Edaphodon kawai facts for kids

Edaphodon kawai was an ancient fish that lived long ago. It was a type of chimaeriform fish, also known as a rabbitfish. All species in its group, Edaphodon, are now extinct.

Rabbitfish are special because they are cartilaginous fish. This means their skeletons are made of cartilage, not bone. Sharks and rays are also cartilaginous fish. Some types of rabbitfish still live in our oceans today!

E. kawai is unique among its relatives. It is the only Edaphodon species found in the Southern Hemisphere. Its remains were discovered near New Zealand. Most other ancient rabbitfish fossils have been found in the Northern Hemisphere.

These fish first appeared about 415 to 360 million years ago. But the only known E. kawai fossil dates to the Late Cretaceous period. This was a time when rabbitfish were very diverse. The name kawai means "fish" in the language of the Moriori people. They are a tribe from the Pacific islands.

What Was Edaphodon kawai Like?

Scientists usually learn about ancient cartilaginous fish from small pieces. For E. kawai, they found parts of its teeth and a beak. When E. kawai was officially described in 2006, it taught scientists new things.

One big discovery was its location. Before E. kawai, scientists thought all ancient Edaphodon species lived only in the Northern Hemisphere. But the fossil pieces of E. kawai were found in the Chatham Islands. These islands are close to New Zealand. This discovery showed that ancient rabbitfish lived in more places than thought. The E. kawai fossil was found in a rock layer called the Takatiki Grit. It dates back to the Late Cretaceous period.

Its Special Teeth

Another interesting fact about E. kawai was its unusual teeth. Most rabbitfish, unlike sharks and rays, have one set of teeth. These teeth don't grow back. They are used for grinding food, like a millstone. Rabbitfish also have mouths on the underside of their heads. This helps them graze on the seabed, like a land animal eating grass.

But E. kawai was different. Its teeth were made for both grinding and cutting! This meant it could eat a wider variety of food. It could even scavenge and tear meat from dead animals. Other rabbitfish could only crush soft organic matter. E. kawai lived when rabbitfish were at their most diverse.

Some scientists have wondered if the E. kawai remains might belong to another ancient fish. They suggest it could be Ischyodus. This fish lived around the same time. It has also been compared to the modern rabbitfish Chimaera monstrosa.