by Tim Flannery
When he turned up later that day, Tom told us that after we upped stakes he heard a wheezing old truck bump along the track to the quarry—the first visitor at the remote location. As the battered vehicle drew near it slowed to a halt and its driver, a rabbit shooter who sat propped between his rifle and a slab of Victoria Bitter, stared at Tom, who had entirely forgotten the strangeness of his habiliments, and asked in a tremulous voice, ‘What are you doin’ out here, mate?’ The thunder pealed and the first fat drops of rain began to fall as the swaddled figure, without car, horse or even camel to support him, replied in a broad American accent, ‘I’m digging for turtles.’ At this the rabbiter gulped, turned mechanically away, and drove on up the track.
Back at camp we were sure that we were in for a soaking. I wandered
Tom Rich, enveloped inthobe and gutra, levers basalt blocks from the fossil soil horizon at Hamilton, Victoria, in the late 1970s.
out among the dry cane-grass on a sand-dune, where between thunderclaps I heard something deep underground. It was the unmistakable croaking of frogs, yet below the surface the sand was still as dry as a mummy’s handshake. That afternoon the heavens opened and we copped four centimetres of rain in a couple of hours. I poked my head out of my tent in the fading light to discover that we were now camped in an inland sea populated with thousands of frogs. Their croaking was deafening, for they were everywhere. I wanted a close look, so I placed three in a billy that I hung from a coolibah, there to await inspection by the light of day.
The raucous croaking made it almost impossible to sleep, but about midnight a distinct shift in the sound occurred. Earlier it had come from all around, but now it was distinctly louder just north of my tent. The frogs were concentrating in one spot, and by morning all croaks—except for the three amplified ones coming from my billy—emanated from the one place. Beyond the camp the water still lay in a broad sheet, so I had no idea what brought the frogs together. In a few days, however, their strategy became clear. As the water receded, one pool after another dried up until there was only one left—exactly where the frogs had migrated that first night. Just what prescience led them to the spot is still a mystery to me. The next morning I discovered that my three captives were pale, flabby, golfball-sized creatures, bright of eye and with a determined turn to their wide mouths. I later identified them as water-holding frogs (Cyclorana platycephalus). They are among the hardiest of all amphibians and live buried in a state of suspended animation for years in the salty inland deserts, then emerge during a wet to feed and reproduce before the diminishing puddles drain away into the sand.
10
The Oldest Kangaroo
That expedition was cut short by the rain, which made the country impassable. Despite this I did locate some fossils from Lake Tarkarooloo in the Museum of Victoria’s collection—they had been under my nose all the time. Although they were just a few teeth and foot-bones, it was clear they once belonged to animals similar to rat-kangaroos. By Lake Tarkarooloo times kangaroos were well on the way to becoming kangaroos as we know them, so I would have to search elsewhere to find the ‘missing link’ of kangaroo evolution—a species between the kangaroos and their possum-like ancestors.
The chance to do just that came a few months later via a visit from a famous American palaeontologist to whom Tom wished to show the outback. Lake Pinpa, a few tens of kilometres east of Lake Tarkarooloo, was to be our destination. I had seen ‘Dinosaur’ Jim Jensen before, and like Sandy McTaggart, in a National Geographic magazine. A full-page photo was dedicated to Jim as he lay stretched out beside the limb-bone of the largest dinosaur ever discovered. Yet it was only when I took in all six feet four of Dinosaur Jim and shook his hand that I realised how big that bone really was. Tom had confided that Jim was a good Mormon, and I anticipated having to stay on my best behaviour. Jim, however, bore little resemblance to the suit-wearing brethren who beat a path to my family home. As we sat around the campfire on that first evening I commented on the scattering of mosquitoes that buzzed about, the last recruits perhaps, of the big rains. They were nothing, Jim asserted, compared with what he had endured in Alaska. There, he said, the mosquitoes were so big they ‘could stand flat-footed and fuck a fowl’.
