Discovering the dinosaurs Down Under
From killers of the freezing Antarctic wastes to titanic herbivores, Australian dinos are being dug up in great numbers.
I WAS FLAT ON my stomach in the dirt, feet in the air, when I heard dig leader David Elliott yell: "Don't you bloody well find anything else down there." But I had.
It was August 2007, we'd been digging for two weeks and this was the last bone to come out of the ground. It was a gastralia from a carnivorous dinosaur. The small floating rib looked more like a chopstick than a piece of prehistoric giant. We'd run out of plaster and hessian - the first line of defence against the atmosphere from which bones have been safe for millennia - and had to get off the property before shearing began. So, I climbed out of the hole and carefully wrapped the fragile piece in paper and foil.
On my first dig in Winton, Queensland, five years earlier, we'd been excited by any tiny, weathered bone fragment we found, and diligently collected and mapped each one in the hope that it might lead to a larger trove below. I volunteered to dig again each year after that, but without much success. Our luck started to change in 2006, though, when the owner of the property on which we were digging came to visit and mentioned another site she knew. I was with Queensland Museum palaeontologists Dr Scott Hocknull and Dr Alex Cook when she showed them the site that yielded 'Matilda' - Australia's most complete species of sauropod from the Cretaceous. "I don't think we really ever thought that something so well preserved could be hidden underneath the black soil," Scott says.
Nothing moves quickly in central Queensland, especially in the world of palaeontology. It took three more years of digs and two years of preparation work before those bones were presented in June 2009 as Diamantinasaurus matildae, a herbivorous giant of a sauropod 16 m long and 3 m tall at the hip. But perhaps most astonishing was what lay beneath Matilda. After her huge bones were removed, the smaller, elegant remains of a hitherto unknown theropod were found tucked safely below. 'Banjo' (Australovenator wintonensis), with his 30-cm-long claws and flesh-slicing teeth, stole the spotlight and is Australia's most complete carnivorous dinosaur. "We were used to big sauropod bones by now, but the discovery of another very different dinosaur from the site blew me away," Scott says. "Australia's dinosaur world was right there under our noses all along."
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Otway Ranges: fossil hunting
Australia's fossil beds are in some of the most inhospitable and remote regions of the nation: from the daunting Otway Ranges of Victoria's southern tip, to the underground opal mines of Lightning Ridge in north-west NSW and the blacksoil plains of central Queensland. And the usual rules of palaeontology don't seem to apply in Australia. The best fossils overseas are found in geological layers that have been folded or eroded over millennia to display vertical beds from which the fossils protrude like some new-age artwork.
Australia's ancient landscape has undergone little movement; the layers of time have remained mostly horizontal, exposed only by harsh weathering. It's thought that, in the rest of the world, only about one third of all dinosaur species that existed have been discovered. Down Under, we're likely to have found far fewer than that.
David Pickering is collection manager of Museum Victoria's (MV) fossil vertebrates and plants. He pulls out drawer after drawer in the climate-controlled warehouse to show me hundreds of boxes, each with a bone from ornithopods and ankylosaurs, and tiny little vials with theropod teeth. Their serrated edges are still sharp, after 100 million years in the earth.
The museum holds an astonishingly varied range of species, including the remains of small herbivorous Victorian ornithopods with tongue-twister names such as Fulgurotherium and Atlascopcosaurus. Many were discovered by palaeontologist Dr Tom Rich, a team of volunteers and his wife and colleague Professor Pat Vickers-Rich of Monash University, during the past three decades, and prepared lovingly by David and Lesley Kool at MV. Size isn't everything. One of the most prized possessions in the Victorian collection is the skull of Leaellynasaura, a tiny herbivore with giant eyes and optic lobes - thought to be a physical adaptation to the dim light in their cold, forested polar environment.
During the time of the dinosaurs, Australia was part of Gondwana, and its coastline stretched from subtropical zones in the north to polar latitudes in what is now Victoria. Another species, Timimus, is thought to be a small ornithomimid (or "bird mimic"), and these ostrich-sized, long-legged dinosaurs were some of the fastest runners of all. The species was described from a single thigh bone.
The work of Tom, Pat and their team has more than doubled the tally of Australian dinosaur species. Together they have named many of Australia's dinosaurs, including Timimus and Leaellynasaura - named after Tom and Pat's son and daughter. But the identity of many bones remains a mystery. The 2010 announcement in the journal Science of an as-yet-unnamed tyrannosauroid - a tyrannosaur-like dinosaur - has caused the most recent excitement. (See the illustration). Though more recently, this has been disputed.
It was described from a single hip bone first discovered in 1989 and safely stored in MV's drawers for two decades. One-third the size of T. rex and 40 million years older, this carnivore is the first tyrannosauroid known from the Southern Hemisphere, and shows these animals were much more widespread than first thought. Australia's tyrannosauroid possibly had feathers, as did other members of the group.
The bones of Timimus show some evidence of hibernation, another coping mechanism for polar conditions - and another clue about where to start looking for more dinosaurs. In fact, a 2005 discovery in the US suggested we might have been looking in the wrong places. Tony Martin, an animal-tracking expert at Emory University, in Georgia, discovered small ornithopods in Montana in what appear to be prehistoric burrows. An adult and two juveniles of the species Oryctodromeus cubicularis ("running digger of the lair") were found together in the 95-million-year-old den. Tony's research opens a new prehistoric possibilities, and on a trip to Australia last year he identified two possible burrows on Victoria's coast.
