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Big-Eyed Dinosaurs Foraged in Polar Australia’s Darkness

Their excellent night vision and apparent warm blood raise a question: Could they have survived icehouse conditions at the end of the Cretaceous period?


DINOSAURS flourished in southeastern Victoria during the Early Cretaceous, when the region lay within the Antarctic Circle. This mural depicts six species that left fossils there and a seventh—the large iguanodontid Muttaburrasaurus—that has been found only in Queensland, far to the north. The paucity of large polar dinosaurs may reflect a real absence or merely the selective preservation of small bones. Peter Trusler painted the mural of the creatures, which was created for an Australia Post stamp issue entitled “Australia's Dinosaur Era.”

1. LEAELLYNASAURA

2. AUSTRALOVENATOR

3. MUTTABURRASAURUS

4. PTEROSAUR (FLYING)

5. ANKYLOSAUR

6. ATLASCOPCOSAURUS

7. ORNITHOMIMOSAUR


Peter Trusler

In the Early Cretaceous period, just over 100 million years ago, Australia lay alongside Antarctica, which straddled the South Pole as it does today. Australia's southeastern corner, now the state of Victoria, lay well inside the Antarctic Circle. At that time, the region hosted an assemblage of animals and plants that lived under climate conditions having no modern analogue. The average temperature appears to have ranged from frigid to low temperate. Through the long winter, the sun did not shine for weeks or months at a time.

Many dinosaur lineages survived in this strange environment after they had died out in other places. At least one member of the group evolved an adaptation to the cold and to the dark that is interesting both in itself and for what it tells of the passing of a biological epoch. If global cooling indeed killed the dinosaurs, as many paleontologists have suggested, then Australia's species were the ones most likely to have survived the longest. Did their adaptations to an already marginal climate help them survive a sharp cooling trend, one that caught species living on other continents unprepared?

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