Detailed comparisons of the collagen proteins trapped and preserved within the bone fragments to those produced by 37 living mammal species indicate that the ancient creature was most closely related to today’s dromedary camel (the species with one hump), the researchers report online Tuesday in Nature Communications.
The new findings are “pretty exciting,” says Grant Zazula, a paleontologist with the Government of Yukon in Whitehorse, Canada. “It’s amazing to be able to get collagen out of fossils that are 3.5 million years old.” The remarkable preservation, Rybczynski says, likely stems from a coating of iron minerals that helped seal the bones, as well as the natural cold-storage available in the Arctic.
Considering the proportions of the bone fragments, the camel was a giant, probably about 2.7 meters tall at the shoulder-almost 30% larger than its modern relatives are. The moose-sized mammal likely tipped the scales at 900 kilograms at the end of the summer browsing season but then slimmed down as it drew on fat reserves in its hump to sustain itself through the harsh Arctic winter.
The Ellesmere Island site is about 1200 kilometers farther north than any previous camel find, Rybczynski says. Fossils unearthed at a location about 10 kilometers away from the camel find, and from rocks of approximately the same age, reveal that the landscape hosted an open forest punctuated with peatlands and inhabited by bears, rabbits, beavers, a greyhound-sized deerlet, and a pony-sized, three-toed horse. Annual average temperature in the area was about -1.4°C, barely below freezing but still about 18°C warmer than the modern average.
The new findings indicate that the high Arctic, including Ellesmere Island in northeastern Canada and the land bridge that connected Alaska to northeastern Asia, was no evolutionary backwater. “The Bering land bridge wasn’t just a temporary stop on the way to and from Asia,” Zazula says. “It was a center of evolution.”