Once Thought to Be Plants, These Rare Fossils Are Actually Baby Turtles, Scientists Say

The prehistoric specimens found in Colombia could represent one of the oldest and largest turtle species to ever exist

two grey ovals that show a central vertical bone-like line with structures branching out to the sides
Two fossilized specimens, each less than 2.5 inches in length, were originally thought to be plants. Now, scientists say they are preserved hatchling turtles. Society of Vertebrate Paleontology, December 2023 under CC BY 4.0 DEED

Two small, oval-shaped fossils have spent the last 20 years officially categorized as an extinct plant. But now, in a study published Thursday in the journal Palaeontologia Electronica, scientists suggest they are something much rarer: prehistoric baby turtles.

The fossils had been misidentified by a priest named Gustavo Huertas, who found them near a Colombian town called Villa de Leyva sometime between the 1950s and 1970s. At that time, he thought their marked lines resembled the veins in plant leaves.

In 2003, Huertas categorized the fossils as Sphenophyllum colombianum, an extinct shrub thought to have died out at the beginning of the Triassic Period 251 million years ago. For a while, his assumption went unchallenged, despite one major contradiction: The two small fossils were aged between 113 million and 132 million years old, placing them alongside dinosaurs during the Early Cretaceous period—100 million years after the supposed extinction of Sphenophyllum colombianum.

It was this discrepancy that caught the attention of Fabiany Herrera, a paleobotanist and assistant curator of fossil plants at the Field Museum in Chicago. Along with paleobotanist Héctor Palma-Castro of the National University of Colombia, he decided to re-examine the fossils.

“We went to the fossil collection at the [university] and started looking at the plants, and as soon as we photographed them, we thought, ‘This is weird,’” says Herrera, the study’s senior author, in a statement. “When you look at it in detail, the lines seen on the fossils don’t look like the veins of a plant—I was positive that it was most likely bone.”

Herrera then contacted paleontologist Edwin-Alberto Cadena at the Universidad del Rosario in Colombia, who specializes in turtles.

“They sent me the photos, and I said, ‘This definitely looks like a carapace’—the bony upper shell of a turtle,” says Cadena in the statement. “This is remarkable, because this is not only a turtle, but it’s also a hatchling specimen—it’s very, very small.”

He and Diego Cómbita-Romero of the National University of Colombia then compared the specimens to both fossilized and modern turtle shells. Further examination led them to hypothesize that the fossils could be hatchlings of Desmatochelys padillai—one of the oldest and largest turtles to ever exist.

“Considering that the fossil hatchlings were found in the same rocks where one of the most complete and oldest marine turtles from the Early Cretaceous has been discovered, known as Desmatochelys padillai, we believe that these hatchlings could correspond to this extinct species,” Cadena tells Popular Science’s Laura Baisas.

While the two fossils in question are each less than 2.5 inches long, Desmatochelys padillai could grow more than six feet in length. The researchers suggest that the specimens were less than a year old at the time of death, and they say the lines Huertas thought to be the veins in leaves are likely bone growth patterns.

“This is actually really rare to find hatchlings of fossil turtles in general. When the turtles are very young, the bones in their shells are very thin, so they can be easily destroyed,” Cadena says in the statement.

Nick Fraser, an expert in vertebrate paleontology at National Museums Scotland who was not involved in the study, tells the Guardian’s Nicola Davis that the fossils’ new classification makes more sense. “Their identity as hatchling turtles looks spot-on to me,” he says to the publication.

In homage to the misidentification as plants, the team has given the fossils a unique nickname. They’re calling the specimens “Turtwig,” after the Pokémon universe’s baby turtle with a leaf atop its head.

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