Dueling dinosaur bones could set fossil auction record NEW YORK (Reuters) - Fossils of two dinosaurs found in Montana and locked eternally in a fierce death match could fetch a potential record $9 million when they are sold in New York next week, the Bonhams auction house said on Thursday. The Montana Dueling Dinosaurs & Distinguished Fossils sale on Tuesday will feature 70 lots, including the two dinosaurs thought to have killed each other in fierce combat and then quickly been buried on top of each other. The most expensive dinosaur fossil sold at auction is a Tyrannosaurus Rex skeleton named Sue, which fetched $8.3 million in 1997. The sale, which Bonhams said could bring in $15 million overall, also includes a partial skeleton of a Tyrannosaurus Rex mounted in an attack pose and a 17-foot-long (5 meter) sea predator. It is uncommon to form a collection like this. It's a once in a lifetime discovery," Thomas Lindgren, Bonhams co-consulting director of natural history, said in an interview at a preview of the sale. The dueling dinosaurs fossil, which was discovered in 2006, contains two of the most well-preserved dinosaur remains ever unearthed, Lindgren said. It includes pieces of skin. One of the skeletons belongs to a ceratopsian, which is similar to a triceratops, but there is debate about its opponent. Scientists are unsure if the second animal is a juvenile Tyrannosaurus Rex or a new species. The remains could help settle the question. This is science that's been preserved. It is the most important dinosaur fossil sale of all time," Lindgren said, adding several American museums and an international institution have expressed interest in it. The last major dinosaur fossil sold by Bonhams was a Tyrannosaurus Rex fossil, named Samson, which brought in less than $5 million in 2009. The other mounted, standing fossils in the sale have less scientific value and would be more interesting to individual collectors or as show pieces for museums, Lindgren said. Next week's auction comes a year after the sale of a mammoth Tyrannosaurus bataar, a close relative of the T-Rex, which sold for more than $1 million. U.S. authorities returned the fossil to Mongolia after it was discovered the remains had been illegally poached from the Gobi Desert. Lindgren said the fossils in the current sale were discovered in the United States and are the property of the landowners, according to the Bureau of Land Management. Reporting By Curtis Skinner; Editing by Bill Trott