Which marine reptile is the only seagoing lizard?

The marine iguana is the only modern lizard that routinely forages in the sea.

Marine iguanas are endemic to the Galápagos Islands, where they feed mainly on algae growing on submerged rocks. They dive using their flattened tails for propulsion and can cling to rocks with sharp claws while grazing. After feeding, they bask on land to raise their body temperature because seawater rapidly cools them.

These reptiles have special adaptations for marine life. Salt glands near the nose remove excess salt, which is expelled in forceful sneezes. Their dark coloration also helps them absorb solar heat after cold dives.

Marine iguanas are still lizards, not marine snakes or turtles. They spend much of their lives on land, but their regular underwater feeding makes them unique among living lizards.