About 425 million years ago, an evolutionary innovation emerged among primitive fish that determined the later course of vertebrate development. Some jawless gill arches, which originally served to support the respiratory apparatus, slid forward into the first jaws.

At the same time, the first true teeth appeared, which ancient jawless fish did not have. There are several theories of their origin, including development from fish scales or horn formations of the pharynx, but eventually the teeth and jaws formed a single apparatus that served to grasp and hold large prey that actively resisted.

And now Chinese scientists have described the oldest fish with teeth – Qianodus duplicis. The fossils were discovered in Southern China, in Guizhou province in 2019, and they represent a type of tooth spiral over which several long, sharp teeth grow. These teeth are at least 14 million years older than other teeth discovered by paleontologists.

A new species of fish was a dangerous predator / eurekalert.org

Teeth played an important role

The emergence of teeth in vertebrates led to an explosion of biodiversity, and soon many animals capable of biting and tearing their prey were already swimming in the ancient seas. Ancient jawless animals quickly gave up their role in ecosystems, and at the start of the Devonian 419 million years ago, ancient cartilaginous and bony fish reached unprecedented diversity, this time dubbed the “Age of Fish.”