Jim’s experience of fossil hunting the world over was completely awe-inspiring. He had visited every continent in search of fossils and had worked with such legendary figures as Alfred Romer and George Gaylord Simpson. He had even prepared for display Australia’s most famous fossil—the skeleton of the whale-sized marine reptile Kronosaurus. It had been discovered in the 1930s in Queensland, and now has pride of place in Harvard’s natural history museum. To protect it during transportation, the huge specimen had been packed in wool scraps—dags mostly—and when it arrived in Boston harbour, in summer, it stunk so high that it had almost been destroyed as a risk to public health. I learned a huge amount from Jim about how to find and clean fossils, but it was his gift of a first-hand history of my science that has stuck most strongly with me.
Despite the fact that recent rains had washed out gullies around the lakes, exposing fresh sediment, fossils of land animals again proved hard to find. We concentrated our search on Lake Pinpa. The prettiest lake in the whole region—a mere football field of salt in comparison with most—its name derives from the Aboriginal word for the Callitris pines that grow in gullies along its western shore. Such bright green trees are rare in this part of the desert. Below them, low on the shore, is a layer of sediment almost as green in hue, and it is this which attracted us, for the combination of the fossils it had yielded and its stratigraphic position suggested that those clays were the oldest mammal-bearing rocks from the age of mammals then known on mainland Australia—perhaps as much as 40 million years old.
We rose each morning to cook breakfast, then commenced crawling—and I do mean crawling—over those green clays, examining every speck of colour in the hope of turning up the bone of an early marsupial. For days we shuffled on all fours, carrying our caravan of flies as we searched for the tiniest clues of past life. As in most of the Frome Basin sediments the bones of aquatic creatures—turtles, fish and lungfish—were abundant. Even the skeleton of a long-vanished freshwater dolphin had been found there. But the remains of land-based life were rarer—perhaps a thousand times rarer—so much crawling was required before a single such fossil was found. We discovered that, strangely, the bones of land animals were often found associated with a whitish stain. We had no idea of its origin, but scientists have since suggested that it is the last remnant of decomposed crocodile faeces, voided far from shore by the marsupial-eating reptiles.
A few years earlier Tom had discovered a small tooth at Lake Pinpa which resembled the serrated premolar of a primitive kangaroo. Several kinds of marsupials, both living and extinct, possess such teeth, so we needed additional fossils—preferably bones from the hind-limb or an entire jaw of this elusive (and still unnamed) creature, to identify it—and if from a kangaroo, decide whether at this early stage in their evolution the ancestors of the living kangaroos hopped or not.
Hopping entails considerable risk of mishap, for it creates such enormous stresses that hind-limbs have to be modified in extreme ways to minimise breaks and dislocations. The pelvis and ankle are particularly vulnerable, for this is where the stresses become most extreme. In the marsupial kangaroos, the two sides of the pelvis are strongly welded together, a solution not readily adopted by placental mammals, which must give birth to large infants and so need flexibility in the pelvis. This may explain, in part, why hopping has not evolved among the larger placentals. And, as we have seen, the kangaroo ankle is highly modified to allow movement in only one direction—the slightest sideways slip and you’d have a crippled kangaroo.
Searching for such rare fossil bones in the Australian desert may seem a hopeless task. Maybe it is, and perhaps I was just extraordinarily lucky, but after several days of crawling around on the salty margin of Lake Pinpa my eyes lit upon a tiny square of bone. No more tha
n three millimetres on each side, it was about the size of a match-head. As was my habit upon coming across such minute treasures, I sucked the dirt and salt from it, for the tongue is a far more delicate manipulator than the hand could ever be. When I carefully removed it from my mouth, glistening and clean (and thus moistened, less likely to roll away), I could see tiny square facets on it, including the distinctive stepped facet that helps make the kangaroo ankle so stable, and which is unique to them.
