Jurassic Fish Crushed Shells With Its Pebble-Shaped Teeth

Posted on January 16, 2015

A Jurassic fish used its masses of pebble-shaped teeth to crush shells as it consumed creatures living on the ocean bottom. The fish, Dapedium, lived about 200 million years ago. The fish had jutting front teeth and many pebble-shaped teeth in the back of its tiny mouth.

University of Bristol undergraduate Fiann Smithwick conducted a study of the jaw mechanics of the ancient fish. Smithwick examined over 89 Dapedium specimens and measured the positions and length of the jaw bones in each specimen. He then used a lever-based mechanical model to reconstruct the feeding behavior of the shell-crushing Dapedium.

Professor Mike Benton, Fiann's supervisor, says in a statement, "Every time he ran the model, the result was the same. The outputs showed that Dapedium was a shell crusher. Its jaws moved slowly, but strongly, and so it could work on the hard shells of its prey. Other fishes have fast-moving, but weaker jaws, and those are adapted for feeding on speedy, slippery fish prey."

The researchers compare the Dapedium to the modern sea breams, which are flat-sided like the Dapedium and also use their small mouths armed with blunt-topped teeth to crush the shells of their prey.

Smithwick's research paper on the feeding ecology of Dapedium is published here in the journal Palaeontology.



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