120-Million-Year-Old Fossil Misidentified as Plant, Recognized as the First Hatchling Marine Turtle From Aptian Age

Occasional cases of mistaken identity can sometimes happen during scientific studies, especially when experts try to figure out what is in a fossil. These petrified remains can resemble a completely different creature after spending millions of years tucked away in rocks.

Wrongly Identified Creature

From the 1950s to the 1970s, Colombian priest Padre Gustavo Huertas had the habit of collecting rocks and fossils near a town called Villa de Levya. In one of his searches, he discovered two fossils in the Paja Formation which is part of one of Colombia's geological heritage sites called the Marine Reptile Lagerstätte of the Ricaurte Alto.

The site was home to previous fossil discoveries such as the remains of turtles, ichthyosaurs, pliosaurs, plesiosaurs, dinosaurs, and crocodile relatives called crocodylomorphs. These creatures date back from the Early Cretaceous Period.

The specimens found by Huertas were small, round rocks with lines that looked like leaves, so he classified them as a type of plant fossil. He described them in 2003 as Sphenophyllum colombianum.

Some scientists, however, were surprised to hear that the plant dated between 113 and 132 million years ago was discovered in South America. According to the fossil record, an extinct plant which was once prevalent around the planet died out over 100 million years earlier.

Earlier research about the plant showed that its leaves were wedge-shaped with veins that radiate from the base of the leaf. The age and location of the specimen also intrigued Héctor Palma-Castro from the National University of Colombia and Fabiany Herrera, the assistant curator of paleobotany at Chicago's Field Museum of Natural History.

The two fossils, measuring 2 inches (5 centimeters) in diameter, were kept at the National University of Colombia's department of geosciences. As Herrera and Palma-Castro examined and photographed the petrified remains, they thought something seemed strange. Looking at them in detail, the lines seen on the fossils do not look like the veins of a plant, but they are most likely bones.

Solving a Fossil Mystery

Herrera informed his colleague Edwin-Alberto Cadena, a paleontologist studying turtles and other vertebrates at Del Rosario University in Colombia. From the photos sent to him, Cadena recognized the fossil as a carapace or the bony upper shell of a turtle. What makes it even more remarkable is the fact that it is not only a turtle, but a hatchling specimen.

When the shells were analyzed, the researchers determined that these were about one year old at the most when they died. As baby turtles develop, their growth rates and sizes can vary. It is also rare to find remains of young turtles because the bones in their shells are so thin.

The turtle species was also named 'Turtwig', after a Pokémon character that is half-turtle, half-plant. They were also likely relatives of other Cretaceous species that were up to 15 feet (4.6 meters) long, although it remains a mystery how they actually grew to such giant sizes.

The research team did not blame Huertas for mistakenly identifying the fossils as plants. What he believes to be leaves and stems were actually vertebrae and rib bones within a turtle's shell.