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More than 100 million years ago, a fearsome bird-like dinosaur was swept into a lake and transformed into an exceptional fossil in what is now China, preserving one of the few known intact intestinal remains. of non-avian dinosaurs, according to a new study.
Paleontologists knew they had unearthed something special when they saw ‘a large bluish layer in the abdomen’ of the fossilized beast, which belongs to the newly discovered species Fragrant daurlong, as well as a lineage of dinosaurs called the dromaeosaurids, which includes the ancestors of modern birds. This bluish layer had “exceptional preservation” of the dinosaur’s gut, the researchers wrote in the study, published in the journal Scientific reports (opens in a new tab) in Nov 19.
Discovery offers valuable insight into the gut of birds and dinosaurs evolutiongiving researchers a clearer window into dinnertime during the Lower Cretaceous (145 to 100.5 million years ago).
Related: These 125 Million Year Old Fossils Could Contain Dinosaur DNA
Dromaeosaurids — also known as “raptors” — love D. fragrant were mostly small, feathered and carnivorous. This group traveled the Earth from the mid-Jurassic (about 167 million years ago) to the end of the Cretaceous period (66 million years ago). Their ranks included some of the most famous pop culture dinosaurssuch as Velociraptor and Deinonychus. But despite their popularity, little is known about their true guts.
Soft tissue preservation is rare for any fossil, and gut preservation is especially rare in dinosaurs. “This is the first case among dromaeosaurids,” study co-author Andrea Cau, an independent paleontologist based in Parma, Italy, told Live Science in an email.
Fossilization conditions must be perfect in order to avoid decomposition bacteria chew through delicate soft tissue, such as cartilage and organs. The newly described D. fragrant specimen was probably buried very quickly under fine, soft sediment at the bottom of a body of water in what is now Jehol Biota – an area known for well-preserved fossils in modern Inner Mongolia, a northern autonomous region from China. There, in the low oxygen environment where aerobic bacteria could not survive, the dinosaur remains mineralized into fossils.
The researchers named the genus of the dinosaur, “Daurlong“, after the Daur people of Inner Mongolia and “long”, the Chinese word for “dragon”. The species name, “fragrant“, honors Wang Junyou, the director of the Natural History Museum of Inner Mongolia.
The remarkable preservation provides insight into how D. fragrant lived, and what he could have eaten. From what researchers could tell, its intestinal tract appears similar to the very few other known remains of carnivorous dinosaurs, suggesting that the gut plans of more omnivorous dromaeosaurids did not evolve until after the dawn of modern birds. after the Cretaceous period. It also appears that D. fragrant ate small prey, such as mammals (which were no larger than badgers in Mesozoic times), fish, other small dinosaurs, and possibly amphibians. “Given the abundance of frogs and other amphibians in the Daurlong locality,” it is possible that this dromaeosaurid hunted frogs and salamanders, Cau said.
Although D. fragrantThe entrails of were preserved, his stomach was not. Perhaps the animal’s “extremely acidic environment in the stomach immediately after death” prevented it from mineralizing and turning into a fossil, the researchers wrote in the study.
Unlike their depiction in the 1993 film “Jurassic Park”, most dromaeosaurids were relatively small and light. D. fragrant itself was just under five feet (1.5 meters) long from tip to tail, about the size of a pony. And, like the other members of his family, he sported feathers.
In the future, Cau and his team plan to examine the specimen more closely to better understand its feathers, its life and possibly its death. “Our hope is to determine some information about the color of its plumage in life and to better reconstruct the particular conditions that led to soft tissue preservation,” he said.
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