Giant reptile found ‘well-preserved in belly of larger carnivore’

Scientists say the fossil could be the first evidence of megapredation.

An ancient four-metre-long reptile has been found well-preserved in the stomach of a slightly larger marine carnivore that lived around 240 million years ago.

Scientists say the fossil, which was discovered in southwestern China, could be the first evidence of megapredation – a large animal preying on another large animal.

In a case of biting off more than it could chew, the five-metre-long ichthyosaur is thought to have died almost immediately after consuming its prey, possibly fatally injuring itself while trying to eat an enormous meal.

The findings have been described in the journal iScience.

The quarry where the ichthyosaur was uncovered, now part of the Xingyi Geopark Museum — The quarry in the Guizhou province, China, where the ichthyosaur was uncovered, which is now part of a museum (Ryosuke Motani/University of California)

While the shape of their blunt teeth suggests these animals may have been at the top of their food chain, there is little direct evidence of the kind of prey they consumed.

The specimen was first discovered in the Guizhou province in 2010 but it took scientists a decade to excavate the ichthyosaur fossil and notice the “large bulge” in its abdomen.

The ichthyosaur's teeth, with the broken white line indicating the approximate gum line of the upper jaw — The ichthyosaur’s teeth, with the broken white line indicating the approximate gum line of the upper jaw (Jiang et al/iScience)

The prey in question, a thalattosaur – a lizard-shaped reptile almost as long as the ichthyosaur but much skinnier.

The thalattosaur remains show little evidence of being broken down by digestive juices, which according to the scientists, suggests the ichthyosaur died shortly after consuming its final meal.

The stomach of the ichthyosaur contains the mid-section of another marine reptile that in life would have been only slight smaller (Jiang et al/ iScience)

The team also found the ichthyosaur’s body and head were detached from one another, indicating it may have died of a broken neck.

Dr Motani said: “We now have a really solid articulated fossil in the stomach of a marine reptile for the first time.

“Before, we guessed that they must have eaten these big things, but now, we can say for sure that they did eat large animals.

“This also suggests that megapredation was probably more common than we previously thought.”