Fossil of dinosaur-skin traces found

Workers at a leisure facility found a fossil containing traces of dinosaur skin patterns, a rare discovery that could shed light on the actual appearance of the creature, the Fukui Prefectural Dinosaur Museum said Thursday. Museum officials said classifying the dinosaur has been difficult because fossils of its bones have not been found. But they said it could be a plant-eater from the early Cretaceous Period, about 100 million to 140 million years ago, judging from the age of the stratum where the fossil was found. Illustrations and reproductions of dinosaurs are largely based on guesswork, given the scarcity of fossilized skin in comparison to bones and teeth. "It is extremely rare for skin to be preserved as fossil because unlike bones, skin rots," Yoichi Azuma, assistant director of the museum, said. "We'd like to continue research on the fossil and use the results for restoring dinosaurs in detail and other purposes." The latest finding will be displayed at the museum from today through the end of May. Museum officials said the skin traces might have been left on the surface of the wet ground when the dinosaur tumbled or collapsed. The traces are believed to have been covered by sand and were fossilized over the eons.

In 1995, traces of skin were discovered from a fossil of a dinosaur's footprint at a nearby location. The latest traces were found on the surface of a 23- to 24-centimeter square, 7-cm-thick plate of fine-grained sandstone in the Katsuyama's Kitadani-cho district. The traces covered about 60 percent of the plate's surface, with polygonal and circular patterns of 3-5 millimeters in diameter and up to 1 mm in height. The plate was among rocks taken from the Kitadani stratum, the upper part of the early Cretaceous Period layers collectively known as the Tetori group. These layers are estimated to have formed about 120 million years ago. The rocks had been brought to a leisure facility, where children can excavate fossils. The plate was discovered in October by workers at the facility.