They share a common characteristic - when in danger, both lizards and salamanders can shed their tails. This is where the similarities end.
Because of their slowness and clumsiness, salamanders have evolved different defensive strategies than lizards. Their slippery flesh helps them escape the predator's grasp. They also use chemical defenses as they have glands that produce toxins. Most of the time, the attacked salamander positions itself with its back to the attacker, as most of the venom-producing glands are located in the tail area.
Lizards have evolved many different strategies that vary from species to species. For example, some can outrun an attacker, play dead, puff up their body to prevent the predator from swallowing, deliver a venomous bite, or even squirt blood from pouches located above their eyes to confuse their opponent.
Despite their similar appearance, these animals are very different with respect to other criteria.
The first salamanders appeared on Earth in the middle Permian period, about 270 million years ago. First known lizard fossils, which were iguana-like creatures, date back to the middle Triassic age about 220 million years ago. That means salamanders lived on Earth about 50 million years longer than lizards. Although their head start in time, salamanders have not managed to diversify as much. Currently, there are about 655 species of salamanders and as many as 4,675 species of lizards.