Who wielded the Otway Claw?
Meet Victoria’s top Cretaceous predator—a dinosaur that would have eaten Velociraptor for breakfast.
The hunt is on to discover the identity of a fast-running, predatory dinosaur which once stalked the polar forests of what is now southern Australia.
It comes after a fossilised claw was found in the sandstone off Cape Otway on Victoria’s Shipwreck Coast.
Those intervening five years were spent analysing the find and unearthing more remains at the site—known as Eric the Red West—the nature of which made for a particularly tricky piece of detective work.
Say, for example, a dinosaur drowns and its body washes into a quiet billabong. Millions of years later, a palaeontologist digs up that now-fossilised skeleton, largely intact. With relative ease, that palaeontologist can say how large the dinosaur was, whether it belonged to a known species, etc.
Eric the Red was no billabong. Instead, it was a log-jam in a fast-flowing river, and the claw in question caught amid a jumble of other bones, including turtle, before being covered in sediment and fossilised.
The case of the Otway Claw would take some, ahem, serious digging.
Using ancient pollen and spores also found in the sandstone rock, the team from Museums Victoria and Swinburne and Monash universities were able to date the find to about 110 million years. Meaning whoever wielded the claw was doing so in a rift valley between modern-day Australia and Antarctica during the Early Cretaceous.
After establishing the scene and time-frame, the researchers ran their evidence through a database of suspects.
Comparing it to other fossil discoveries, they determined the claw belonged to a theropod, a clade—or branch on the evolutionary tree—of dinosaurs whose ranks include Tyrannosaurus and Velociraptor.
Moving further down the tree, the researchers were able to place the claw among the megaraptors—a clade of hunters which thrived in what is now South America and Australia.
Furthermore, that is was highly likely to fall within the genus Australovenator.
Within Australovenator is a single known species, wintonensis, first described and named in 2009 for the outback Queensland town near which it was found.
More than 1.5-metres tall, about six-metres long and up to 1000-kilograms heavy, Australovenator wintonensis was a fast and agile hunter.
The largest known Australian theropod, it would likely have been the apex predator in the land that is now Victoria.
So with this match, case solved? Perhaps, but then again, perhaps not.
The problem with drawing a perfect comparison between the Otway Claw and the species found near Winton is that the former is about 15-million-years older and was found several thousand-kilometres further south than the latter.
Museums Victoria palaeontologist Tim Ziegler says that time and distance poses two likely hypotheses—both of which are equally intriguing.
On one hand, the remains could indeed both belong to same species. Under this scenario, Australovenator wintonensis roamed huge swathes of Australia over millions of years and hunted vastly different prey.
In Queensland, A. wintonensis is believed to have fed upon sauropods. But these huge, slow-moving and long-necked herbivores are not known to have inhabited Victoria.
Here, a top order predator would have hunted upon ornithopods, small two-legged dinosaurs often around the size of a brush-turkey. It’s against this prey that the Otway Claw makes sense—each of Australovenator's muscled arms would have been topped with three flexible claws that snapped shut like a spring-loaded trap upon its fast-moving prey, Tim says.
Then there is hypothesis number two, a scenario in which the Otway Claw belongs to a predecessor of A. wintonensis—an as yet unknown species within the Australovenator genus. Which, Tim says, is more probable.
‘Based on the rate at which these animals go extinct and evolve, it’s unlikely that the Otway Claw would have belonged to the same species as that found in Queensland,’ he says.
‘Though it would have belonged to a close relative.
'We don’t have sufficient scientific material to create a new species—yet.’
Tim Ziegler, palaeontologist
Which dangles the tantalising prospect that the Otway Claw could be a vital piece in puzzling together a new, Cretaceous-period, apex predator.
Either way, more bones will need to be unearthed and more research done to provide a definitive answer.
That work is set to continue with a major excavation at Eric the Red planned for 2020, after a positive test dig in November.
As those results start revealing the story of the lost world of East Gondwana, we often grope for comparisons to dinosaurs made familiar by Hollywood. And so, the mysterious predator who wielded the Otway Claw is sometimes billed as Australia’s Velociraptor.
But, as Tim says, that’s a particularly unfair comparison. In reality, the villains of Jurassic Park were about as large as a turkey and, therefore, a similar size to the plant-eating ornithopods of Victoria.
Read the scientific paper describing the Otway Claw and several other fossils found at Cape Otway here: