Rock Found 52 Years Ago in Japan Confirmed as Dinosaur Egg Fossil

Fukui, June 5 (Jiji Press)--A rock collected in 1965 by a then high school student in the city of Shimonoseki, Yamaguchi Prefecture, part of the Chugoku region of western Japan, has been confirmed to be a dinosaur egg fossil, the city and the Fukui Prefectural Dinosaur Museum said Monday. Previously, fossils of eight types of dinosaur eggs have been discovered in Japan, in the prefectures of Fukui, Gifu and Hyogo. The fossilized egg confirmed this time is different from the eight types, and it is highly likely to be an egg laid by a bipedal carnivorous dinosaur, or theropod, the city and the museum said. The egg fossil, broken into pieces, is also the dinosaur fossil found earliest in the country. Previously, a fossil of the upper arm of a Moshiryu dinosaur found in the town of Iwaizumi, Iwate Prefecture, northeastern Japan, in 1978, had been considered to be the first dinosaur fossil discovery in the nation. The rock was collected by Yoshiharu Shimizu, a native of Shimonoseki, and a friend in September 1965, when Shimizu was a second-year high school student, according to the museum in the city of Katsuyama, Fukui Prefecture, central Japan. They discovered it in a layer dating back to the early Cretaceous period, or between some 120 million and 100 million years ago, in the upstream area of the Ayaragi river in Shimonoseki. Shimizu, now a 68-year-old company employee in the city of Yokosuka, Kanagawa Prefecture, eastern Japan, has kept the rock pieces at his house, along with sketches and photos of the item as well as the photo negatives. After recalling the treasure trove, he asked a nephew, who is an employee of the municipal government of the city of Mine, Yamaguchi, in March last year to find out what they are. The Fukui museum worked with entities including the Mine Fossil Museum to identify them. The eight pieces are 2 to 7 centimeters in diameter. After taking photos of the rock he collected, Shimizu broke it into pieces with a hammer. His sketches and other information suggest that the egg was either spherical or oval in shape, with an estimated diameter of some 10 centimeters. The egg shell is some 3.7 millimeters thick, far exceeding some 0.1 to 0.7 millimeter of other dinosaur eggs found in Japan. "Direct evidence that dinosaurs existed in the Chugoku region had not been discovered before," said Takuya Imai, 29, researcher of the Fukui museum who examined the rock fragments. "The discovery of the egg fossil shows that dinosaurs bred actively in the region in the early Cretaceous period," he said. Yoichi Azuma, 67, executive director of the museum, said, "The discovery rewrote the history of dinosaur research," noting that the sketches by Shimizu were very accurate. The site where the rock was collected and the date of collection that are important in verifying the authenticity of the discovery were on the sketches. Had it not been for the data, it would have been impossible to make an objective judgment that the egg represents the first dinosaur fossil discovery in Japan, according to Imai. Noting that taking photos and drawing sketches are part of research, Azuma stressed that the latest development "could mark the start of dinosaur research in Japan." In a statement released Monday, Shimizu said: "My high school teacher taught me the importance of taking records. I believe this helped lead to the result." In Shimonoseki, Shintaro Maeda, mayor of the city, said, "We want to share the joy with citizens, and send the news to dinosaur fans across Japan and throughout the world." Maeda also underscored his city's willingness to promote tourism by taking advantage of the news. END