Co-authors with Cifelli of the paper detailing the discovery are Mike Taylor, a researcher in the Department of Earth Sciences at University College London, and Matthew Wedel, assistant professor of anatomy at Western University of Health Sciences, Pomona, Calif.
The paper is published in the British journal Acta Palaeontologica Polonica.
Taylor said the bones discovered by the Sam Noble researchers were used to identify the dinosaur's unique features, primarily the shape of the hip bone.
The wide, blade-shaped bone projects forward ahead of the hip socket, providing a proportionally massive area for the attachment of muscles.
“When we recognized the weird shape of the hip, we wondered what its significance might be, but we concluded that kicking was the most likely,” Taylor said.
Wedel, who first studied the bones as a graduate student at OU, said other marks give additional clues to its lifestyle and environment.
The Brontomerus probably had powerful forelimb muscles and may have been more athletic than other sauropods, he said.
The powerful leg muscles “were perhaps sort of a dinosaur four-wheel drive,” Wedel said.
Brontomerus' unusual hip structure and enormous thigh muscles place it on the list of most extreme dinosaurs, Cifelli said.
Cifelli said the discovery also is significant because it is one of a number of finds over the past 20 years that challenge the previously held idea that sauropods began to disappear in the early Cretaceous period.