Sharks (superorder Selachimorpha) are fish with a full cartilaginous skeleton and a highly streamlined body.
What’s older than sharks? Almost nothing. Sharks have been swimming in the ocean for more than 400 million years. They predate practically everything that has a spine, including humans and dinosaurs. – 100 Shark Facts
— Brasil_de_Ovelhas (@brasildeovelhas) February 7, 2017