TOKYO (AP) - Japanese and Mongolian scientists have successfully recovered the complete skeleton of a 70-million-year-old young dinosaur, a nature museum announced Thursday.

The scientists uncovered a Tarbosaurus - related to the giant carnivorous Tyrannosaurus - from a chunk of sandstone they dug up in August, 2006 in the Gobi Desert in Mongolia, said Takuji Yokoyama, a spokesman for the Hayashibara Museum of Natural Sciences, a co-organizer of the joint research project.

"We were so lucky to have found remains that turned out to be a complete set of all the important parts," he said.

After two years of careful preparatory work, scientists found that the fossilized skeleton only lacked neck bones and the tip of the tail.

Young dinosaur skeletons are hard to find in good condition because they often are destroyed by weather decay or because they were torn apart by predators. The latest find would be a major step toward discovering the growth and development of dinosaurs, Yokoyama said.

The fossil, believed to have died at age 5, measured about 6.6 feet long, he said. Adult dinosaurs of the species are believed to have grown up to 40 feet.

The dinosaur, whose gender was unknown, came from a geological layer created about 70 million years ago in the late Cretaceous period.

The Japanese scientists and colleagues from the Center of Paleontology under the Mongolian Academy of Sciences have been jointly conducting dinosaur excavations in the Gobi Desert since 1993.

The Japanese museum is run by Hayashibara Co., a biotechnology firm based in Okayama, western Japan.