Here was the ankle-bone of a kangaroo unlike any I had ever seen, and I had studied quite a few. What made it special, apart from its tiny size, was the joint in front of the stepped one—the one where the bones of the foot articulate with the ankle. Instead of being oriented straight across the foot (and thus creating a stable platform), it sloped at an angle, much like the facet does in a possum. Had I found the missing link between kangaroos and possums? This we cannot tell without more evidence, but I was certain of one thing: the rat-sized creature that owned it may have been able to bound, but its sloped foot-joint could never bear the stress of hopping.
It is a strange thing to crawl for days on end along the edge of a salt lake in one of the most empty deserts in the world, your eyes strained with the glare of the sun and the effort of concentration, your back a vast, slow-moving vessel crewed by a thousand flies. But it is even stranger to pluck a speck of ancient bone from a decomposed crocodile turd, apply it to your tongue, peer at it, then rise to your feet screaming in exhilaration. Yet that is what happened the day I found the bone of the grandfather of all kangaroos.
When trying to imagine what kind of creature possessed that ankle-bone, we can be guided by a tiny, still-living inhabitant of the north Queensland rainforests. The musky rat-kangaroo is more rat in appearance than kangaroo, and at only half a kilo it is just twice the size of a house rat. It scuttles about the rainforest floor in broad daylight in search of insects and fallen fruit, and is the only kangaroo to do so. But to examine its peculiar anatomy you need to have one in hand. Close up, its tail is about as thick and long as a pencil and covered in coarse scales. The tail is held straight out as it scampers about and plays no role in locomotion. On its foot you will see a grasping first toe, similar to that of possums. It helps the musky rat-kangaroo scramble over fallen logs and up inclining tree-trunks. But no matter how long you observe one, you will never see the musky rat-kangaroo hop, for it is the only living kangaroo incapable of doing so, and must instead get about on all fours by bunny-hopping.
Despite the gratifying insights that the musky rat-kangaroo can bring to the study of ancient bones, that earliest kangaroo fossil remains as much a frustration as a source of enlightenment, for to this day we have no idea how long ago it lived. Over the past quarter-century there has been plenty of arm-waving, guessing and tenuous reasoning to support a view that it might be around 25 million years old, but it could be 40 million, or as little as 20 million years old. Our incapacity to date the fossil-bearing sediments directly holds true for all but one of the mammal-bearing fossil deposits found on mainland Australia older than five million years, and until we have a way of answering the ‘when’ of palaeontology we will be unable to adequately address the more interesting ‘why’ and ‘how’.
We can, nevertheless, say a little about the vanished Australia that was home to this miniature kangaroo. We know from other fossils discovered at Lake Pinpa that at the time the roo lived the Frome Basin was a vast, freshwater lake which must have had some connection with the sea, for long-beaked freshwater dolphins descended of seagoing ancestors abounded in its waters. Fish, crocodiles and tortoises also shared the lake with an astonishing nine species of lungfish, the largest of which reached three metres in length. There were ancient, toothed platypuses, grebe-like birds, pelicans, shags and ducks, all species now long extinct, while curlews, songbirds and gulls populated its shores. A touch of the exotic was added by flamingoes. And there were tortoises, resembling those of the Galapagos but with armoured tails and cowlike horns on their head, grazing beside that ancient lake.
The marsupials were, by and large, unlike anything living today. The largest were sheep- to tapir-sized creatures known as wynyardiids and ilariids. The first takes its name from the sleepy town of Wynyard on Tasmania’s north coast, whose scientific claim to fame is a rocky outcrop near the town’s golf course where in the late nineteenth century the skeleton of a brushtail-possum-sized animal was found. Named Wynyardia bassiana, the skull and jaw had been so exposed to the waves of Bass Strait that every tooth had been eroded away, but the bones were found in sediments that yield tiny marine organisms, allowing us to date this particular skeleton to around 23 million years old. Frustratingly, however, not one more scrap of land mammal bone has been found at the outcrop since.
The ilariids’ name is from an Aboriginal word meaning ‘strange’, and a highly appropriate name it is, for with no close living relatives these primitive herbivores (represented by several species) may have resembled ponderous terrestrial koalas. Odd-looking Miralina and Ektopodon possums were also present. Around the size of a brushtail possum, Ektopodon was as short-faced as a cat and probably a fruit-eater.
