Unveiling Turtwig: Exploring the Surprising Origins of an Ancient Turtle Species
Unraveling an ancient mystery: Fossil analysis reveals two leaf-like structures, previously misidentified, are actually rare baby turtle shells from South America, shedding light on prehistoric life during the time of dinosaurs
Subscribe to CNN's Wonder Theory science newsletter and delve into the mysteries of the universe with the latest news on captivating discoveries, scientific progress, and more. Discover how recent research has unveiled that the ancient plant fossils, which had perplexed scientists, are actually not plants at all.
The small round shapes with a leaflike pattern were once the shells of baby turtles that lived during the time of dinosaurs. Scientists have nicknamed the turtle species "Turtwig," after a Pokémon character that is half-turtle, half-plant. This discovery is the first time baby turtle carapaces have been found in northwestern South America, according to the study authors.
Their research findings were released on Thursday in the Palaeontologia Electronica journal.
Héctor Palma-Castro, a graduate student of paleobotany at the National University of Colombia and the lead author, stated, "In the world of Pokémon, various elements are combined, including animals, machines, and plants."
Decades ago, the initial classification of a fossil as a plant was later discovered to be a baby turtle, prompting thoughts of certain Pokémon such as Turtwig, a baby turtle with a leaf on its head. However, it required significant investigation to unravel this paleontological mystery.
Incorrect location, incorrect timing.
The story began when Colombian priest Padre Gustavo Huertas stumbled upon the fossils in the Paja Formation, a significant part of Colombia's geological heritage site known as the Marine Reptile Lagerstätte of Ricaurte Alto.
Fossils previously found at the site include dinosaurs, plesiosaurs, pliosaurs, ichthyosaurs, turtles, and crocodile relatives known as crocodylomorphs, dating back to the Early Cretaceous Period, between 113 million and 132 million years ago.
Fossilized Trisauopodiscus tracks (left) and modern bird tracks (right).
Abrahams et al.; 2023; PLOS ONE
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Between the 1950s and 1970s, Huertas gathered fossils and rocks near the town of Villa de Leyva. Initially, the leaf-patterned rocks were thought to be fossilized plants, and were later identified as Sphenophyllum colombianum in a 2003 study.
Scientists were taken aback to learn that the plant had been found in northern South America and was estimated to be between 113 and 132 million years old. This extinct plant, which used to be widespread, disappeared over 100 million years ago based on fossil evidence.
Earlier studies on the plant indicated that its leaves were generally wedge-shaped with veins spreading out from the base of the leaf.
Palma-Castro and Fabiany Herrera, the assistant curator of paleobotany at the Negaunee Integrative Research Center at Chicagos Field Museum of Natural History, were intrigued by the age and location of the fossils.
Herrera focuses on collecting and studying plants from the Early Cretaceous Period (100.5 million to 145 million years ago) in northwestern South America, an area that has been subject to limited paleobotanical research.
The two fossils, each around 2 inches (5 centimeters) in size, were stored in the collections of the geosciences department at the National University of Colombia. During their examination and photography of the fossils, Herrera and Palma-Castro noticed something unusual.
"As we looked closely, the markings on the fossils didn't resemble plant veins - I was convinced that they were likely bone," explained Herrera, the lead author of the study, in a statement.
Herrera reached out to his colleague Edwin-Alberto Cadena, a seasoned paleontologist and senior lecturer at Del Rosario University in Bogotá, Colombia, who specializes in the study of turtles and other vertebrates.
Cadena, a coauthor of the study, remarked, "They sent me the photos, and I said, 'This definitely looks like a carapace—the bony upper shell of a turtle.' 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.'"
An illustration of a sleeping alvarezsaurid dinosaur, Jaculinykus, like modern birds.
Seiji Yamamoto
Newly discovered dinosaur species found in a posture that provides insights into the evolution of bird behavior. Cadena and his student, Diego Cómbita-Romero at the National University of Colombia, analyzed the fossils alongside the shells of other ancient and contemporary turtles.
"When we first saw the specimen, I was amazed to find that the fossil was missing the typical marks on the outside of a turtle's shell," said study coauthor Cómbita-Romero in a statement. "It was slightly concave, resembling a bowl. We then realized that the visible part of the fossil was actually the inner side of the carapace, showing us the part of the shell that is inside the turtle."
In their analysis of the shells, the researchers concluded that the turtles were at most 1 year old when they died.
Young turtles can vary in their growth rates and sizes as they develop, according to Cómbita-Romero. However, it is uncommon to find remains of young turtles due to the thinness of the bones in their shells. Cadena stated that these turtles were probably related to other Cretaceous species that could grow up to fifteen feet long, but there is limited knowledge about how they achieved such gigantic sizes.
Huertas was not held responsible by the researchers for incorrectly classifying the fossils as plants. What he thought were leaves and stems turned out to be the vertebrae and rib bones found within a turtle's shell.
Henry Sharpe/Courtesy American Museum of Natural History
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"We have successfully solved a minor paleobotanical puzzle, and more significantly, this study emphasizes the importance of revisiting historical collections in Colombia. The Early Cretaceous period plays a crucial role in the evolution of land plants," Herrera stated. The next goal for the research team is to uncover the ancient forests that thrived in the region.
"Paleontology constantly challenges your imagination and capacity for awe," Palma-Castro stated. "Discoveries like these are exceptional as they not only broaden our understanding of the past, but also reveal the countless possibilities of what we can uncover."
