Fossilised 'ocean lizard' found inside 'sea monster' reveals rare behaviour
Reconstruction of the Shonisaurus, a giant ichthyosaur. Nobumichi Tamura
Massive sea monsters capable of eating prey almost its own size hunted in pre-historic oceans much earlier than believed, scientist have said.
The claim has been bolstered by the discovery of a 240-million-year-old fossil from the Triassic time.
In a time before dinosaurs, a dolphin-like reptile known as an ichthyosaur swallowed an ancient lizard-like ocean reptile called a thalattosaur, then died with the undigested remains still in its stomach.
READ MORE: The earth was once home to 'terror crocodiles'
This image shows the ichthyosaur specimen with its stomach contents visible as a block that extrudes from the body. Ryosuke Motani
This image shows the ichthyosaur's teeth. Jiang et al.
The predator measured five metres. It's near-intact prey was four-metres.
The fossilised remains of both beasts were discovered in southwestern China in 2010, however a study published in the journal iScience this week said the unique fossil disproves the assumption aquatic animals at the time didn't go after large prey.
The authors wrote that the fossil represents the oldest "evidence for predation on megafauna ie, animals equal to or larger than humans".
This graphic shows the fossil and compares the size of the two marine reptiles. Supplied
Until now only five other Mesozoic reptiles were found with the remains of other tetrapods in their stomachs, but in those instances only fragments of bones were found.
Much like the dolphins of today, ichthyosaurs breathed air and gave birth to live young.
However, they were known to approach sizes similar to a blue whale and were thought to eat squid-like cephalopods.
Reconstruction of the Shonisaurus, a giant ichthyosaur. Nobumichi Tamura
"The predator has grasping teeth yet swallowed the body trunk of the prey in one to several pieces," researchers said.
The researchers go on to state that such predation was probably common due to the presence of other animals with similar teeth.
"There were many more Mesozoic marine reptiles with similar grasping teeth, so megafaunal predation was likely more widespread than presently conceived."
The 'trunk', or middle, of the thalattosaur was found inside the ichthyosaur. Supplied
For breaking news alerts and livestreams straight to your smartphone sign up to the 9News app and set notifications to on at the App Store or Google Play.
You can also get up-to-date information from the Federal Government's Coronavirus Australia app, available on the App Store, Google Play and the Government's WhatsApp channel.
Share a tip-off, video or photo with us
