LONDON - A new dinosaur named "Thunder Thighs" has been identified by British and US scientists who said its huge, muscular legs would have given it a fierce kick.

Researchers retrieved bones from two incomplete skeletons - an adult and a juvenile - from a previously looted quarry in Utah in the western United States.

Scientists found that the Brontomerus - Latin for thunder thighs - had a uniquely shaped hip bone, which was unusually large when compared to similar long-necked sauropod dinosaurs like the Diplodocus and Brachiosaurus.

The bone provided a proportionally massive area for the attachment of muscles, leading researchers to say its thighs were like a "dinosaur four-wheel drive".

The dinosaur, Brontomerus mcintoshi, was also named after US paleontologist John "Jack" McIntosh.

"Brontomerus mcintoshi is a charismatic dinosaur and an exciting discovery," said Mike Taylor, a researcher in the Department of Earth Sciences at University College London.

"When we recognised the weird shape of the hip, we wondered what its significance might be, but we concluded that kicking was the most likely.

"The kick would probably have been used when two males fought over a female, but given that the mechanics were all in place it would be bizarre if it wasn’t also used in predator defence."

Paleontologists believe the larger specimen was the mother of the younger and would have weighed around six tons - about the size of a large elephant - and measured 14 metres in length.

The smaller specimen would have weighed about 200 kilogrammes - the size of a pony - and measured 4.5 metres long.

The authors classified the new genus based on bones from the shoulder, hip, ribs, vertebrae and some unidentifiable fragments.

The shape of the hip bone indicates that the animal would likely have had the largest leg muscles of any dinosaur in the sauropod family.

Doctor Matt Wedel, assistant professor of anatomy at the Western University of Health Sciences in Pomona, California, said: "It’s possible that Brontomerus mcintoshi was more athletic than most other sauropods.

"It is well established that far from being swamp-bound hippo-like animals, sauropods preferred drier, upland areas.

"So perhaps Brontomerus lived in rough, hilly terrain and the powerful leg muscles were a sort of dinosaur four-wheel drive."

Brontomerus lived about 110 million years ago, during the Early Cretaceous Period.

The new species is described in a paper published in the journal Acta Palaeontologica Polonica.