Antarcticoolithus
First fossil egg found in Antarctica, named 'The Thing'.
Antarcticoolithus is a genus of fossil egg, known from a single large specimen found in the López de Bertodano Formation on Seymour Island, Antarctica. The egg dates to the Maastrichtian stage of the Late Cretaceous. Its only species, A. bradyi, was formally named in 2020. Discovered in 2011 by a Chilean research team, it was the first fossil egg ever found in Antarctica. The researchers nicknamed it "The Thing" after the film. The egg measures 28 by 18 centimeters (11 by 7 inches).
The fossil is collapsed and folded, with a thin shell that has a layered structure but lacks a prismatic layer and distinct pores. In these features, it resembles the eggs of most modern lizards and snakes (Lepidosauria). Which animal laid it is unknown, but the egg's preserved traits match those of mosasaur skeletons found nearby. A phylogenetic analysis suggests the egg came from an individual at least 7 meters (23 feet) long, likely a giant marine reptile. The combination of a large egg and a relatively thin shell may point to a reproductive strategy linked to gigantism and lepidosaurian viviparity, where the egg is laid and hatches immediately. However, it is also possible the egg was laid by a dinosaur.
- Type
- Oogenus of fossil eggs
- Species
- A. bradyi
- Discovery year
- 2011
- Discovered by
- Chilean team of researchers
- Location
- Seymour Island, Antarctica
- Formation
- López de Bertodano Formation
- Size
- 11 by 7 inches (28 by 18 cm)
Lore & Background
The fossil egg is visibly collapsed and folded, characterized by a thin eggshell with a layered structure that lacks a prismatic layer and distinct pores. The oofossil is similar to that of most extant lizards and snakes (Lepidosauria). The identity of the animal that laid the egg is unknown, but preserved morphologies are consistent with skeletal remains of mosasaurs found nearby.
Reader's Guide
Antarcticoolithus represents the first fossil egg discovered in Antarctica, marking a significant paleontological find from the Late Cretaceous. Its thin, soft-shelled structure and large size—measuring 11 by 7 inches—suggest a reproductive investment linked with gigantism and lepidosaurian viviparity, where an egg is laid and hatches immediately. Phylogenetic analysis indicates the egg belonged to an individual at least 7 meters long, hypothesized to be a giant marine reptile, possibly a mosasaur. However, the possibility that it was laid by a dinosaur remains unresolved. The egg's discovery by a Chilean team in 2011 and its informal name 'The Thing' highlight its cultural and scientific impact, providing rare insight into the reproductive biology of ancient polar reptiles.
Did You Know?
- The fossil egg was discovered in 2011 by a Chilean team of researchers.
- The egg was named 'The Thing' in reference to the movie.
- The egg measures 11 by 7 inches (28 by 18 cm).
More in Fossils of Antarctica 1-24
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