The oldest known anuran trackways found in Jinju

The world’s oldest trackways of anuran (frog) were found in Jinju, South Gyeongsang Province.

A research team led by Kim Kyung-soo, director of the Korea Geological Heritage Research Center, Im Jong-deok, a researcher of Cultural Heritage Administration, and the research team led by Kim Dong-hee of the National Science Museum discovered 22 frog tracks from the Cretaceous Jinju Formation of the Mesozoic Era in Jinju Innovation City, and published the findings on Dec. 12 in Cretaceous Research.

The team found hopping mammal fossils for the first time in the world in 2017 and traces of bird-sized raptor dinosaur this year in Jinju. Thinking that there will also be trackways of frogs, they started looking at the existing fossils again.

As a result, they discovered three sequenced footprints on a shale sample named “HTB-043.” Professor Kim put a frog on a mud to see how it leaves footprints and compared them to the footprint patters on the fossil to find out that the trackways belonged to a type of anuran from 110 million years ago.

“The distance between the first footprint of a hind leg and the next was 10-20 centimeters,” said Professor Kim. “It is presumed that they hopped (like the frogs of the present time).”


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