A new 'tapir' from Ellesmere Island, Arctic Canada - Implications for northern high latitude palaeobiogeography and tapir palaeobiology
Palaeogeography Palaeoclimatology Palaeoecology
Eocene Arctic palaeobiogeography tapir Eureka sound group early eocene mammals vertebrates phylogeny climate forest middle Tapir Bibliography
The oldest and northernmost record of the tapir lineage, Thuliadanta mayri gen. et sp. nov. from Ellesmere Island, Arctic Canada (78 degrees 50'N) implies that tapiroid evolution was well underway by early Eocene (Wasatchian) time in northern high latitudes, and raises the possibility of a North American origin for the group. Phylogenetic analyses place the new Arctic tapir as the sister group to the later more advanced Desmatotherium, Colodon, and Irdinolophus. A phylogenetically-derived biogeographic reconstruction posed here suggests the tapir lineage may represent a rare instance of counterflow wherein an exotic North American taxon invaded Asia during the early Eocene. Moreover, Thuliadanta seems a plausible ancestor to Desmatotherium from both continents, suggesting that this branch of the tapir lineage may have originated at high latitudes and subsequently dispersed from there to mid-latitudes. Thuliadanta's occurrence on Ellesmere Island indicates that northern high latitudes should also be evaluated as a potential source area for some of the exotic taxa appearing in mid-latitudes during Eocene time. Using today's tapirs, and specifically the mountain tapir, as analogs, Thuliadanta seems a plausible year-round inhabitant in the mild temperate lowland forests of the Eocene High Arctic. (c) 2005 Elsevier B.V. All rights reserved.