Machikane Crocodylidae (Toyotamaphimeia Machikanensis) fossil designated as registered monument

The Council for Cultural Affairs approved the designation of Machikane Crocodylidae (Toyotamaphimeia Machikanensis) fossil housed and displayed by The Museum of Osaka University as a registered monument. The Machikane Crocodylidae fossil was the first complete fossil skeleton of this crocodylidae dating from about 420, 000 years ago found in Japan. The crocodile's skull is 1m long and its estimated overall length is 6.9 ~ 7.7m.

The crocodile fossil was discovered accidentally in a some 420,000 year-old layer of earth in May 1964, during the construction of the School of Science on the Toyonaka campus of the University of Osaka. Judging from the analysis of pollen found in the layer of earth, it is estimated that the climate was temperate when the crocodile lived. This Machikane Crocodylidae fossil has played an important role in the study of the evolution of crocodiles.

Machikane Crocodylidae fossil, 3F, Machikaneyama Shugakukan, The Museum of Osaka University

A replica of the Machikane Crocodylidae fossil is displayed in the lobby of the Machikaneyama Shugakukan, The Museum of Osaka University.

The University of Osaka mascot Dr. Wani

The age of the Machikane Crocodylidae (Toyotamaphimeia Machikanensis) fossil has previously been described as “approximately 450,000 years ago.”
Based on the notice below from the Museum of Osaka University, it has been revised more accurately to “approximately 420,000 years ago.” (Updated on June 4, 2026)

Related events

In this 50th year since the discovery, the University of Osaka is holding special Machikane Crocodylidae events. More information will be posted on the university's website.

• Exhibition: the miraculous ancient crocodile Machikane Crocodylidae (Museum of Osaka University, July 26 ~ August 30)
• Summit 2014: Commemorative symposium, Machikane Crocodylidae (Toyonaka City Aqua Bunka Hall, 11/16)

Related publications

• Public relations magazine, Handai NOW #140, April 2014 issue , Public Relations Division, The University of Osaka
• Machikane Crocodylidae (Toyotamaphimeia machikanensis) Fossil , The University of Osaka Press
• The Japanese Crocodile Awakens from his Sleep , PHP Inc.

Related Links

Announcements from the Museum of Osaka University
Revision of the age description of the Machikane Crocodylidae (Toyotamaphimeia Machikanensis) fossil