Collections technician and researcher Oliver Haddrath holds a partial skull and antlers from a prehistoric deer specimen at the Royal Ontario Museum in Toronto on Thursday.Photography by Sammy Kogan/The Globe and Mail
For visitors wandering among mastodon skeletons and other impressive remains from the Pleistocene epoch at Toronto’s Royal Ontario Museum, a non-descript piece of cranium with broken stubs of antlers may not be the most arresting sight.
Yet the bony fragment inside the glass case is a tantalizing clue to the vanished world that once existed where the city stands today – a nascent wilderness that emerged from the frozen mantle of the ice age more than 11,000 years ago.
Now, for the first time, scientists have a genetic profile of the fossil, which is called Torontoceros after its hometown, but also goes by its urban transit handle: “the subway deer.”
The results confirm that Torontoceros was indeed a deer – but one whose appearance and traits must have diverged substantially from those that frequent the ravines and backyards of Toronto today.
In that contrast, researchers say, lies the mark of a world that was in rapid transition.
“This animal would have seen a landscape completely different than the one we know,” said Oliver Haddrath, a collections technician at the ROM who specializes in the retrieval and analysis of DNA from the museum’s specimens.
Mr. Haddrath points to the area where DNA was sampled from the partial skull and antlers. The fossil has been named the Torontoceros after its hometown.
The work is documented in a study that was recently accepted for publication in the journal Biology Letters.
It also adds a new and fascinating chapter to the story of the subway deer, so called because the only known specimen was discovered in 1976 by an employee of the Toronto Transit Commission when work crews were excavating in the city’s west end as part of a subway line extension.
When the specimen was donated to the ROM for examination, experts at the time were challenged to place it in the family tree of known antlered herbivores.
On one hand, the part of the skull that was present is consistent with a deer. But the heavy antlers, which spread horizontally from their point of attachment, are closer in appearance to those of a caribou.
An initial study, published in 1982, called it a deer, but others have since argued that it is more likely to be a caribou relative. And with no other specimens, that seemed to be where the matter was likely to stay.
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What has changed is the growing power of genetic tools to extract new information from such rare finds.
The current study originated when a team from Trent University in Peterborough, Ont., approached the ROM to see about analyzing DNA from various deer, elk, moose and caribou specimens in the museum’s collection.
The goal was to glean information about how the genetic diversity within these species changed in historic times in response to environmental pressures and what that might portend for their present-day counterparts.
“We wanted to build this temporal data set and compare it to modern samples,” said Aaron Shafer, an associate professor of wildlife and applied genomics at Trent.
What Dr. Shafer and his colleagues did not expect was Torontoceros. Once museum staff told them about it, they were game to add it to their study. The only question was whether any DNA could be recovered from the ancient antlers.
“It’s actually the oldest thing we’ve tried,” Mr. Haddrath said.
Even older DNA can be recovered when specimens are found buried in Arctic permafrost and genetic material has lain frozen and inert for tens of thousands of years.
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In temperate places such as Toronto, where the soil is repeatedly subjected to an annual freeze-thaw cycle, it’s a different story.
“Depending on how close it is to the surface, that can really take the stuffing out of DNA,” Mr. Haddrath said.
Incredibly, the attempt worked. Mr. Haddrath and Camille Kessler, a PhD student at Trent, managed to find DNA that had persisted in the antlers.
Dr. Shafer realized the team now had a chance to settle the question of the creature’s identity once and for all.
“It became very clear early on it wasn’t caribou,” he said.
Instead, the DNA suggested the original paper was correct: Torontoceros was a deer. They could also add to this picture because the DNA suggested it was related to mule deer and white-tailed deer, but had diverged before those two modern species split from each other.
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The physical resemblance to caribou makes sense in the context of the environment the species lived in. At that time, the site of present-day Toronto was an open boreal terrain, not the thickly wooded landscape it would later become. And when trees are not so dense, large, spreading antlers are not an impediment.
Hendrik Poinar, an evolutionary geneticist at McMaster University in Hamilton who was not involved with the study, said Dr. Shafer and his colleagues make a good case for the “rapid recent diversification” leading to a deer species like Torontoceros that frequented open, grassy areas. However, he added that mastodon and beaver fossils from the same time period suggest there were also wetlands throughout the region.
As for Torontoceros, and why it went extinct, “the question is, what was the population size,” Dr. Poinar said. This is information that could emerge from further studies of the ROM specimen if the entire genome can be sequenced to reveal more about the species’s diversity.