(Image: CK Preparations. Courtesy of Bonhams)

The two dinosaurs are locked in mortal combat, their fossilised bones forever twisted in a fatal struggle. And for a mere $7 million, their tangled remains could be yours.

The duelling dinosaurs are a Nanotyrannus lancensis and a Chasmosaurine ceratopsian. The Nanotyrannus, a predator similar to the ferocious Tyrannosaurus rex (some palaeontologists argue that Nanotyrannus is really a juvenile T. rex rather than a species in its own right) curls around the right of the image while its prey, the herbivorous Chasmosaurine, lies prone on the left. The latter's elongated skull reveals its similarity to the iconic Triceratops.

These well-matched foes would each have stood around 2.5 metres high and grown up to 10.5 metres long. During their violent struggle they inflicted fatal wounds on each other. Teeth from the Nanotyrannus were found embedded in the skull of the Chasmosaurine, and the Chasmosaurine gave as good as it got: the skull and chest of the Nanotyrannus seem to have been crushed, perhaps by a powerful kick from its intended meal.

(Image: Courtesy of Bonhams)

The fossil will be sold at auction by Bonhams in November. "They are one of the most significant dinosaur discoveries ever in North America," says Thomas Lindgren of the natural history department at Bonhams.

The dinosaurs' brutal fight to the death was uncovered in the appropriately named Hell Creek, Montana, in 2006. The Nanotyrannus fossil is only the second ever found and is by far the most complete.

The remarkably preserved fossils, a resin model of which appears in the photo, are expected to sell for between $7 million and $9 million – a bargain for a piece of decor guaranteed to strike fear into your enemies.