The dinosaur "Nipponosaurus", which was first studied by the Japanese, will be in the spotlight again.A research group led by Ryuji Takasaki, a graduate student of Hokkaido University, conducted a re-research on Nipponosaurus.Unraveled the mysteries of growth stages and taxonomy.
Nipponosaurus Saharinensis is a herbivorous dinosaur that belongs to the Hadrosauridae family. It was discovered in 1934 in Sakhalin, which was a Japanese territory at that time, and was researched and named by Professor Takumi Nagao of Hokkaido Imperial University in 1936.This fossil, which was the origin of dinosaur research in Japan, is still known as the best-preserved whole skeleton owned by Japan.
A re-study was conducted in 2004, and it was identified as a fossil of a child.However, because the shape of dinosaur bones changes with growth, it has even been questioned in subsequent studies that it is an independent species.
This time, the research group observed the internal structure of the bone and confirmed that there are only two "growth stop lines" that are indicators of the age of dinosaurs.It was confirmed that he was a child before sexual maturity.In addition, after clarifying the changes in bones associated with the growth of hadrosaurids, we discovered the unique characteristics of Nipponosaurus that do not change during the growth stage.Proved the effectiveness of the species.
Furthermore, when reclassified in consideration of changes due to growth, it was found that Nipponosaurs are more primitive Hadrosaurus than previously thought.It has also become clear that it is closely related to European species.As a result, Nipponosaurus overturned the old hypothesis that it came from North America and established a new hypothesis that it traveled from Europe across the Eurasian continent to the Far East.
In the future, it is expected that the relationship with other dinosaurs in Japan and East Asia will be clarified.
