The following outline is provided as an overview of and topical guide to sharks:
Sharks (superorder Selachimorpha) are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 440 million years ago, before the time of the dinosaurs.[1]
- ^ Martin, R. Aidan. "Geologic Time". ReefQuest. Retrieved 2006-09-09.