Two Canadian scientists have completed a comprehensive portrait of the lush, rainforest-like ecosystem — populated by prehistoric creatures akin to alligators, hippos and flying lemurs — that prevailed some 40 million years ago in what is now Canada’s northernmost landmass: Ellesmere Island.

The study of hundreds of fossilized species, published in the latest issue of the journal Geological Society of America Bulletin, paints a picture of the ancient Arctic that contrasts sharply with the barren and bone-chilling place it is today.

But Ellesmere Island’s rugged and windswept terrain, a bleak domain now ruled by the shaggy muskox, was once teeming with a diverse array of plant and animal life in a long-lost world that’s only recognizable today from Earth’s southern latitudes.

Glimpses of Ellesmere’s extinct rainforest have been provided in previous scientific studies, including several by Saskatchewan-born paleontologist Jaelyn Eberle. Now a professor at the University of Colorado Boulder and curator of fossil vertebrates at the university’s natural history museum, Eberle co-authored the new GSA Bulletin paper with Manitoba scientist David Greenwood, a paleobiologist at Brandon University.

Their exhaustive inventory of the known flora and fauna of the Eocene Arctic, a period that lasted from about 50 million to 38 million years ago, reveals what Eberle calls — in refreshingly unscientific phrasing — “a pretty amazing place” at the northern extreme of the future Canada.

“Who would have guessed we had all of those turtle species and primates living in the ancient Arctic?” Eberle told Postmedia News, adding that, “despite all of the fossil discoveries though, there are still a lot of questions unanswered. The Canadian Arctic was, and still is, the last frontier for paleontology.”

Among the unexpected inhabitants of ancient Ellesmere was the coryphodon, a semi-aquatic mammal resembling the modern hippopotamus and known from fossilized bone and teeth found on the High Arctic island.

Even though Ellesmere was situated nearly as close to the North Pole 50 million years ago as it is today, the coryphodon — notable for its massive size and fang-like tusks — lived in temperate, swampy forests that thrived in the greenhouse-heated planet of the Eocene age.

Coryphodon — which stood up to one metre tall at the shoulder, was about two metres long and weighed 500 kilograms or more — was one of the largest mammals on Earth at the time. A herbivore, it fed on flowers, leaves and marsh vegetation in the summer months and ate pine needles and fungus during the long, dark winter months that marked life at Arctic latitudes — both then and now.

Eberle said she studies the Eocene environment partly to compare its evolutionary features with today’s Arctic. Although the climate warming that the region is undergoing today is happening on a much lesser scale, the Arctic biosphere has nevertheless begun to exhibit significant shifts in the ranges of certain plants and animals.

“The Eocene Arctic biota is arguably our best ‘deep time laboratory’ for understanding and predicting the impacts of current and future global warming on today’s polar biota,” Eberle said.

Eberle and Greenwood’s prehistoric portrait of the region includes fossil evidence gathered from nearby Axel Heiberg Island and other sites in the vicinity of Ellesmere Island.

The region’s fossil deposits are considered a world-class treasure among vertebrate paleontologists, several of which — including Eberle — recently expressed concerns about a proposed coal-mining project near a popular research site on Ellesmere Island.

In 2010, the controversial proposal — potentially one of the planet’s most northerly industrial operations — hit a major roadblock after a Nunavut review agency ruled that “the high likelihood of immitigable impacts” to wildlife and globally significant fossil beds demanded that the project be “modified or abandoned” by its British Columbia-based proponent.

The recommendation was hailed at the time by the U.S.-based Society of Vertebrate Paleontology as a major victory for science.

“The news couldn’t be better,” society president Blaire Van Valkenburgh said in a March 2010 statement. “This is the strongest possible outcome in our favour.”

Less than a year earlier, Eberle had revealed the discovery on of a set of coryphodon teeth on Ellesmere Island that was called potential “smoking-gun” evidence showing how a host of prehistoric mammal species arrived in North America.

Eberle’s submission to the review board, later quoted in the agency’s report to the federal government, said the island’s fossils “are a part of Nunavut’s heritage and a legacy for generations of Nunavut children. These fossils, and the clues they reveal about Nunavut’s ancient past, are irreplaceable.