Not really sharks at all, but the earliest vertebrates with jaws that we know about.

Evolution of the early vertebrates.

Tunicates are sessile, but their larvae are mobile, and have some features found in early vertebrates.

The earliest vertebrates, which were types of jawless fish, lived in saltwater about 500,000,000 years ago.

All of these early vertebrates lacked jaws in the common sense and relied on filter feeding close to the seabed.

New evidence on the anatomy and phylogeny of the earliest vertebrates.

Pterosaurs are the earliest vertebrates known to have evolved powered flight.

It is now clear that these genes did not, in fact, arise in early vertebrates.

Dmitry Obruchev, a paleontologist, was a leading authority on early vertebrates.

Smells lie deeper than our remembering, thinking forebrains, in the olfactory lobe we inherited from the early vertebrates.