The fossils, measuring 5 and 6 centimeters in size, were found in Colombia in the mid-20th century. At the time it was assumed that these were fossils of sphenophyllales, an extinct fern-like plant species.
But when researchers from the Universidad del Rosario in Bogota examined the fossils more closely, they discovered a fine layer of spongy bone tissue. So it cannot be a plant fossil.
The researchers then decided to compare the fossils to vertebrate fossils. It soon turned out to be the shells of small turtles. What first appeared to be leaf veins were actually patterns of bone growth.
The turtles were probably less than a year old and may have belonged to an extinct species of turtle that could grow to enormous sizes. The age of the rocks in which the fossils were found ranges between 113 million and 132 million years old.
The fossils have been named “Turtwig”, after a Pokémon that is half plant and half turtle. The research was published in the journal Electronic fossils.
