The remains of plants have been mistakenly identified as turtles in an uncommon case of misidentification.
According to researchers, two small, oval fossils originally believed to be ancient plants are in fact the preserved remains of young sea turtles.
Fossils from the middle of the 20th century, discovered in Colombia by Padre Gustavo Huerta who had a strong interest in fossilized plants, were found in rocks that date back to 132-113 million years ago.
At first, it was believed that the fossils belonged to a type of sphenophyllum, a plant that is now extinct and similar to present-day “horsetails.” The leaves were thought to be divided into wedge shapes and had veins extending from their bases. However, this has since been determined to be incorrect by experts.
“While examining the fossils again, our focus was on locating leaf veins. However, we discovered a fragile layer of spongy bone tissue instead. This led us to conclude that the fossils did not belong to plants,” explained Professor Edwin Cadena, a co-author of the research from Universidad del Rosario in Bogotá.
“Rather than that, we started to make comparisons with vertebrate fossils and were immediately reminded of images of hatching turtles.”
In a publication for Palaeontologia Electronica, the group detailed their analysis of the fossils in relation to present-day marine turtle specimens and fossils of a different sphenophyllum species.
The team has announced that the oval fossils, which measure 5cm and 6cm in length, are actually the carapaces, or hard shells, of marine turtles. Upon further examination, it was discovered that what was initially believed to be veins of leaves are actually bone growth patterns. Additionally, there is evidence of bones within the shell, known as neurals and costals, as well as noticeable serrated joints between them.
The scientists suggest that the turtles were likely under a year old and potentially belonged to the species Desmatochelys padillai. This particular species was a type of protostegid, a group of marine turtles that are now extinct and were known to include some of the largest ever recorded.
Yet, as a tribute to the initial confusion, the group has affectionately called them “Turtwig,” in reference to a Pokémon creature that combines features of a turtle and a plant.
Dr. Nick Fraser, a vertebrate paleontology expert at National Museums Scotland, who was not part of the research, stated that the revised interpretation is more logical. This is because sphenophyllum existed in the Paleozoic era, while the deposits where the fossils were discovered are from the later Mesozoic era. Cadena compared this disparity to mistakenly claiming that dinosaurs and mammoths coexisted.
Fraser stated that the new interpretation holds equal significance and he believes that their identity as hatchling turtles is accurately depicted. These early stage turtles are uncommon in the fossil record and further investigations, such as CT analysis, could potentially provide useful insights for species identification.
Andy Gale, a professor of geology and paleontology at the University of Portsmouth, stated with confidence that the specimens were baby turtles, not plants. He noted that this was a unique case of misidentification, emphasizing the common tendency to see what we desire rather than what is actually there.