THE discovery of a dinosaur “mummy”, complete with stomach contents, promises to be one of the most important dinosaur discoveries for years. The remains should reveal new details about the dinosaur’s diet, as well as its muscles, movement and development.
The dinosaur, a young plant-eating hadrosaur (Brachylophosaurus canadensis) that walked on two legs, was preserved under a layer of wet sand, says Mark Thompson of the Phillips County Museum in Malta, Montana. After the creature died, around 77 million years ago, anaerobic bacteria slowly replaced the animal’s tissues with carbonate rock leaving behind an accurate replica of the animal.
Most dinosaur findings amount to little more than scattered and often fragmentary bones. Fully articulated skeletons and imprints of skin and feathers are rare. Palaeontologists have only described three other mummies with the 3D structure of dinosaurs’ body tissue preserved and these were all excavated more than 70 years ago when techniques for extracting them from surrounding rock and preparing them for analysis were cruder than today. One of these mummies was lost in the Atlantic when the boat transporting it sank during the Second World War.
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Nate Murphy, also of the Phillips County Museum, discovered the latest mummy in Montana two years ago and last year hauled it back to the lab in a 6-tonne block of rock. Since then, Murphy and his team have been carefully removing the rock. It will be two more years before they’re finished.
So far, the palaeontologists have revealed the animal’s throat structure and shoulder muscles. The mummy also has preserved tendons, beak, foot pads and a frill that ran up its back. Inside the body cavity, the scientists found pulverised plant fragments that are “the most unequivocal stomach contents in the world”, according to Thompson.
The gut contents have not been mineralised, and the team identified pollen from 40 different plants in the dinosaur’s last meal. Scientists have been sceptical about previous claims to find food inside dinosaur skeletons, suspecting the plant matter drifted into the creature’s ribcage a long time after its death. But Thompson says this scenario is unlikely with their mummy. The skin of the dinosaur was intact when the body was preserved and no plant remains were found around it, he says.
Last week in Norman, Oklahoma, the team told a meeting of the Society of Vertebrate Paleontology about their find. “The exceptional preservation offers researchers new insights and a chance to test their theories about dinosaur biology,” says Murphy.