期刊
GLOBAL AND PLANETARY CHANGE
卷 123, 期 -, 页码 400-413出版社
ELSEVIER
DOI: 10.1016/j.gloplacha.2014.07.016
关键词
West Antarctica; South America; land connection; Early Paleogene; South American and Antarctic native ungulate
资金
- Instituto Antartico Argentino (PICTA)
- Agencia Nacional de Promocion Cientifica y Tecnologica (ANPCYT) [PICT 0365, PICTO 0093]
- Universidad Nacional de La Plata (UNLP) [11-N677]
- Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET)
The biogeographic hypothesis more accepted today is that Antarctica (West Antarctica) and southern South America (Magellan region, Patagonia) were connected by a long and narrow causeway (Weddellian Isthmus) between the Antarctic Peninsula and South America since the Late Cretaceous (Campanian) until the Early Paleogene allowing terrestrial vertebrates to colonize new frontiers using this land bridge. Stratigraphically calibrated phylogenies including large, terrestrial native ungulates Litopterna and Astrapotheria taxa reveal long ghost lineages that extended into the Late Paleocene and provide evidence for the minimum times at which these native ungulates were present both on Antarctica and South America. Based on these results we estimate that the Weddellian Isthmus was functional as a land bridge until the Late Paleocene. Our data place the disconnection between Antarctica and South America in the Late Paleocene, indicating that the terrestrial faunistic isolation (Simpson's splendid isolation) in South America begun at the end of the Paleocene (similar to 56 to 57 m.y.). This faunistic isolation is documented to have occurred at least 25 Ma before the existence of deep-water circulation conditions in Drake Passage (similar to 30 m.y.) based on the onset of seafloor spreading in the west Scotia Sea region. We hypothesize that in the early stages of extension (Late Paleocene, similar to 55 m.y.) a wide and relatively shallow epicontinental sea developed between the Antarctic Peninsula and South America drowning the Weddellian Isthmus and preventing the faunal interchange for obligate cursorial terrestrial forms. (C) 2014 Elsevier B.V. All rights reserved.
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