INVESTIGADORES
OLIVERO Eduardo Bernardo
congresos y reuniones científicas
Título:
CRETACEOUS EVIDENCE OF ASTERALEANLIKE POLLEN IN ANTARCTICA
Autor/es:
BARREDA, V. D.; LUIS PALAZZESI; MARIA C. TELLERÍA; EDUARDO OLIVERO
Lugar:
Mendoza
Reunión:
Congreso; 4th International Palaeontological Congress; 2014
Institución organizadora:
IPA- CONICET Mendoza
Resumen:
Asterales is an order of flowering plants that includes the highly diverse Asteraceae ?daisy family?
along with ten other phylogenetically related families. Asterales appear to have originated in the
Cretaceous, but no fossils from this period have been found to date to support this assumption
regarding the origin of this group. Here we report new Asteralean-like fossil pollen grains from
Antarctica that shed new light on the early evolution and diversification of Asterales. We recovered
these specimens from Campanian/Maastrichtian sediments of the Santa Marta, Snow Hill Island
and Lopez de Bertodano formations, on the James Ross and Vega islands, in Antarctica. We scored
75 binary pollen characters from 4 fossil forms and 55 extant species chosen to represent all families
and tribes in Asterales. We conducted parsimony analyses to assess the phylogenetic position
of each fossil using a highly supported molecular phylogenetic tree as backbone constraint. Our
phylogenetic analysis places the new fossils within the early-diverging branches of Asteraceae and
its sister Calyceraceae and Goodeniaceae. These fossils display some but not all the synapomorphies
of the crown group, and hence leading us to infer that these fossils might represent members of the
stem lineage. We reveal that some Asteralean lineages evolved in Antarctica during the Cretaceous,
survived the K?P global extinction event, and radiated into the world?s highest latitudes of
Gondwana by the Paleogene.