New dinosaur tracks from Australia reveal that large, carnivorous theropods, giants who trod on the polar regions during the Early Cretaceous, leaving only their footprints behind, are now known to have existed in these harsh environments.
Uncovering Polar Predators
Researchers, led by paleontologist Anthony Martin of Emory University, have found an incredible site at the Wonthaggi Formation in southern Australia. Large theropod carnivorous dinosaurs, which included Allosaurus and the later Tyrannosaurus rex (something like Jurassic Park’s Velociraptor), prospered in this polar environment up to the time when Australia and Antarctica finally became separate.
The trove contains 18 tracks from theropods, the group of carnivorous saurischian dinosaurs that included the later T. rex and other tyrannosaurs, and four tracks from smaller ornithopods, a group of bipedal plant-eaters. The biggest theropod track is a mighty 18.5 inches long, corresponding to over six feet high at the hip for these top predators. These latest findings provide the best evidence yet that such giant carnivorous dinosaurs existed in these former polar lands, and some of those will have depended on smaller dinosaurs, fish and turtles to survive from year to year.
Surviving the Polar Winters
The southern Australian Wonthaggi Formation provides a rare insight into the Early Cretaceous palaeo environment. During that time the area was a rift valley with braided rivers and had freezing conditions with months of darkness during the polar winter.
Somehow, the placental large theropod dinosaurs managed to survive and adapt through these extreme conditions. The variety of track sizes hinted to the scientists that these predators could have been nesting and rearing their young in the region, able to thrive into the summer months when prey was plentiful.
Highlighting the significance of these finds, is that most of records in Wonthaggi Formation were previously based on isolated small bone and teeth fragments, which may have been washed there by flood events. On the other hand, the tracks show that a variety of dinosaurs did indeed call this polar environs at least for some time.
Conclusion
The finding of these substantial theropod tracks from a locality within the Wonthaggi Formation of southern Australia, raises question with regards to how we understand ancient biotas in highest latitudes. It proves these apex predators survived and were able to accommodate the challenging conditions, a clue that gives an eye into the resilience and variety of Early Cretaceous era dinosaur ecosystems. We will only learn more about these ancient polar environments and the organisms that lived there as researchers find additional evidence at this site.
