INVESTIGADORES
KATINAS Liliana
artículos
Título:
Fossils indicate an explosive radiation of basal Asteracean lineages and allied families during Oligocene and Miocene times in the Southern Hemisphere
Autor/es:
BARREDA, V.; PALAZZESI, L.; TELLERIA, M. C.; KATINAS, L.; CRISCI, J. V.
Revista:
REVIEW OF PALAEOBOTANY AND PALYNOLOGY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2010
ISSN:
0034-6667
Resumen:
<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES-AR; mso-fareast-language:ES-AR;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --> Much of our knowledge of the past distribution and radiation of Asteraceae and allied families depends on pollen preservation. In recent years, new palynological discoveries are coming to light from southern Africa, Australia, New Zealand, Central and southern South America (Patagonia). Unequivocally assigned morphotaxa from accurately dated sediments have permitted for the first time a comprehensive review of the past distribution of the most important core of the sunflower alliance of families (Menyanthaceae, Goodeniaceae, Calyceraceae and Asteraceae). The main goal of this contribution is to explore the major evolutionary radiation of the basal-most lineages of Asteraceae (Mutisioideae, Barnadesioideae) and allied relatives (Menyanthaceae, Goodeniaceae and Calyceraceae) on the basis of the worldwide fossil pollen records. Several taxa, which today are restricted to isolated geographic regions, were widespread in the Southern Hemisphere during Paleogene times. Menyanthaceae, Goodeniaceae and Mutisioideae (Asteraceae), for example, had a wider distribution in Gondwanan landmasses by the Oligocene and are now drastically reduced in their geographic range. Early Neogene records, in contrast, suggest extinction and diversification events that progressively led to the present day configuration. In broad terms, the distribution of Miocene fossils assigned to this clade coincides with that of their present one (Barnadesioideae, Nassauvieae, Calyceraceae). The major floristic turnovers coincided with the final isolation of Antarctica, leading to cooler, drier, and more seasonal climates that forced the evolution and distribution in space of all these Gondwanan elements.