XVI International Botanical Congess

In the Late Cretaceous, the Antarctic Peninsula held a crucial high latitude position linking the southern continents during the radiation and diversification of the angiosperms. Fossil plants from the Hidden Lake Formation (Coniacian) and the Santa Marta Formation (Santonian-Campanian) on James Ross Island, east of the northern peninsula, provide new evidence about forests with a diverse angiosperm component flourishing in the region. Although there is no cuticle present, the leaf impressions are excellent and show intricate detail of leaf architecture. Many of these ancestral leaf fossils cannot be clearly assigned to modern families. Multivariate statistical methods were used to cluster the leaves using characters such as the style of the apex and base, marginal features, and primary, secondary and tertiary venation patterns. The resulting morphotypes are compared with fossil and modern leaves and their geographic and stratigraphic distribution to aid understanding of the role of Antarctic floras in the evolution of angiosperms across Gondwana.