Apr 27, 2007
For months, Japanese schoolchildren at a Katsuyama educational facility pretended to be paleontologists with what has turned out to be a very valuable rock.
The rock contains a rare dinosaur skin impression, according to an announcement made last week by officials at the Fukui Prefectural Dinosaur Museum.
"What is important about this skin impression is that it (represents) the first such discovery for Japan," Masateru Shibata told Discovery News.
Shibata is a researcher and paleontologist at the museum.
Scientists originally excavated the rock containing the impression from a site called the Kitadani Quarry in Katsuyama. Its particular layer was dated to the Early Cretaceous period, around 120 million years ago.
Within the rock, researchers noticed the impression on a 9-inch-square, 2.7-inch-thick plate of fine-grained sandstone. Researchers believe the dinosaur that left its mark there probably collapsed and died on a wet surface. Sand covered the carcass before it fossilized.
The skin impression covers about 60 percent of the plate's surface. It shows both polygonal and circular scales, each measuring a fraction of an inch.
Judging by the scale pattern and the shape of the imprint, scientists speculate the skin came from the leg of a plant-eating dinosaur. It may have been a hadrosaur, an amphibious dino with webbed feet and a duck-like bill.
Researchers in Japan think it could be from Fukuisaurus, a 15.5-foot-long hadrosaur belonging to the subgroup iguanodontia. This subgroup includes some of the world's largest known veggie dinosaurs, some of which measured up to 50 feet long and weighed as much as 8 tons.
While not quite as hefty, the still-large Fukuisaurus once roamed Japan. A full skeleton of this dinosaur was excavated near the location where the skin fossil was found.
Shibata, however, admitted that a precise identification may never be possible since the impression was not directly linked to the bone finds.
Mark Goodwin, assistant director of the University of California Museum of Paleontology, said the discovery is indeed "a first for dinosaur-bearing sediments in Japan."
"The scale pattern may shed some light on what dinosaur it came from if comparisons can be made with dinosaur skeletons, such as hadrosaurs, from North America that have skin or skin impressions preserved over the bones," Goodwin told Discovery News.
These are often referred to as "mummified dinosaurs," he added.
The dinosaur skin impression will be on display at the Fukui Prefectural Dinosaur Museum in Katsuyama through May.