Hydrosaurus, commonly known as the sailfin lizards, is a genus in the family Agamidae. These relatively large lizards are named after the sail-like structure on their tails. They are native to the Philippines, Indonesia, and Papua New Guinea, where they are generally found near water, such as rivers. They are the only members of the Hydrosaurinae subfamily.

Hydrosaurus, commonly known as the sailfin lizards, is a genus in the family Agamidae. These relatively large lizards are named after the sail-like structure on their tails. They are native to the Philippines, Indonesia, and Papua New Guinea, where they are generally found near water, such as rivers. They are the only members of the Hydrosaurinae subfamily.