The dispute about dinosaurs has never existed

67 million years ago, a dinosaur died and turned into fossils, causing a controversy over recent years.

In 2003, the Burpee Natural History Museum in Illinois unearthed this fossil. The 6m long, 2m high fossil remains intact. There are sharp teeth and long limbs, surely this is a carnivorous dinosaur. Although it is unclear, it is still called "Jane" , belonging to the genus Nanotyrannus (baby meat dinosaur).

Restoring Jane.

This is not the only case. Previously, David Dunkle from the Cleveland Museum in Ohio also unearthed a skull of Jane's dinosaur, known as CMNH 7541 . However, after a poor study, expert Charles W. Gilmore placed it in the same category as Gorgosaurus, also a relative of T.rex living in the early Cretaceous period.

In 1970, CMNH 7541 was re-classified into the Albertosaurus group. In 1988, Bob Bakker and colleagues at the University of Colorado reviewed it, thinking that CMNH 7541 belonged to the Nanotyrannus genus above. But not yet. In 1999, researcher Thomas Carr discovered that T.rex's teeth and skull could grow over time, not fixed size.

Accordingly, adults have bones, large and dense, heavy teeth, while the offspring are growing smaller with modest teeth. In other words, the Nanotyrannus dinosaurs didn't exist, and Jane was just a baby T.rex.

Skull CMNH 7541.

In fact, this is not new. Scientist Anatoly Rozhdestvensky from the former Soviet Union confirmed that CMNH 7541 was only T.rex since 1965, but has been largely ignored. Thus, fossils may be mistaken as a new species.

"Imagine imagining the remains of children. If you don't understand how humanity evolves, then the misconception is the same kind of humanity as possible," Stephen Brusatte from Edinburgh University (England). ) comment.

Later analysis shows that the fossil itself also shows the same thing. Like age rings in woody stalks, dinosaur bones can show their exact age. Aged adults in the bones are close to each other due to less bone development, and vice versa for young animals. Based on that foundation, the results show that Jane died when she was 12 years old. Most T.rex reach adulthood at the age of 20 and age and die when they are over 30 years old.

Compare sizes of T. rex and people.

In theory, Jane could still be a Tyrannosaurus strain with a short lifespan , but analyzing bone fragments indicates that the age rings are quite far apart, indicating Jane is still in growth. The results of the study of the bones of two smaller strains, Gorgosaurus and Albertosaurus, also support this argument, because T.rex has a different development process for its size. Other limbs increase by about 500grams per day, particularly T.rex is 2kg.

Thus, Jane can bring a new look to this dinosaur breed. If not die soon, it will soon reach the standard size several times."The development of T.rex is like an evolutionary one. It must grow at a record rate to reach 7 tons and 13m in length. This is something we must continue to explore , " Brusatte said.