Camels tracked back to large ancestor
Ships of the desert they may be, coping with heat and dryness, but camels may have evolved from a large ancestor that lived in the Canadian High Arctic.
The world was warmer then, during the mid-Pliocene Epoch about 3.5 million years ago, and the High Arctic camel lived in a boreal-type forest.
Fossil evidence of the animal's existence was announced today (NZT) by the Canadian Museum of Nature and published in online journal Nature Communications.
The 30 fossil fragments of a leg bone were found on Ellesmere Island, in northern Canada, during the summers of 2006, 2008 and 2010.
The High Arctic camel was about 30 per cent larger than modern counterparts, weighing about 900kg and standing about 2.7m high at the shoulders. It moved into the far northern latitudes during a time when global temperatures were thought to be 2-3 degrees Celsius higher than now, with that rise greatly amplified in the Arctic meaning temperatures on Ellesmere were 14-22C higher.
The Canadian Museum of Nature said information about the collagen, the dominant protein found in bone, of the High Arctic camel, combined with anatomical data showed it was likely the same lineage as the ancestor of modern camels Paracamelus.
"We now have a new fossil record to better understand camel evolution, since our research shows that the Paracamelus lineage inhabited northern North America for millions of years," Canadian Museum of Nature vertebrate palaeontologist Dr Natalia Rybczynski said.
"The simplest explanation for this pattern would be that Paracamelus originated there. So perhaps some specialisations seen in modern camels, such as their wide flat feet, large eyes and humps for fat may be adaptations derived from living in a polar environment."
The discovery extended the range of camels in North America northward by about 1200km.
Full confirmation that the bones belonged to a camel came from a new technique called collagen fingerprinting pioneered by Dr Mike Buckley at Manchester University in England. Profiles produced by the technique can be used to distinguish between groups of mammals.
Minute amounts of collagen were extracted from the fossils. Using chemical markers for the peptides that make up the collagen, a collagen profile for the fossil bones was developed. That profile was compared with those of 37 modern mammal species, as well as that of a fossil camel found in Yukon, which is also in the Canadian Museum of Nature's collections.
The collagen profile for the High Arctic camel most closely matched those of modern camels, specifically one-humped dromedaries as well as the Yukon giant camel, which is thought to be Paracamelus.