Six types of fossils of new species of shellfish that lived in the dinosaur era more than 100 million years ago were found in the rocks stored in the museum in Chiba City.

This rock was donated by a fossil collector in the prefecture 22 years ago to be useful for research.

What was discovered was a small fossil snail, about 1 to several millimeters in size, all six of which are new.

Senior Researcher Izaji Koji, who studies paleontology at the Chiba Prefectural Central Museum, took it out of a rock of about 50 cm stored in the storage.

This rock was found by Katsuhiko Yamada, an amateur fossil collector living in Choshi City, Chiba Prefecture, on the local coast, and was donated to the museum 22 years ago because there was something like an ammonite fossil on the surface. did.



According to the museum, on the coast of Choshi City, there are exposed strata of the Early Cretaceous period when dinosaurs lived more than 100 million years ago, and sometimes ammonites, shells, shark teeth, etc. It means that you can find fossils.



Mr. Yamada said, "The waves on the coast of Choshi are rough, and even large rocks are washed away and lost, so I thought I would use it if I could store it and use it for research and education."



The donated rocks have been stored in the storage for a long time because it is laborious to manually remove the fossils, but Mr. Izaji came up with the idea of ​​applying a method of immersing the stones in chemicals to dissolve them. ..



When the stone was broken into small pieces and soaked, it turned into a mud-like state in a few days, and by washing away the mud, the small fossils could be taken out cleanly.



According to Mr. Osamu Iza, this discovery has revealed hints that lead to the mystery of the evolution of snails and the biodiversity of the Cretaceous period.



Mr. Osamu Iza said, "Because I kept the stones, I was able to come up with a new method and lead to new discoveries."

Of the six types of snail fossils discovered this time, one was named "Pseudomelania Yamadai" after Mr. Yamada.



With this discovery, the museum is hoping that new fossils may be discovered in other materials stored in the museum.