'Largest dinosaur foot to date discovered'

Scientists today said they have discovered the largest dinosaur foot ever - nearly a metre wide - belonging to a brachiosaur, which was among the biggest land animals on Earth.

The study, published in the journal PeerJ, is based on fossils excavated in Wyoming, US, and confirms that 150 million years ago brachiosaurs called a huge swath of North America home.

"This beast was clearly one of the biggest that ever walked in North America," said Emanuel Tschopp, a postdoctoral fellow at the American Museum of Natural History.

"There are tracks and other incomplete skeletons from Australia and Argentina that seem to be from even bigger animals, but those gigantic skeletons were found without the feet," Tschopp said.

The foot was excavated in 1998 by an expedition team from the University of Kansas, which included Anthony Maltese.

"It was immediately apparent that the foot, nearly a metre wide, was from an extremely large animal, so the specimen was nicknamed Bigfoot," said Maltese, lead author of the study.

After thorough preparation and examination, researchers have identified the foot as belonging to an animal very closely related to the long-necked, long-tailed sauropod Brachiosaurus, best known as the sauropod featured in the movie Jurassic Park.

The researchers used 3D scanning and detailed measurements to compare the specimen to feet from numerous dinosaur species. Their research confirms that this foot is the largest dinosaur foot discovered to date.

The study also shows that brachiosaurs inhabited a huge area from eastern Utah to northwestern Wyoming.

"This is surprising. Many other sauropod dinosaurs seem to have inhabited smaller areas during that time," Tschopp said.

The rock outcrops that produced this fossil - the Black Hills region of Wyoming, famous today for tourist attractions like Deadwood and Mount Rushmore - hold many more fantastic dinosaur skeletons, said Maltese.