A fossil thought for years to be a plant was really a baby turtle.
Now, researchers have nicknamed it “Turtwig” after a Pokemon character that’s half-turtle, half-plant.
For several years from the 1950s to the 1970s, a Priest named Padre Gustavo Huertas collected rocks and fossils near a town called Villa de Levya in Colombia.
Two of the specimens he found were small, round rocks patterned with lines that looked like leaves. He classified them as a type of fossil plant.
But for a new study, published in the journal Palaeontologia Electronica, researchers re-examined the “plant” fossils and found that they weren’t plants at all: they were the fossilized remains of baby turtles.
Héctor Palma-Castro, a paleobotany student at the Universidad Nacional de Colombia, said: “It was truly surprising to find these fossils.”
The plants in question had been described by Huertas in 2003 as Sphenophyllum colombianum.
The fossils come from Early Cretaceous rocks, dating back to between 113 and 132 million years ago, during the dinosaurs’ era.
Fossils of Sphenophyllum colombianum were surprising at that time and place as the other known members of the genus Sphenophyllum died out more than 100 million years prior.
The plants’ age and locality piqued the interest of Colombian-born Dr. Fabiany Herrera, the assistant curator of fossil plants at the Field Museum in the United States, and his student, Palma-Castro.
Dr. Herrera said: “We went to the fossil collection at the Universidad Nacional de Colombia in Bogotá and started looking at the plants, and as soon as we photographed them, we thought, ‘this is weird.’”
He said that, at first glance, the fossils, about two inches in diameter, looked like rounded nodules containing the preserved leaves of the plant Sphenophyllum.
But Dr. Herrera and Palma-Castro noticed key features that weren’t quite right.
Palma-Castro said: “We spent days searching through wooden cabinets for fossil plants.
“When we finally found this fossil, deciphering the shape and margin of the leaf proved challenging.”
Dr Herrera said: “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.”
So Dr Herrera reached out to an old colleague of his, Edwin-Alberto Cadena.
Professor Cadena, a paleontologist who focuses on turtles and other vertebrates at the Universidad del Rosario in Bogotá, Colombia, said: “They sent me the photos, and I said, “This definitely looks like a carapace’ – the bony upper shell of a turtle.”
When he saw the scale of the photos, Prof Cadena recalled: “I said, ‘Well, this is remarkable, because this is not only a turtle, but it’s also a hatchling specimen, it’s very, very small.”
Prof Cadena and his student, Diego Cómbita-Romero, further examined the specimens, comparing them with the shells of both fossil and modern turtles.
Cómbita-Romero said: “When we saw the specimen for the first time I was astonished, because the fossil was missing the typical marks on the outside of a turtle’s shell.
“It was a little bit concave, like a bowl.
“At that moment we realized that the visible part of the fossil was the other side of the carapace, we were looking at the part of the shell that is inside the turtle.”
Details in the turtle’s bones helped the researchers estimate how old it was at death.
Cómbita-Romero explained that turtle growth rates and sizes vary, so the research team looked at features such as the thickness of its carapace and the spots where its ribs were knitting together into solid bone.
He said: “This is a feature uncommon in hatchlings but observed in juveniles.
“All this information suggests that the turtle likely died with a slightly developed carapace, between zero to one-years- old, in a post-hatchling stage.”
Prof Cadena said: “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.”
The researchers say that the rarity of fossilised baby turtles makes their discovery an important one.
Prof Cadena said: “These turtles were likely relatives of other Cretaceous species that were up to 15 feet (4.57 m) long, but we don’t know much about how they actually grew to such giant sizes.”
The researchers don’t fault Padre Huertas for his mistake as they the preserved shells really do resemble many fossil plants.
But they explained that the features that Huertas thought were leaves and stems are actually the modified rib bones and vertebrae that make up a turtle’s shell.
Cómbita-Romero and Palma-Castro nicknamed the specimens as “Turtwig” – after a Pokémon that’s half-turtle, half-plant.
Palma-Castro said: “In the Pokémon universe, you encounter the concept of combining two or more elements, such as animals, machines, plants, etc.
“So, when you have a fossil initially classified as a plant that turns out to be a baby turtle, a few Pokémon immediately come to mind.
“In this case, Turtwig, a baby turtle with a leaf attached to its head.”
He added: “In paleontology, your imagination and capacity to be amazed are always put to the test.
“Discoveries like these are truly special because they not only expand our knowledge about the past but also open a window to the diverse possibilities of what we can uncover.”
Produced in association with SWNS Talker
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