Fossils index

Cartilaginous fish

Cartilaginous fish have skeletons of cartilage rather than bone. They live in the sea. They include sharks and rays.

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Chondrichthyes
Subclass: Elasmobranchii
Cartilaginous fish are vertebrates like us. However, they have a skeleton made of cartilage rather than bone. This means that their teeth are the most likely part to be fossilised.

The shark tooth is the state fossil of Georgia, USA.

Shark tooth

Timescale: Cartilaginous fish have been around for a long time, about 440 million years ago, and are still alive today.


Shark

In Japan, shark teeth were considered to be Tengu-no-Tsume, or Tengu finger nails. A tengu is a monster with a long nose. Sometimes Tengu resemble a bird of prey. Perhaps the shark teeth looked like bird claws.

Shark teeth used to be called Glossopetra or tongue stones. Pliny the Elder mentions them. In Malta, there is a legend that St Paul removed the tongues from snakes after he was bitten by a snake. Many 'tongue stones' were found in Malta, and these were supposed to be the tongues of snakes which had been turned to stone. They were considered to be an antidote to poison.

In 1666, Steno, a physician interested in the natural sciences, examined a shark. This convinced him that the co-called tongue stones were in fact shark teeth. But there were differences, so he concluded that tongue stones had to be the teeth of ancient sharks which no longer existed. He also realised that since these fossils were found on land, the sea must have covered the land in the past.


Shark

In many shark species, the teeth are replaceable. Some sharks can lose 30,000 teeth in a lifetime. All sharks have multiple rows of teeth. This explains why there are so many shark teeth fossils.

Until the 16th century, sharks were known to mariners as 'sea dogs'. The name 'shark' first came into use after Sir John Hawkins' sailors exhibited one in London in 1569 to refer to the large sharks of the Caribbean Sea, and later as a general term for all sharks. Today, there are still small sharks called dogfish.

A collection of shark teeth, including a tiny one. Sizes: 7mm-20mm
Shark teeth

Shark teeth

These shark teeth were collected from Bracklesham Bay, near Chichester.

Size: 20mm (left) 35mm & 15mm (right)

Shark teeth

This tooth belonged to a Crow Shark (Squalicorax Pristodontus). The Crow Shark was a predator and lived during the Cretaceous Period. It fed on turtles, fish and other sea creatures. This specimen was found in Morocco. The photos show top and underneath.

Size: 27mm

Corax tooth
Corax tooth

Live ray Rays are also cartilaginous fish. Here is a ray tooth from Morocco, about 50 million years old, top and side.
Size: 22mm

Ray tooth
Ray tooth


These two rays' teeth was collected from Bracklesham Bay, near Chichester. They are shown from two sides.Sizes: 15mm

Shark teethShark teeth Shark teethShark teeth