Jawbone fossil found in Somerset belongs to giant sea monster

A jawbone fossil found on a Somerset beach belongs to one of the biggest marine animals that ever lived, scientists say.

The reptile is from the ichthyosaur family, and is estimated to have been up to 26 metres (85 feet) long - almost the size of a blue whale.

The ichthyosaur lived up to 205 million years ago at the end of the Triassic Period and dominated the oceans just as dinosaurs were becoming the masters of the land.

Its bone, called a surangular, formed part of its lower jaw and was discovered in 2016 at Lilstock on the Somerset coast.

Researchers estimated the animal's length by comparing the surangular with the same bone in the largest ichthyosaur skeleton ever found - a species called Shonisaurus sikanniensis from British Columbia that was 21 meters (69 feet) long.

Paleontologist Dean Lomax, of the University of Manchester, said: "This bone belonged to a giant.

"The entire carcass was probably very similar to a whale fall in which a dead whale drops to the bottom of the sea floor, where an entire ecosystem of animals feed on the carcass for a very long time.

"After that, bones become separated, and we suspect that's what happened to our isolated bone."

Fossil collector Paul de la Salle, who found the bone, said: "The structure was in the form of growth rings, like that of a tree, and I'd seen something similar before in the jaws of late Jurassic ichthyosaurs."

On discovering the bone, he said: "Initially, the bone just looked like a piece of rock, but after recognising the groove and bone structure, I thought it might be part of a jaw from the ichthyosaur and immediately contacted ichthyosaur experts."

He later returned to the site and found even more pieces that together measured about a metre in length.

Scientists say ichthyosaurs prowled the world's oceans between 90-250 million years ago looking for squid and fish.

The biggest were larger than other massive marine reptiles of the dinosaur age and only today's filter-feeding baleen whales are bigger.