Introduction Kamuysausus japonicus. an entirely new genus and species of adverb from Japan. The location of its fossilized remains suggests that these majestic herbivores circled ancient shorelines, extending our knowledge of this wildly successful dinosaur group.
New research published today in Scientific Reports describes Kamuysaurus japonicus a species of adrosaur or a dinosaur with a duck taken from the Japanese Hakobuchi Formation. The nearly complete fossil skeleton was discovered in offshore fields at 72 million years, suggesting that the creature has been feeding along the coastline, which is rare for hadrosaurs.
"This is a beautiful new dinosaur skeleton and probably one of the most important dinosaurs ever found in Japan."
The bones of Kamuysaurus japonicus have been discovered along with the fossilized remains of sea turtles and mosaics (an extinct water reptile that looked a lot like a modern whale), further reinforcing that this dinosaur lives by the sea.
"This is a beautiful new dinosaur skeleton and probably one of the most important dinosaurs ever found in Japan," Steve Brusate, a paleontologist at the University of Edinburgh who did not participate in the study, told Gizmodo in an email.
Hadrosaurus is a super successful group of dinosaurs that lived during the Late Cretaceous (100 million to 66 million years ago), with their fossilized bones restored in Eurasia, North and South America, and Antarctica. These herbivores can walk on four or two feet, allowing them to graze on the ground or reach tall branches.
As early as 2013, the partial tail of this specimen was discovered during the Hakobuchi Formation, leading to more extensive excavations at the site. The scientists were able to find a nearly complete skeleton, the bones of which were carefully analyzed by paleontologist at the Hokkaido Museum of Hokkaido University, Yoshitsugu Kobayashi and his team. It is "the largest dinosaur skeleton ever discovered in Japan," according to a press release from Hokkaido University.
Paleontologist Liz Friedman Fowler, associate professor of biology at Dickinson State University, says dinosaur fossils from Japan are "rare and usually very fragmentary, so it's very exciting to have such a remarkably full skeleton." Unrelated to the new study, Friedman Fowler described the new study as "multifaceted and very well done."
The physical analysis of the specimen includes about 350 individual bones. The creature was a medium sized, fully grown hadrosaur, who was about 9 years old when he died. Researchers speculate that his corpse floated out to sea, eventually falling on the seabed, allowing it to remain in a sediment. When alive, this herbaceous tree was about 8 meters long and weighed up to 5.3 tons.
In the new study, Kobayashi and his colleagues say Kamuysaurus japonicus was similar to the Chinese Laiyangosaurus to Russia, and that he belongs to the clan of the Edmontosaurini dimosaurs. Accordingly, research provides a new idea of the origin of this treasure and how these animals are spread throughout the planet. Kamuysaurus japonicus and his close relatives probably travel through Alaska, which connects Asia to North America through the Late Cretaceous.
"She is a member of a group that appears to have immigrated from North America and subsequently diversified. in Asia at the very end of the dinosaur era, ”Brusat explained. "Another reminder that dinosaurs actively moved around and diversified until the end of their reign."
This type of hadrosaurus has three unique physical characteristics that set it apart from other members of the Edmontosaurian clan, thus guaranteeing the creation of of a whole new genus and species of dinosaurs. These features included a small ridge on his skull, a short row of forwards forward spines on his back, and shorter than the normal bone plate in his jawbone.
As hadrosa crests "grow and change shape as the animal grows," they can be used to determine if the specimen is an adult, Friedman Fowler said.
"This skeleton is close to full size for that kind, and the bones of the skull show that there was a bone with a large size of ridge on the skull, which was unexpected for a relative of Edmontosaurus who had a soft-tissue comb of his otherwise dull skull, "Fowler explained in an email to Gizmodo. "The bone of the nasal crest itself is missing, so the next puzzle will be to find out exactly what shape this crest would be."
As a last note, we asked Friedman Fowler if it was still correct to refer to hadrosaurs as "duck-billed dinosaurs." "
'Good question,' she said. 'We know this is a bad term and not accurate, but we have nothing better to do to the general public – we still say' dinosaurs with a duck '."