Ringtail possums, a strange pygmy possum, an ancient koala and our miniature, ancestral kangaroo complete the rollcall of the marsupials of that vanished era. We know almost nothing of the vegetation that fed these creatures, though we can surmise that the Flinders Ranges supported hanging bowers of verdant rainforest. On the plains around the lake a mixture of herb-filled glades and gallery rainforest may have grown. To admit the slenderness of our knowledge of this vital period in Australia’s prehistory is painful for one who has spent a lifetime studying fossils, but I must concede that it will fall to future generations to see the details of this age with true clarity.
11
Skeletons in the Dead Centre
A region of sand dunes and expansive salt lakes lies at the heart of Australia. Lake Eyre, the largest of them all, extends 200 kilometres from north to south and sixty-five east to west—the size of a small European country. While the lake itself has yielded few fossil deposits, smaller nearby lakes hide a fantastic wealth of materials, a bounty which has drawn me back repeatedly since my first visit in 1980.
The region is best approached by driving north from Adelaide on a road that passes west of the Flinders Ranges, their sublime peaks rising like ramparts out of the desert plain. In the middle of this grand landscape lies Parachilna, an old stop on the now disused rail-line to Marree. The settlement has recently found a second life as a stopover for tourists who can enjoy a camel-and-emu sausage or kangaroo steak before retiring to the comfort of clean sheets. As we pulled into Parachilna on a visit in 1997 a sign caught my eye. Written with texta on a piece of cardboard propped beside a humpy, it read ‘Kev’s Camel Capers’. A few camels hobbled in the distance and a man, the presumed master of the ‘capers’, lay prone in the dust under a low bough shelter. One of our team introduced himself and asked how business was going. ‘Better than the dole’ was Kev’s reply. He then explained that he got his animals from a camel butcher who caught them up around Lake Eyre. Asked if he had any plans, Kev responded, ‘Yeah. Got a Filipino bride coming out next month. Got her in Manila. Advertised that I ran a transport business.’ And, from what I heard at Parachilna, she would not be the only Filipina to have moved to the outback.
After a camel sausage we headed to Marree, the only town in the salt and gibber country east of Lake Eyre. I was hoping to meet Old Achmed, the last of the Afghan cameleers, those hardy frontiersmen who provided transport for explorers such as Warburton and Giles, and who for almost a century supplied remote settlements with goods and news of the outside world.
Marree is little more than a hotel, a store, and a motley collection of buildings clustered around the disused railhead. I found Achmed in the ‘coffee shop’ (which was also the general store, petrol station and anything else it needed to be). He was full-faced, had a rounded figure and seemed to be a youthful eighty-som
ething—hardly what I had expected.
Achmed told me that until 1956 he had worked with his father carting beer on camel-back from the railhead at Marree to the Birdsville pub—a distance of about 450 kilometres—and being good Muslims they were probably the only people in the outback you could trust with the precious cargo. It was an incredibly tough life, the two-week journey crossing a region along the edge of the Simpson Desert treacherous to negotiate. Then, in 1956, a truck started to make the run and put the cameleers out of business. Achmed was forty-two years old, and for the first time in his life found himself out of work.
On hearing his story I made sympathetic noises, imagining the difficulties he faced in retraining, but Achmed would have none of it. ‘No, mate,’ he expostulated, ‘it was the happiest day of me life.’
‘But how did you make up the income?’ I asked.
‘Oh, Dad never paid me, so there wasn’t much difference, except for the work.’
The community at Marree is mixed—Aboriginal, Afghan and European—and from the pub I saw a couple of Aboriginal youths, golf clubs slung over their shoulders, heading for a graveyard of old cars. When I asked the publican what they were doing he looked at me as if I were an idiot and spelled out slowly, ‘They’re going to play a round of golf, mate.’
‘But where’s the course?’ I replied, looking out on the bulldust and rusting metal.
