title: Mid-Pliocene warm-period deposits in the High Arctic yield insight into camel evolution.
abstract: The mid-Pliocene was a global warm period, preceding the onset of Quaternary glaciations. Here we use cosmogenic nuclide dating to show that a fossiliferous terrestrial deposit that includes subfossil trees and the northern-most evidence of Pliocene ice wedge casts in Canada's High Arctic (Ellesmere Island, Nunavut) was deposited during the mid-Pliocene warm period. The age estimates correspond to a general maximum in high latitude mean winter season insolation, consistent with the presence of a rich, boreal-type forest. Moreover, we report that these deposits have yielded the first evidence of a High Arctic camel, identified using collagen fingerprinting of a fragmentary fossil limb bone. Camels originated in North America and dispersed to Eurasia via the Bering Isthmus, an ephemeral land bridge linking Alaska and Russia. The results suggest that the evolutionary history of modern camels can be traced back to a lineage of giant camels that was well established in a forested Arctic.
authors: Department of Palaeobiology, Canadian Museum of Nature, Ottawa, Ontario K1P 6P4, Canada. nrybczynski@mus-nature.ca
authors: Natalia
authors: N
authors: Rybczynski
authors: John C
authors: JC
authors: Gosse
authors: C Richard
authors: CR
authors: Harington
authors: Roy A
authors: RA
authors: Wogelius
authors: Alan J
authors: AJ
authors: Hidy
authors: Mike
authors: M
authors: Buckley
mesh_terms: D000818:Animals; D001110:Arctic Regions; D005075:Biological Evolution; D001842:Bone and Bones / Q000033:anatomy & histology / Q000648:ultrastructure; D002162:Camelus / Q000033:anatomy & histology / Q000502:physiology*; D003094:Collagen / Q000378:metabolism; D005580:Fossils; D005843:Geography; D006358:Hot Temperature; D007553:Isotope Labeling; D020957:Nunavut; D011309:Preservation, Biological; D013997:Time Factors
chemical_list: D003094:Collagen