Eocene Patagonia Fossils of the Daisy Family

VIVIANA BARREDA; LUIS PALAZZESI; MARÍA C. TELLERÍA; LILIANA KATINAS; JORGE CRISCI; MAURO PASSALIA; RODOLFO CORSOLINI; RAFAEL RODRÍGUEZ BRIZUELA; FLORENCIA BECHIS

SCIENCE

AMER ASSOC ADVANCEMENT SCIENCE

Lugar: Washington DC; Año: 2010 vol. 329 p. 1621 - 1621

0036-8075

Morphological, molecular and biogeographical information bearing on early evolution of the sunflower alliance of families suggest that the clade containing the extant sunflower family (Asteraceae) differentiated in South America during the Eocene, however paleontological studies on this continent has failed to reveal a conclusive support to this hypothesis. Here we present the first unequivocally fossil head-like inflorescence and associated pollen grains from the Eocene of Patagonia, southern Argentina, which exhibit morphological features today recognized in taxa phylogenetically close to the root of the Asteracean tree, such as Mutisioideae and Carduoideae. This discovery provides the first strong paleobotanical support to the hypothesis of a South American origin of Asteraceae and an Eocene age of divergence. Moreover, this record joined with others from the Paleogene of Africa and Australia, would suggest that an ancestral stock of Asteraceae may have formed part of a Geoflora developed in southern Gondwana before the onset of continental fragmentation. This is the first capitulum of Asteraceae in the fossil record and perhaps the earliest indirect evidence of bird pollination in the family.