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] A shark, also called a "selachimorph", can be described as all of the following: List of sharks Subdivisions of the biological classification Selachimorpha include: Shark attack Sharks in captivity