Scientists from the Royal Tyrrell Museum of Palaeontology in
Researcher Darla Zelenitsky, a geoscientist at the
It was nearly by accident that scientists recognized that the fossil turtle had been pregnant. "The real reason we knew she was pregnant was since when the fossil was found the body was broken down," Zelenitsky told LiveScience, "therefore there was egg shell on the ground immediately below the fossil, it was falling out of the body".
The team spotted at least five crushed eggs inside the body of the fossilized female, and computed tomography (CT) scans discovered more eggs concealed beneath the turtle's shell. The turtle, expected to be about 16 inches (40 cm) long, could have produced about 20 eggs. When still intact, the eggs would have been sphere-shaped and about 1.5 inches (4 cm) in diameter. The eggs from the close by nest were about the same size and form. Both sets of eggs as well had very thick and hard shells, particularly relative to most modern turtles whose shells are moreover thinner or soft.
The thick eggshell can have evolved to look after the eggs from drying out or from greedy predators that lived during the Age of Dinosaurs. The pregnant turtle and nest specimens, the researchers say, shed light on the growth of reproductive traits of current turtles. François Therrien, the Museum's Curator of Dinosaur Palaeoecology, who worked on the turtle report in the journal said that "Based on these fossils, we have firm that the ancestor of living hidden-necked turtles, which are nearly all of today's turtles and tortoises, laid a big number of eggs and had hard, rigid shells".