Mesozoic and Cenozoic record of Araucaria from Patagonia: integrating morphological information into the genus phylogeny.

ESCAPA, IGNACIO; CÚNEO, RUBÉN; WILF, PETER

Providence

Congreso; Botany 2010; 2010

The conifer family Araucariaceae is one of the most emblematic plant groups of the Southern Hemisphere, where its extant distribution is confined. The family originally included two genera, Agathis and Araucaria, and recently a third one was added: the monotypic Wollemia. Araucaria shows an extended fossil record with species recognized since the early Mesozoic in both hemispheres. The record of Araucaria in Patagonia can be traced from the Early Jurassic through present. Fossil and living Araucaria species are generally divided into four sections: Bunya , Intermedia , Araucaria (= Columbea ) and Eutacta. Fossil species of Araucaria , especially those preserving seed cones, were often assigned to a particular section within the genus based on few characters. Previous phylogenetic analysis of Araucaria have exclusively included molecular characters and therefore fossils were not considered. We discuss the high diversity of fossil Araucaria in Southern South America, including several new findings from the Jurassic, Cretaceous and Paleogene. This extensive fossil record is evaluated in a morphological phylogenetic matrix that also includes all the living species of Araucaria and selected other representatives of the family. In this context, the first record and diversification of the Araucaria sections are discussed. Further investigations on this subject must include revisions of extant and fossil species in order to determine new morphological characters, the extension of the taxon sampling, and the combination with molecular data. Additionally, considerations on the biogeography of the family in the southern hemisphere are considered on light of the new records.