A team of scientists has discovered exceptionally preserved fossils of a "dog-sized" dinosaur that lived underground in Utah, more than 99 million years ago.
The new species, called Fona Herzogae, was a small, plant-eating creature with powerful muscles, a compact pelvis for stability, and large hind legs ideal for its underground lifestyle.
Scientists have found nearly complete skeletons of several creatures still in their original death position, chest down and forelimbs flattened, indicating they died beneath the surface of the land.
The research team at North Carolina State University and the North Carolina Museum of Natural Sciences said they were surprised by the number of dinosaur fossils they had found in the area since 2013, most of which were still in their original death position.
The study explained that the discovery area was covered in a warm, humid, muddy environment. These environmental conditions usually cause fossils to deteriorate or scatter over time, but the remains discovered were so well preserved that the research team believes the creatures may have spent time underground.
“The best explanation for why so many of them were found and recovered in small groups is that they lived at least part of the time underground,” said study co-author Dr. Lindsay Zanno.
Scientists have yet to find the caves that Fona might have dug, but they say they have found tunnels in Idaho and Montana created by a creature called Oryctodromeus, strengthening their belief that the dog-like dinosaur also hid underground.
This discovery is new and amazing, because previous scientific discoveries only indicated that dinosaurs were aquatic, terrestrial, or flying in the air.
These fossils may give us a better idea of the different types of dinosaurs, their ability to adapt to certain environmental conditions, or how they escaped from predators.
The study was published in the Journal of the American Society of Anatomy.