On a fine March morning, while staff at Melbourne Museum put the finishing touches on its blockbuster exhibition Jurassic World, eminent palaeontologist Dr Thomas Rich, 74, grey haired and bearded, strides to the Royal Exhibition Building next door. In his faded beige shirt, breast pocket bulging with a magnifying glass and notebook, he looks as if he’s just come from a dig. Opening an inconspicuous door, he steps down into the bluestone basement, where the museum’s collection of dinosaur bones is currently stored.

“It astounds me,” Rich says, settling into a chair in his windowless office, “that I can walk down the street and talk to people at random, and they have no idea that dinosaurs are known from this state and that they were polar.”

Indeed, the work of Rich and his equally distinguished wife, palaeontologist Patricia Vickers-Rich, has proved that during the Cretaceous period, a mere 65 to 145 million years ago, when southern Australia was still connected to Antarctica, polar dinosaurs lived in what is now Victoria. With extended darkness for much of the year, the dinosaurs battled it out in icy winter temperatures that potentially dipped to -32 °C. The American-born Riches have also been working a tough patch. Australia’s geology makes dinosaur hunting a difficult day job. But, as the National Geographic Society puts it, the Riches’ “tireless and virtually superhuman efforts to gather and interpret fossils of great significance” have “completely revised our understanding of Mesozoic life at high latitudes”.

For more than 30 years the Riches have been leading digs around coastal Victoria, uncovering much of its dinosaur heritage, plus information on the mammals and birds living in the prehistoric shadows. Despite the public fascination with dinosaurs, these digs tend to run on a minuscule budget and are manned by volunteers. “You have Spielberg and all these people making lots of money [from stories about palaeontology] and we don’t get much of it,” Rich concedes. Nevertheless, in February the Riches supervised another three-week dig at a remote site on the Otway coast, 200 kilometres south-west of Melbourne. “A large carnivorous dinosaur is turning up,” Rich mentions casually. “We got a claw in 2014 that’s about this long.” He indicates 15 centimetres. “And this year we found a number of larger bones nearby, but they’re scattered.”

Rich thinks they may be the assorted vertebrae, rib, gastralia, limb and skull fragments of an Australovenator, previously known from a partial skeleton found in Queensland. The recent dig also uncovered three lower jaws, one or more of which might have belonged to one of the Riches’ discoveries, the herbivorous dinosaur Atlascopcosaurus. (Some of these bones are now across the road from the museum at St Vincent’s Hospital. When the radiographers aren’t too busy, they run the new discoveries through the CT scanner to help Rich analyse them.)

Rich’s office is filled with curios from outer space as well as from deep underground. There are globes of Mercury, Mars, Venus and the Moon, a box of “crummy” dinosaur bones (“probably a sauropod from Queensland”) that he dispenses to children and visiting writers, and artistic renderings of what the dinosaurs he’s discovered might have looked like. There is also a stockpile of tinned chicken soup for lunch, and a range of visual aids to help Rich, whose eyesight is failing, analyse fossils.

On his wall is a framed portrait of Leaellynasaura amicagraphica, a dinosaur named for the Riches’ daughter, Leaellyn, who as a toddler asked her father for her own dinosaur. The picture is based on a specimen Rich found that had no signs of predation, and the Leaellynasaura is shown, moments after death, sprawled by the side of a billabong, palaeobotanics reflected in the water. Somehow it brings to mind the painting Ophelia by Pre-Raphaelite John Everett Millais. It looks as if the dinosaur has just died from a broken heart … So, what does Rich think happened?

“I don’t know!” he cries. “I have a brother-in-law who’s a physician, and he says half the time when they do autopsies the person should still be alive as far as they can tell! So, after 106 million years, it’s hard to say.

“Anyway, I’ll show you our fabulous dinosaur collection.” He rises, adding, “You’ll be underwhelmed.”

In the hallway outside his office there stands the first of a series of vintage grey and green cabinets that hold minerals and fossils. In a few weeks’ time the collection will be packed with foam and bubble wrap for its move 100 metres next door to Melbourne Museum. The Exhibition Building’s basement is being “refurbished with a kitchen for lush banquets upstairs,” Rich explains, “and we’re being kicked out.”

From the cabinet he carefully takes a plastic tray, which is filled with the lower jawbones of prehistoric mammals. Some, resembling miniature shrews, could have weighed as little as 2 grams. In a piece of shale the size of a child’s fingernail, he points out a row of tiny teeth.

“I’m sorry,” he says, “this is the best we can do.”

Rich is right: the jaws are not show-stealers.

“One hundred and thirty million years, roughly.” He answers the question of their age just before it’s asked. “Give or take a couple of weeks.” A pause. “Birthday candles?”

We move down the basement’s hallway, and when Rich stops to open another cabinet, he says, “This is the result of 35 years of effort [and] it’s not as though these cases are jam-packed.” He takes out drawers holding small fossils and bones that relate to around 20 prehistoric animals found in Victoria, including mammals, dinosaurs, amphibians and birds.

“If you were working in Montana or Mongolia, you’d be judged incompetent if you only got that much stuff. But if you want polar dinosaurs from Australia, you can’t dig in Montana or Mongolia; the Victorian coast is the place to go.

“The potential for finding other stuff is there, but we’re not going to find the Big Badlands of the Dakotas, we’re not going to find the Gran Barranca of Patagonia, where you have this 700-metre sequence and just walk up and collect fossils. That ain’t going to happen. Geologically, we know this continent too well. It will be a tiny spot.”

Rich opens one last cabinet and looks for the museum’s feather fossils, discovered at what was once a polar lake near Koonwarra, 150 kilometres south-east of Melbourne. When the feathers were found on a dig in the 1960s, they were believed to have come from prehistoric birds. The discovery of fossils in Liaoning, north-eastern China, proving there were feathered dinosaurs, has, however, prompted Rich to reassess the fossils in his collection. Last year an international expert identified at least one of the Koonwarra feathers as belonging to a “non-avian” dinosaur.

Rich believes that the conditions at the Koonwarra site are analogous to those at Liaoning, and that there’s a chance of finding skeletal evidence of feathered dinosaurs here, too. If he can secure the funding, he wants to reconstruct the history of a polar lake from the time it was formed to its extinction, 5000 to 10,000 years later. “I suspect if we could detect these [lakes] easily, we’d find hundreds of Koonwarras. The problem is grass and trees, but who knows what technology might do in the next 20 or 30 years in terms of laser sensing.”

Seeing a prehistoric feather gives one a little chill of awe. It is tiny, but each delicate filament is etched into the brown shale as clearly as if it blew onto that polar lake just a few days ago.

Rich pulls out other fossils showing fish and plants, beautiful things that are breathtakingly vivid despite their 130-million-year age.

Does Rich find such figures difficult to grasp? “The point is these numbers are so incomprehensible that if next year someone told me it’s 130 billion …” He shrugs. “OK, you add three zeros, so what? I can’t hold that.” He returns the fossils to the cabinet. “It’s just a number. And it just happens to be the field I’ve been working.”