Revista Chilena de Historia Natural 85 (4): 369-392, 2012
SPECIAL FEATURE
Evolution of the Austral-Antarctic flora during the Cretaceous: New insights from a
paleobiogeographic perspective
Forest environments have continuously existed in Antarctica since the late Paleozoic and
only disappeared from this continent since the Neogene. Nevertheless, the structure of these forests underwent substantial
evolutionary changes. During the late Cretaceous, forests dominated by conifers and pteridophytes were gradually replaced by
angiospermdominated forests. Elements common to these Antarctic forests are important constituents of the recent Valdivian Forest.
During the Turonian stage of the Late Cretaceous, the Antarctic Peninsula and Patagonia were reconnected by a land bridge after a
separation since the end of the Jurassic. Using biogeographic tools applied to the palynological and leaf imprint record, outcrops of
Campanian-Maastrichtian age were studied from the Snow Hill, James Ross and Seymour (Marambio) Islands in the James Ross
basin, Antarctica; Skua Bay, Half Three Point, Price Point and Zamek Hill on King George Island, Antarctica, and Rocallosa Point, Cerro
Guido, Las Chinas, Dorotea Hill, Cazador Hill and La Irene in Chilean-Argentinian Patagonia, comparing the current distribution and the
paleogeography, as well as the influence of potential areas of endemism and vicariants events. The analysis indicates that vegetation
evolved under environmental conditions subject to intense volcanic and climatic disturbances, with changes from a period with extreme
greenhouse climate (Turonian-Campanian) to strong cooling during the Maastrichtian. We suggest that a continuous forest existed in
southern South America and Antarctica, which was shaped during the Latest Cretaceous by the presence of marine basins and and
intermittent connection and disconnection of the flora.
Key words:
Antarctica,
Cretaceous, Magellan’s basin, paleobotany, Patagonia.
