The Amboina sail-finned lizard or Amboina sailfin lizard (Hydrosaurus amboinensis) is the largest agamid lizard in the world, growing to over one metre in length. It is found in Papua New Guinea, Indonesia, and the Philippines. Due to confusion with H. pustulatus, its exact distribution in the Philippines is uncertain, but northern populations are generally considered H. pustulatus and southern considered H. amboinensis. This lizard is able to run short distances across water using both its feet and tail for support, an ability shared with the plumed basilisk.