The young Colombian scientist Rubén Darío Vanegas left his home in Villavieja, a small municipality next to the Tatacoa desert in the department of Huila, one day in July 2020, with the idea of setting camera traps in the tropical dry forest that still is preserved in the region. He, his brother Andrés and two other friends who work in the Natural History Museum of La Tatacoa They wanted to know what species of animals inhabited that area of the desert, far from tourism. Along the way they came to an archaeological site where years before they had found fossils of fish and crocodiles. They decided to split up to explore it again. Each took a different course. Rubén, 26, saw a huge alligator tooth in the distance and decided to walk in that direction. “Next to it there were many small turtle fragments, yellow and brown,” he recalls in dialogue with EL PAÍS, “the turtle was almost complete. I began to collect and store the bits in three special bags, I took the coordinates and some photographs, I wrote down all the terrain data in my notebook and took them to the laboratory”.
The laboratory where Rubén took the turtle fragments is next to his house. It’s called Valerie Anders, after the wife of a NASA Apollo 8 astronaut who donated the money to build it. It is the second best paleontology laboratory in Colombia, above many universities and research centers. Rubén returned happy from his excursion and started working. “When doing comparative anatomy with the current turtles of the Magdalena River, I noticed that they were very similar, but they were not the same. I began to review part by part. Rubén, who defines himself as a paleontological heritage lookout in the desert and has been looking for fossils since he was 10 years old, discovered that the pieces could be put together like a puzzle, because each part fit perfectly with the next. “The museum did not have the fossil of any similar turtle, so I set myself the goal of assembling it to exhibit it. I spent all of December 2020 on that process, ”he recalls. The little turtle was complete, the shell even retaining the bite of a crocodile.
The museum had a new member, but neither Rubén nor his brother Andrés knew exactly what they had found. They called Professor Edwin Cadena, a doctor in paleontology and director of the Earth System Sciences program at the Universidad del Rosario in Bogotá. “For decades I have dedicated myself to the study of fossil turtles from the north of South America,” he explained to EL PAÍS by telephone. When Rubén told him about the find, they both got excited. Cadena traveled to the desert to see the fossil. When he saw it, he was surprised and decided to take all the material to the university to analyze it in detail. “After a few days he sent us an email saying that we had discovered a new species for science,” Rubén recalls happily.
At that time they began a scientific research process in which Cadena and Rubén worked together for more than two years and which concluded last week with the publication of an article in the specialized magazine geodiversites, confirming the relevance and originality of the finding. The new species is called Podocnemis tatacoensis, in honor of the family of turtles to which it belongs and the desert where it was found. According to the publication, the species inhabited the northern part of South America 13 million years ago, during the geological epoch called the Middle Miocene. It is the oldest record in the country of the genus of the turtle podocnemis or river turtle, as it is commonly known.
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The landscape of 13 million years ago was very different from that of now. The Andes mountain range had not finished forming and the great rivers did not exist. Instead, there were a series of interconnected flat surfaces, with many swamps, lakes, and small rivers. The now desert of La Tatacoa, where the turtle that Rubén found and the crocodile that attacked it lived, was a fluvial system and not a dry area, explains Cadena. The new fossil, the scientists agree, helps to understand the paleofauna that inhabited the humid tropical forest of the area. “We are trying to tell that story bit by bit to understand how we got to where we are today. Each fossil helps us to relate the parts of that ecosystem”.
For Professor Cadena, what is impressive about this fossil is that it preserved a series of “foramina”, orifices located exactly at the junction between the shell and the lower part of the turtle. “Those little holes are like the fingerprints of turtles. They allowed us to establish the family to which it belongs and confirm that it is a new species”, he explains. Today there are six species of turtles from the same family in rivers such as the Amazon, the Orinoco and the Magdalena, which are in danger of extinction. “Ancient fossils similar to current species help us to reconstruct their evolutionary history and, at the same time, allow us to send a conservation message,” explains Cadena.
These turtles are at risk due to excessive hunting, trafficking in their eggs and the destruction and contamination of their habitat. “This fossil makes a small contribution to conservation because it allows us to reach many communities and tell them that the turtles that are now on the brink of extinction have inhabited the area for 13 million years,” Rubén says hopefully. And he adds: “It cannot be that in a few decades humans will end a species.”
Professor Cadena agrees. “It is difficult to create awareness of preservation in the communities and residents close to the environments where these turtles live if we do not know their history. Knowing that these turtles have inhabited our country for millions of years and that in just a few decades we could put an end to this long evolutionary journey that they have had is, without a doubt, a reason to rethink before hunting them or destroying their ecosystems.”
Rubén says that the fossil of the turtle is exhibited in the Natural History Museum of La Tatacoa so that anyone can see it. “Here we have the only fossil dolphin that has been found in Colombia. There are mastodon teeth and giant sloth claws seven meters long.” They also have bones from the ancestor of the guinea pig, the skulls of the two largest freshwater turtles that have inhabited the planet, the remains of a glyptodont, an animal like the ones in the movie. The ice Ageand the most complete alligator fossil in South America.
The fauna that inhabited the region 13 million years ago contrasts with what is shown by the camera traps that Rubén and his friends set up the day they were found. The recordings reveal that in the tropical dry forest of the desert there are ocelots, raccoons, anteaters, deer, wild pigs and many other species that, like the turtle, need to be conserved.
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