The most Canadian animal? It鈥檚 not the beaver that marks the nickel, the moose that pervades souvenir shops across the country, or the loon that gave the one-dollar 鈥渓oonie鈥� its name.

In fact, the spiny softshell turtle is Canada鈥檚 most distinct animal in evolutionary terms, researchers from Simon Fraser University show in a first-of-its-kind study.

Arne Mooers, a biodiversity professor who led the research,says it means the threatened freshwater turtle found in southern Ontario and Quebec has spent the longest stretch of time evolving independently from other species in Canada.

The researchers started by building a 鈥渢ree of life鈥� using Canada鈥檚 official list of species, which includes 222 mammals, 674 birds, 48 amphibians and 49 reptiles.

They identified the top 20 most isolated species for each group and found the spiny softshell turtle topped the rankings, representing nearly 180 million years of independent evolutionary history, while Canada鈥檚 lone marsupial, the Virginia opossum, was the top-ranked mammal at nearly 160 million years.

The softshell turtle is followed by the mudpuppy, the only completely aquatic amphibian in Canada, and a species that Mooers describes as 鈥渞eally cute.鈥�

鈥淚t can grow as long as a small cat, and it can live for 30 years,鈥� he says.

The ranking not only highlights species that are often 鈥渨eird and wonderful,鈥� like the mudpuppy, he says, but also offers a kind of 鈥渢riage鈥� tool for conservation efforts.

A species that has close relatives in other countries may be isolated and threatened in Canada, and a high ranking for evolutionary distinctiveness could help conservationists determine which species to focus on, he says.

鈥淚f we have limited resources, then this could be one way to help us decide what to do, and say, 鈥榃ell this one really is very different from everything else, and we鈥檝e got a measurement of that so maybe we should make sure we don鈥檛 lose this species.鈥欌��

It鈥檚 one of many ways to assess species, but it is a 鈥渘ew way,鈥� adds Mooers, a member of the Committee on the Status of Endangered Wildlife in Canada.

He says the study published this month in the Canadian Field-Naturalist, a peer-reviewed journal, is the first to create scores for the evolutionary distinctiveness of species in a particular country, going deeper than the species鈥� global ranking.

鈥淚f you do global conservation, you want the global list, but if you鈥檙e interested in your country, maybe you want a country-specific list, and they might not be the same.鈥�

Overall, the researchers found most of the species with high evolutionary distinctiveness rankings in Canada were amphibians and reptiles.

The tree of life for mammals in Canada is 鈥渧ery weird,鈥� Mooers notes, because it includes the country鈥檚 only marsupial, the Virginia opossum.

The opossum pushes the mammal family tree back to 158.8 million years, but the rest of the top-ranked mammals are more closely related to each other.

They range from about 24 million years of independent evolution for the pallid bat to close to 64 million for the North American porcupine, the study says.