Solution to the mystery: The fossil plant turns out to be a fossil turtle

Between 1950 and 1970, Padre Gustavo Huertas collected fossils around his hometown of Villa de Leyva, 100 miles northeast of Bogotá, Colombia. He took it seriously and also cataloged his discoveries. Two round stones, with a pattern of lines reminiscent of tree leaves, were thought to be fossils Sphenophyllum columbianum It was formed in the Early Cretaceous period, between 132 and 113 million years ago. The excavations ended up at the National University of Colombia in Bogotá.

How wonderful it would have been to find fossils of this plant at that site, Fabiani Herrera, assistant curator of fossil plants at the Field Museum in Chicago, thought years later. Other known members of the genus Sphenophyllum It became extinct 100 million years ago. Little work on ancient plants had been done in Colombia, so Herrera decided to take a closer look at the fossil.

It turns out they are not fossils Sphenophyllum columbianum He is. In fact, it turns out they’re not plant fossils at all. The fossils are turtle shells, and were published in the scientific journal on Thursday Electronic fossils To read.

Not too crazy

At a glance, the fossils look a bit like tree leaves Sphenophyllum “So Huertas’ rating wasn’t that crazy,” Herrera wrote in a press release. But the lines weren’t really plant-like, they were more like bones.

“When I saw the pictures, I quickly thought it was a turtle,” says Edwin Alberto Cadena, a paleontologist who specializes in turtles at the University del Rosario in Bogotá and a friend of Herrera. “I didn’t notice the size of the pictures until a moment later.” The fossils are about 5 cm in diameter. “They’re small. Very, very small.”

The turtle expert was also initially surprised by the disappearance of the typical markings that could be seen on the outside of the turtle. “We realized we were looking inward.”

There are no strong bones yet

To determine the age of the turtles, Cadena and a doctoral student examined the thickness of the shell and where the ribs meet. Since the baby turtles don’t yet have strong bones, researchers suspect they didn’t just hatch from the egg. The slightly developed carapace indicates that they are between 0 and 1 year old.

“It’s very special to find baby fossil turtles,” Cadena says in the press release. “The bones in baby turtle shells are very thin, making them easy to destroy.”

Its rarity makes it a fitting find. “These turtles are likely relatives of other Cretaceous species that can reach 50 feet (15 meters) in length, but we know little about how they actually grew to such huge sizes,” Cadena says.

“We were able to solve a little mystery related to ancient plants,” Herrera says. “But more importantly to me, this study shows the need to re-examine historical collections in Colombia. For the Early Cretaceous, it is a critical time in the evolution of land plants.

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