Fossil fish sheds new light on extra teeth evolution to devour prey

Experts discovered the first known example of fish with additional teeth deep in his mouth – a fossilized fish of 310 million years which has evolved a unique way of devouring prey.

Platysomus parvulus had a unique way of eating never seen in the fishing fish at the same time – a “tongue bite”, using a special set of teeth on the ground and the roof of the mouth to help it crush and chew difficult food like shells or insects.

Most fish today use their jaws to bite and chew, but some also have tongue stings, which work like a second set of jaws. Until now, the oldest known fish with such dental arrangement lived around 150 million years later.

Publish their results in Biology lettersThe international research team used high resolution computed tomography to rebuild the internal anatomy of the fossil, which was discovered in the carboniferous rock formations in the British County of Staffordshire. The researchers discovered a sophisticated arrangement of dental plates on the roof of the mouth of the fish and the branchial skeleton.

The main author, Professor Sam Giles, of the University of Birmingham, said: “Our discovery helps us to understand how fish have evolved after the extinction of final-reversal mass, which has destroyed many species. After this extinction event, fish began to change and develop new body forms and food ways.

“Language bites have evolved several times in different groups of fish, including in modern groups such as trout and fish-os, demonstrating that it is a useful tool that helps fish to eat a greater variety of food and survive in different environments.”

The mechanism of the bite of the tongue implies sets of opposite teeth – one on the roof of the mouth and another on the branchial skeleton – which work together to grasp and crush the prey.

The Plasysomus fossil studied is only preserved in 3D, allowing researchers to look in their mouths and digitally dissect its anatomy. This reveals a lower dental plaque in several parts and a narrow upper plate, both carrying a single layer of pointed teeth, which follows a transition stage in the evolution of more advanced language bite systems observed in subsequent fish like Bobasatrania.

The co-author, Dr. Matthew Kolmann, of the University of Louisville, said: “Later, the fish, like the Bobasatrania group, had more advanced language stings and did not use their jaws at all, counting on their tongue bite to crush hard food. Playsomus Parvulus is like a missing link between simple jaw fish and advanced. “

The discovery supports a rapid innovation model in the swimming fish of the first rays after the extinction of final-reversal mass, with the experimentation of spokesal swimming fish with new food strategies.

The co-author of Professor Matt Friedman, of the University of Michigan, said: “Language bites are only one of the many food innovations that emerged during this period. This fish represents a key evolving step and helps us understand how the ecosystems worked and how modern fish lines have become.”