68-Million-Year-Old Egg

In 2011, Chilean researchers unearthed something on Seymour Island near Antarctica that resembled a deflated football. It was leathery and wrinkled, was about 11 by 8 inches in size, and not knowing what it was, they nicknamed it “The Thing.”

Now, after years of analysis, scientists say it is a soft-shelled egg from 68 million years ago. The creature that laid it was a large sea lizard (mosasaur) and the egg is known as Antarcticoolithus bradyi. The discovery stunned paleontologists because it was the largest soft-shelled egg ever found, and the second-largest egg of any known species.

This egg had a thin, flexible shell that resembles modern snake eggs. It is from an animal as large as a large dinosaur, but it’s not a dinosaur egg. It reveals information about ancient marine reptile reproduction.

The likely mother was a giant mosasaur, and skeletal remains of a Kaikaifilu hervei was found near the egg. Scientists estimated her size to be at least 23 feet long, excluding the tail. Mosasaurs were apex predators and related to today’s monitor lizards.

The site held more than one deflated egg. Fossilized remains of juvenile and adult mosasaurs and plesiosaurs suggest the area functioned as a prehistoric nursery, painting a vivid picture of ancient parenting.

Recent discoveries of soft-shelled eggs of Protoceratops and Mussaurus dinosaurs reveal that flexible shells were more common than believed. One scientist said that hard shells weren’t ancestral; they evolved independently. The race to understand prehistoric reproduction has begun.

Did mosasaurs lay eggs in the ocean, and they hatched almost immediately, like modern sea snakes? Or did they deposit eggs on beaches? The mosasaur’s massive size and weight implies beach nesting was unlikely.

Antarctica’s harsh conditions make it remarkable that such a delicate egg fossilized at all. That it did suggests ideal sediment and climate for fossilizing soft tissue, which usually degrade rapidly. Antarctica is becoming increasingly important because it may hold countless fossils that can reveal secrets about ancient life.

Further Antarctic expeditions are being planned as scientists hope to see how widespread this reproductive behavior was among marine reptiles. Did plesiosaurs use similar strategies? How many other eggs are waiting under the ice?

The mystery of “The Thing” has rewritten scientific understanding of marine reptile reproduction and challenged assumptions that had been held for generations.

 

https://www.msn.com/en-us/news/technology/scientists-found-a-giant-68-million-year-old-egg-and-the-thing-inside-could-rewrite-prehistoric-life/ss-AA1T7Smh?ocid=hpmsn&cvid=6950143722104be99bc51f41a022ee18&ei=47#image=10