Diversity and evolution of Araucariaceae: in pursuit of ghost lineages from South American fossils

ESCAPA, IGNACIO; CÚNEO, RUBÉN; WILF, PETER

Melbourne

Congreso; XVIII International Botanical Congress; 2011

In South America, the family Araucariaceae is represented by two living species of the genus Araucaria section Araucaria, A. araucana and A. angustifolia, which along with the Australasian species of Araucaria, Agathis, and Wollemi define a mostly Southern Hemisphere distribution for the family. In addition, the Araucariaceae shows an extended fossil record with occurrences recognized since the early Mesozoic in both hemispheres. Stratigraphic adjustment of phylogenetic hypotheses for the family indicates that divergences leading to the major clades probably occurred as early as the Early Jurassic. Despite the extensive fossil record of the family, the phylogeny indicates ghost lineages for several genera and sections. We discuss the rich record of the family in South America and its implications for understanding the evolutionary relationships and the geographic distributions of past and present species. Several of these taxa fill remarkable temporal and morphological gaps in the record of Araucariaceae and therefore provide a more complete assessment of the evolutionary history of the group. New findings from Jurassic, Cretaceous and Paleogene localities in Argentina and Colombia are highlighted in this evolutionary context.