In 2011, Chilean scientists discovered a very rare fossil egg in Antarctica, resembling a deflated soccer ball
For nearly a decade, the specimen remained untagged and unstudied in the collections of the National Museum of Natural History in Chile, and scientists identified only by his nickname inspired by the science fiction movie: The Thing ( “The Thing”) .
Now, a new study led by researchers at the University of Texas and also published in Nature , has revealed that these remains are actually a giant soft-shell egg from about 66 million years ago.
Measuring more than 28 centimeters long by 18 wide, and weighing more than 6.5 kilos, it is the largest soft shell egg ever discovered and the second largest egg of any known animal.
Is it a dinosaur egg?
In addition to its astonishing size, the fossil is significant because scientists believe it was put in by an extinct giant marine reptile, such as a mosasaur, a large predator related to forked-tongued lizards like Komodo dragons and snakes.
“It is an animal the size of a large dinosaur, but it is completely different from a dinosaur egg,” says lead author Lucas Legendre, a postdoctoral researcher at the Jackson School of Geosciences at UT, who adds: “It is very similar to eggs of lizards and snakes, but it is from a truly giant relative of these animals ».
Identifying The Fossil Egg
Using a set of microscopes to study samples, Legendre found several layers of membrane that confirmed that the fossil was actually an egg.
The structure is very similar to the fast-hatching transparent eggs that some snakes and lizards lay today, they explain.
However, because the fossil egg is hatched and contains no skeleton, Legendre had to use other means to focus on the type of reptile that laid it.
He collected a dataset to compare the body size of 259 living reptiles with the size of their eggs, and found that the reptile that laid the egg would have been more than six meters long from the tip of its snout to the end of its body, not counting a tail.
Both in size and in the relationships of live reptiles, an ancient marine reptile meets the requirements.
In addition to that evidence, the rock formation where the egg was discovered also houses skeletons of baby mosasaurs and plesiosaurs, along with adult specimens.
“Many authors have hypothesized that this was a type of nursery with protected shallow water, a cove environment where young people would have had a quiet environment to grow,” says Legendre.
The document does not go into how the ancient reptile could have laid the eggs.
However it is believed that it could be due to the hatching of the egg in open water, which is the way in which some species of sea snakes give birth, or that the reptile lays the eggs on a beach and the young return to the ocean like the young of sea turtles.
It would depend on some maneuvering by the mother because the giant marine reptiles were too heavy to support their body weight on land.
Source: UT Jackson School of Geosciences .