An estimated 66 million years ago , an ancient leatherneck reptilian is believe to have leave a large , football - sized egg on Antarctica . It is the first known fossil soft - shell egg to have been go away on the continent and perhaps place by an ancient , extinct giant marine reptilian have sex as a mosasaur .
" It is from an animal the size of it of a large dinosaur , but it is wholly unlike a dinosaur egg , " say lead author Lucas Legendre , a postdoctoral research worker at the University of Texas Austin ’s Jackson School of Geosciences , ” in astatement . " It is most similar to the eggs of lizards and Snake , but it is from a rightfully elephantine relative of these brute . "
It was antecedently believed that giant marine reptiles from the Cretaceous did not lay eggs , yet “ nothing like this has ever been come across . ” Chilean scientist first came across the fogey nearly a decade ago , after which it sat unlabelled in the country ’s collections at the National Museum of Natural History . Scientists refer to the more than 28 - by-18 - cm ( 11 - by-7 inches ) Edward Durell Stone - like dodo but as “ The Thing ” .
Researchers pierced through the many bed of the egg ’s tissue layer using microscopes to determine that the fossil was an egg . The “ visibly collapsed and fold ” thinly - shelled egg is among the largest to have ever been described – second only to theelephant Bronx cheer ’s bollock – and its social structure is like to most extant lizards and snakes , which is significative of an ovoviviparous life-style whereby the egg develop inside of the female parent and hatches immediately after being laid .
However , the nut had already hatched ten of millions of years ago , mean whatever was once encased within it is long go . Though it is not clear what species laid the large egg , the researchers then compiled data of 259 living reptilian to compare ball to dead body size , suggesting that the fauna would have measured more than 6 meter ( 20 foot ) long from end to end , not including a tail : it may have been a giant marine reptile known as amosasauror perhaps by a yet - to - be - determined dinosaur species . Regardless , it represents a new taxonomic category : Antarcticoolithus bradyi .
“ Such a turgid egg with a relatively lean shell may ponder derived constraint associated with eubstance bod , reproductive investment linked with giantism , and lepidosaurian viviparity , in which a ‘ vestigial ’ bollock is laid and hatches immediately , ” write the study authors inNature .
Where the egg was found in the rock formation is also assure of the environment in which it think of in . Nearby , skeleton in the cupboard of both baby and adult mosasaurs and plesiosaurs have been find , suggesting that this area may have been a “ variety of baby’s room site ” characterized by a protect cove environment .
It is also not clear how the animal hatched . It could be that the female parent set the ball in undefended water in the same way as modernistic ocean snakes , or that the reptile wriggled its path onto the shore – it would have been too heavy to hold up its own body exercising weight – and used its tail to create a nest of kind before its hatchlings scurried out to sea like sea turtles today .
The finding have been published in collaboration with a second studydescribing howsoft - case egg may have evolvedover time .
