The world was teeming with huge creatures

The newly-discovered fish lizard is not by far the only species with huge members. Prehistoric sharks weighed 60 t, and the biggest modern squid of 450 kg was not afraid of attacking sperm whales.

The prehistoric giant’s eyes measured up to 22 cm, and simulations of the fish lizard’s vision show that the predator had a fabulous eyesight that could spot prey at depths of down to 1,600 m. The marine animal’s oblong body shape and large fins even reveal that the fish lizards were fast hunters that could accelerate quickly through the water to hunt their prey.

The largest fish lizards were not what biologists have named top consumers – i.e. a predator at the top of the food chain that consumes other large animals. Like many modern whales, they probably fed themselves by swimming through large shoals of crustaceans and fry with their mouths open. Like the blue whale, the biggest prehistoric fish lizards produced overpressure in the water, as they opened their mouths, so the prey was sucked into the mouth.

Lizard beats blue whale

Exactly how the new fish lizard secured food is not disclosed by the find of the new jawbone, but Paul de la Salle’s fossil has still taught scientists a lot. First, the three palaeontologists who received the fossils from Paul de la Salle had to prove that the bone was actually from a fish lizard. They did so by studying the fossil’s anatomy in detail – such as a deep groove in the jawbone, through which nerves and cartilaginous tissue originally ran. Subsequently, the scientists compared the new find with particularly well-preserved skulls of other fish lizards such as the about 7-m-long Platypterygius from Australia, which palaeontologists used to study by means of very detailed X-rays. When the scientists had confirmed that they had a bone fragmenst of a brand new member of the family of fish lizards, they visited the Royal Tyrrell Museum of Palaeontology in Alberta, Canada, which includes one of the biggest fish lizard species scientists have ever known – a 21-m-long giant by the name of Shonisaurus. By comparing the new bone discoveries with the exhibited jawbone belonging to the Shonisaurus, the three scientists discovered that the new bone was 25 % bigger. This means that the new fish lizard species probably measured some 26 m. In comparison, an average adult blue whale is approximately 25 m long. The biggest surprise presented itself, when the new bone was compared to three large