Ready for battle. Minmi, a formidably armoured species, is Australia's most complete dinosaur.
With bony plates lining its back, this 1-m-tall ankylosaur was well equipped to defend itself against the predators
of its time in Gondwanan Australia. Minmi's remains have been found in both Victoria and Queensland.
(Image: Xing Lida)
It's a beautiful morning looking out towards Bass Strait, although the sun is yet to climb above the horizon. I've taken the winding coast road to the Bunurong Marine Park, near Inverloch on the southern Victoria coast, which is home to a 17-year-old fossil site dubbed Dinosaur Dreaming. Each summer, a motley and enthusiastic team of volunteers convene here to search for the dinosaurs that trod the icy forests of southern Gondwana more than 110 million years ago (mya). And every day they race against time. As the tide falls, the palaeontological chain gang begin the painstaking task of cracking open rocks. Each piece is cut down to the size of a sugar cube and carefully probed for hints of bone.
Before midday the water starts to slowly creep back towards the shore, encroaching on the dig site. I notice a trickle snaking down into the pit, just as someone discovers something. The pace suddenly picks up - now it's a battle against the tide. The volunteers are ankle-deep in water, but the bone - possibly a piece of armour from a plant-eating ankylosaur - is stuck too deep to be easily removed. Even sandbags can't stop the tide and after all that careful work, the decision is made to rebury and protect the bone before sand and seawater swallow it once more. The sea is both friend and foe, making the site difficult to access but, at the same time, protecting it from fossil thieves.
"It's persistence," says Tom Rich of dinosaur hunting. "Both luck and persistence; that's what pay off in this business." Tom first took up the quest in 1978. His mission was to find ancient mammals, species that might help to fill the gaps in Australia's largely unique marsupial record.
"The thing about Australian dinosaurs is that we haven't found the dinosaur equivalent of a koala," Tom tells me, his American accent still strong. "There're no dinosaurs recognised so far in Australia that are really distinct to the known dinosaur families in the world."
The most significant discovery recently is Sinosauropteryx prima, the first known feathered species. Found in Liaoning Province, China, in 1996, it was the definitive evidence that birds descended from dinosaurs. Similarities between dinosaurs and birds have long been noted. Both have a characteristic wishbone and hollow bones. Archaeopteryx, a primitive bird with a bony tail and teeth, was key evidence in early evolutionary debates after its discovery in 1861. It's now commonly believed that many dinosaurs had downy coverings or even fully developed flight feathers. Tom sees similarities between the deposits of Koonwarra, Victoria, and those in Liaoning, which are of similar age. About six feather fossils have been found at Koonwarra. "The rocks in the [Liaoning] site look so much like the stuff at Koonwarra," Tom says. "It's a fairly unusual thing to do - to preserve a feather - and Koonwarra does that."
The problem is getting to the proof. "The most interesting dinosaurs are not all that common in [Liaoning] - but the reason they get them is because they clear an awful lot of real estate," says Tom, who estimates that more than 50 sq. m of solid rock needs to be removed in Koonwarra before anything of note is found. Only 20 per cent has been shifted so far.
Tom's plan for the next few years is to scour the coastline of Victoria and map any occurrences of what may be burrows. "We're trying to find a place where there're burrows exposed, so we can get at them. The idea would be to dig a few of them out and see if you've got any bones in them," Tom says.Unfortunately, the two possible burrows that Tony Martin identified are in a place that would make excavating a tunnel to China look easy.
In 1978, university students and cousins John Long and Tim Flannery travelled to Eagles Nest, Victoria, to hunt dinosaurs. Australia's first dinosaur fossil - the Cape Paterson Claw - had been found there in 1903 by William Ferguson, a geologist with the Mines Department of Victoria, who was following the coal seams that thread the region.
"I'd been collecting fossils since I was seven, but I'd always wanted to find a dinosaur," says John, who has studied Australian palaeontology for more than three decades and is based at the Natural History Museum of Los Angeles County, in California, USA. "We scrambled down the cliff; it was a grey, rainy sort of a day, and within about five minutes of getting to the beach I'd picked up a rock that had a bone running through it...a dinosaur bone." Soon after, they returned to the area and found another rock, which held the femur of a small herbivorous ornithopod, and was the catalyst for the sustained hunt for dinosaurs in Victoria that continues today.
The majority of Australian species of dinosaur are described from just a single bone. In some cases, even well-researched bones are giving up new information. "With increasing technology we can go back to old fossils and get more of their secrets out of them," says John. "And that's been the success of our last five years of research with Devonian fish. We've even been able to go back to specimens we described 20 years ago and find things out about them that we never dreamt of. It's an exciting time for Australian palaeontology. [Matilda and Banjo] were the first big discoveries in about 30 years in Australia to really rock the boat."
More momentous finds are not only possible but likely, according to John. "For those looking, there are whole mountains in Western Australia that are Cretaceous and are of the right rock types to find dinosaurs in them," he says. "The other rocks in that Kimberley region of the right age have also produced fossil vertebrates of the Triassic, so we know that it's just the right setting to find dinosaurs, but it's just so hard to get out there ... I reckon that's where the really big discoveries will be made one day."
On my first dig I found nothing except a handful of blisters, but I was hooked. Across Australia those bones are there, waiting for someone with the right combination of curiosity, determination and ingenuity to mark "X" and start digging, continuing the search for Australia's dinosaur dreaming and the chance to write more prehistory.
Source: Australian Geographic, issue 99 (July - September, 2010
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