The tectonic setting of the Caribbean Region: Key in the radical Late Cretaceous-Early Paleocene South American land-mammal turnover

ORTIZ-JAUREGUIZAR, EDGARDO; PASCUAL, ROSENDO

4th European Meeting on the Palaeontology and Stratigraphy of Latin America

Instituto Geológico y Minero de España

Lugar: Madrid; Año: 2007; p. 301 - 307

The Caribbean Region has played a crucial role in the biogeography and evolution of North and South American Cretaceous to Recent faunas. According to the fossil record, an interchange of vertebrates began during the Late Cretaceous-Early Paleocene span. The arrival of North American immigrants (particularly therians) during latest Cretaceous-earliest Paleocene had a radical influence on the composition of the South American mammal communities. During Late Cretaceous, these communities were dominated by autochthonous (Gondwanan) groups, but during Early Paleocene 70% of the mammals were derived from North American immigrants, and from the Late Paleocene on, almost all the South American mammals (except platyrrhine primates and caviomorph rodents) were derived from North American immigrants. Since none geological evidence supports the existence of a dry land connection between the Americas during the Late Cretaceous-Early Paleocene span, some kind of corridor or filter (maybe a stepping-stone as a volcanic arc) had to be originated during a brief (geologically speaking) period, particularly active during a lower sea-level at the Late Cretaceous-earliest Paleocene span, to permit the beginning of the interamerican land vertebrates exchange.