Scientists find a new kind of ammonite in Japan

Scientists in Japan have found a new kind of ammonite^*1. The fossil^*2 came from rock layers in Tomamae and Haboro. These are two towns in the northwest of Hokkaido, a large island in the north of Japan. The rock layers are about 86.3 million to 83.6 million years old.

The Fukada Geological Institute, a research institute^*3 in Japan, announced the discovery on August 31, 2026. Daisuke Aiba, a researcher at the institute, studied the fossil. The ammonite had a shell with an unusual shape. It was a new genus^*4 and a new species^*5. Aiba gave it the name Heterocarinella japonica^*6.

Aiba used a CT scan^*7 to look inside the shell. The scan showed that the new ammonite belongs to a family called Turrilitidae^*8. People have studied fossils in Japan for about 150 years. In all that time, no one had found a new genus of this family in Japan before.

The discovery also changes what scientists know about this family. They thought that the Turrilitidae died out about 93.9 million years ago. But this fossil shows that some of them lived about 10 million years longer. They lived near the place that is now Hokkaido. There were far fewer kinds of them than before. Aiba says the area around Hokkaido may have been a safe place for ammonites at that time.

Aiba wrote a paper about the fossil. It appeared in the journal^*9 Paleontological Research on August 29, 2026.

1. *1 ammonite: a sea animal with a shell that lived millions of years ago
2. *2 fossil: the hard remains of an animal or plant from long ago, kept in rock
3. *3 research institute: a place where scientists work and study things
4. *4 genus: a group of closely related species
5. *5 species: one kind of animal or plant
6. *6 Heterocarinella japonica: the science name of the new ammonite
7. *7 CT scan: a way to take pictures of the inside of something with a special X-ray machine
8. *8 Turrilitidae: the name of a family of ammonites
9. *9 journal: a magazine where scientists print their studies