Which of these were believed extinct but were discovered living in 1938?

The primitive-looking coelacanth (pronounced SEEL-uh-kanth) was thought to have gone extinct with the dinosaurs 65 million years ago. But its discovery in 1938 by a South African museum curator on a local fishing trawler fascinated the world and ignited a debate about how this bizarre lobe-finned fish fits into the evolution of land animals.

Source: National Geographic