A new Late Triassic phytogeographical scenario in westernmost Gondwana

CÉSARI, SILVIA; COLOMBI, CARINA E.

NATURE COMMUNICATIONS

Nature Publishing Group

Año: 2013 p. 1 - 6

2041-1723

Floral provincialism within the Triassic phytogeographic realm of Gondwana is still poorly resolved, mainly due to the scarcity of detailed studies in key sections. New palynological assemblages from the Ischigualasto Formation, northwestern Argentina (231- 225 Ma), change significantly the phytogeographic interpretation for the Carnian?Norian in the westernmost Gondwana. This region was previously considered part of the southern floral Ipswich Province. However, the presence of diagnostic equatorial Thetyan species within assemblages dominated by Gondwanan taxa allows us to refer the palynofloras to the Onslow Province. The new data extend the Onslow floral belt, previously recognized from the western edge of Tethys to Timor, to the western margin of South America. This has implications for paleophytogeography, paleoclimate reconstructions and also the paleoecology of a Triassic ecosystem which has yielded significant vertebrate remains and is regarded as important in the early evolution of groups such as the Dinosauria.