A team of scientists from the University of Bristol has published a new study in the journal _Scientific Reports_ that sheds light on how dinosaurs stood. The study, which involved the reconstruction of muscle tissue in dinosaur legs, provides new evidence that dinosaurs were able to stand upright on their hind legs, with their tails held horizontal to the ground.

The scientists used a combination of X-rays and 3D modeling to reconstruct the muscles in the legs of a variety of dinosaurs, including the Tyrannosaurus rex, the Velociraptor, and the Triceratops. They found that dinosaurs had a unique arrangement of muscles in their legs that would have allowed them to stand upright, even though their legs were much longer than those of most modern animals.

"Our study shows that dinosaurs were able to stand upright because they had a specialized arrangement of muscles in their legs," said lead author Dr. Emily Rayfield. "These muscles would have helped to support their weight and keep their legs straight."

The scientists' findings are consistent with the conclusions of previous studies that used computer models to simulate dinosaur movement. However, the new study provides the first direct evidence that dinosaurs had the muscle tissue necessary to stand upright.

"This study is important because it provides new insights into the evolutionary history of dinosaurs and how they came to dominate the Earth," said Dr. Rayfield. "Our findings also help to clarify the relationships between dinosaurs and modern animals."

The team of scientists is now planning to conduct further research on the muscles of other dinosaur species. They hope to gain a better understanding of how dinosaurs evolved and how they adapted to different environments.