World's oldest turtle fossil confirmed in Ishikawa

August 20, 2011

By KATSUHIRO IGATA / Staff Writer

Two fossils discovered in 1994 in Hakusan were confirmed recently as being that of a new genus and species of the Trionychidae family of soft-shell turtles, and about 20 million years older than what had been the oldest turtle fossil of that family discovered until now.

The fossils were found in the Tetori stratum group in the Kuwajima district of Hakusan, according to officials of the Hakusan board of education in Ishikawa Prefecture, who announced the confirmation. The stratum is from the early Cretaceous period, dating about 130 million years ago.

The fossils were part of a shell, measuring between one to three centimeters.

The fossils were discovered by Masatoshi Okura, an amateur researcher living in Aichi Prefecture, in a stratum about 300 meters from the Kuwajima fossil bluff that has been designated as a natural monument by the central government.

The turtles are believed to have been about 15 centimeters long and likely lived in small rivers.

The fossils were analyzed by Ren Hirayama, a paleontology professor at Tokyo's Waseda University.

According to Hirayama, there are no signs of scales on the shell surface that is a general characteristic of turtles. While that makes it closer to the Trionychidae family, there were also harder parts along the edge of the shell that are not commonly found in that family.

For that reason, the fossils are believed to be from a species that was somewhere in the process of breaking off from the turtle family and evolving into the Trionychidae family.

The new species of the fossil was given the scientific name of Kappachelys okurai. Kappachelys takes part of its name from the "kappa," a legendary water sprite commonly found in Japanese folklore.

The okurai part of the name is in honor of the individual who discovered the fossil.

By KATSUHIRO IGATA / Staff Writer
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Fossils confirmed as being the world's oldest for soft-shell turtles (The Asahi Shimbun)

Fossils confirmed as being the world's oldest for soft-shell turtles (The Asahi Shimbun)

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  • Fossils confirmed as being the world's oldest for soft-shell turtles (The Asahi Shimbun)

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