What it is
An ichthyosaur, a reptile that lived in the sea and came up to breathe. Picture a dolphin, built at the size of a whale. Its name means the giant fish lizard. It lived about 202 million years ago, at the very end of the Triassic.
How big
It is known from pieces of jawbone found on the coast of Somerset, in England. One bone, from the back of the lower jaw, was more than two meters long. Scaled up from a smaller relative that left a whole skeleton, the animal comes to about 25 meters. That is about as long as a blue whale. It would be the biggest marine reptile ever found. But it is an estimate, from two bones, and the scientists say so themselves. Nobody has found the rest.
Still growing
Under a microscope, the bone was still being built. This animal had not finished growing. Scavengers had scraped at the jaw on the seafloor, and shells grew on it.
The last giants
In the rock just above the layer with the jaw, the seabed is shaken and torn. It is the mark of a mass extinction. Ichthyosaurs lived on for another hundred million years, but they never grew this big again.