Found in Japan!

A new kind of "strange" dinosaur June 2, 15:31

In May 2022, research groups such as Hokkaido University announced that the fossils found in Japan more than 20 years ago belonged to a new species of dinosaur.

Japan was once thought to be a "dinosaur blank area" where fossils of dinosaurs did not appear.

In fact, it's one of the best dinosaur fossil hotspots in the world.

From the fossils announced this time, we will find out what kind of dinosaurs were in Japan, along with the significance of the discovery.

Challenge the problem!

First, let's take a look at the entrance exam questions about dinosaurs.

Problem

Select the stratum of the age when the fossils of dinosaurs are found

A 10,000 years ago B

100,000 years ago

C 1 million years ago D

10 million years ago

O 100 million years ago

Ka 1 billion years ago

(Aoyama Gakuin Middle School 2018 Science) )

The correct answer is Oh's "100 million years ago".

The first dinosaurs appeared 230 million years ago, and 66 million years ago, almost extinct.

Dinosaurs lived on the coast of Japan!

This time, a fossil that was found to belong to a new kind of dinosaur.

It was found by a local fossil lover in Nakagawa, Hokkaido in 2000.

Characteristic was a fossil of a large claw over 10 cm.

What kind of dinosaur statue did you see from this fossil?

It is more than 3 meters long and seems to have had long claws.

I tried to reproduce that figure in modern Hokkaido University.

Professor Yoshitsugu Kobayashi of the Hokkaido University Museum discovered that it was a new species.

While the Korona-ka could not be excavated overseas, he re-examined the fossils that had been found so far, and it is said that he came to the discovery.

Mr. Kobayashi, who is currently resuming research overseas, responded to an interview from Mongolia.

Mr. Kobayashi

"I named it Paralitherizinosaurus Japanix. Paralith means near the sea, the coast, and the Terizinosaurus that lived on the coast of Japan. Fossil dinosaurs from all over the world. Most of them have been found, but most of them are inland environments. It is very epoch-making that this Japanese dinosaur can draw the coastal scenery that was unknown all over the world. "

It was a "strange dinosaur"

What kind of ecology was this dinosaur living on the coast?

As a result of analyzing fossil nails, it was found to be Therizinosauria.

Therizinosauria fall into a large group called "theropods".

Here is the quiz.

Problem

What other dinosaurs do you think are this theropod?

A Triceratops with big horns

B Ferocious carnivorous dinosaur Tyrannosaurus

C Brachiosaurus with a long neck

The correct answer is Tyrannosaurus.

This group is primarily bipedal, mostly "carnivorous" dinosaurs like Tyrannosaurus.

However, this dinosaur is said to be different.

Mr. Kobayashi

"Paralitherizinosaurus is a strange dinosaur that has become a vegetarian and a dinosaur that eats plants."

This was supported by the "protrusion" at the base of the nail.

This is a feature not found in other theropods.

Mr. Kobayashi explained by using the handset as a nail.

Mr. Kobayashi

"There is a bulge under this claw and even if I try to bend it, this bulge will get caught and my fingers will not bend. The fact that the claws hardly move is a new feature of this Paralitherizinosaurus."

Normally, in carnivorous theropod hunting, the claws are swung up and all joints are moved to speed up and shake off.

The fact that the claws do not move is not considered to have been used for hunting.

Then, it is a quiz again.

Problem

What was the non-moving nail used for?

A to hide a big body

B to intimidate the opponent

C to pull his stuff

The correct answer is to pull things in.

It is believed that claws were used like a rake to pull the branches of a tree to the mouth.

Mr. Kobayashi

"This Therizinosaurus is a dinosaur that is not good at running because it has a hungry stomach. I think it's a mechanism that can be pulled in firmly. "

There is an image that a strong and carnivorous dinosaur is the final form of evolution.

However, according to Mr. Kobayashi, it is an evolution that dinosaurs, which were carnivorous, began to eat plants.

Mr. Kobayashi

"I think that things that could coexist with the environment have evolved. This time, Therizinosaurus does not show that it was able to prosper in Asia by changing to a herbivorous diet. I think it's true. "

Dinosaurs are still alive!

??

Dinosaurs, including Therizinosauria, have continued to evolve and prospered for approximately 160 million years.

However, 66 million years ago, a meteorite collision brought a long winter to the earth.

When I asked Mr. Kobayashi if the evolving dinosaurs couldn't adapt to the sudden changes so far, an unexpected answer came back.

Mr. Kobayashi:

"Dinosaurs that have been shaped and transformed into birds, and dinosaurs that have feathers on their bodies and have wings, have survived the meteorite impact and are still alive. That's how dinosaurs are still alive. That's why I'm alive. That's why I'm eating grilled dinosaurs, not grilled birds. Eyeballs are also dinosaur eggs. "

When I looked it up, the homepage of the Fukui Prefectural Dinosaur Museum also said, "Birds are now considered to be included in some theropods, so there are still about 10,000 species of dinosaurs around the world. It will be. "

Mr. Kobayashi talked about how creatures evolve into various types in this way.

Mr. Kobayashi

"Even if there is some change in the environment and everyone disappears, if we can evolve into various types, there will actually be things that survive, so it is very important to maintain diversity."

Finally, I asked him if he didn't know the fossil "bulge" that led to the discovery of the new species when the fossil was discovered more than 20 years ago.

Regarding this, Mr. Kobayashi said, "Research has progressed in the last 20 years, and now that I have seen various fossils, I noticed the" bulge ". It was the necessary 20 years."

In recent years, new fossils have been discovered one after another in Japan.

As we are at the forefront of dinosaur research, I would like to continue to pay attention to new research results originating in Japan.

In "Migake, Curiosity!" Of "Weekly Maru-Knowledge News" (broadcast at 8:25 am on Sunday), we will delve into the news every week on the subject of current affairs given in the entrance examination.

Let's think of "why?", In fact, "in the first place" that you want to know as a Kamakura caster.

You can also review the past on the homepage of the corner.

Please take a look from the link below.

https://www3.nhk.or.jp/news/special/maruwaka-migake/