Araucarian leaves and cone scales from the Loreto Formation of Río de Las Minas, Magellan Region, Chile

Abstract

Cone scales and leaves of the Araucariaceae are reported from the Loreto Formation in Río de Las Minas, Punta Arenas, Chile. Two types of cone scales including one new species, Araucarites alatisquamosus are recognized. They are similar to Araucaria section Eutacta. Two types of leaves are assigned to Araucaria nathorstii Dusén, and one new type is distinguished in the specimens from the type locality of A. nathorstii. A narrow leaf type is identical to Dusén’s “Blätter der sterilen Zweige (leaves of sterile shoot)” of A. nathorstii, and a broad leaf type is identical to his “Blätter der fertilen Zweige (leaves of fertile shoot)”. Both types show characters of leaves of section Araucaria as suggested by earlier studies. A smaller leaf type differs from the original description of A. nathorstii, and consists of small appressed leaves with the obtuse apex and stomatal orientation that are the characteristic of the section Eutacta. The occurrence of leaves and cone scales similar to section Eutacta suggest the presence of araucarians close to this section in southernmost South America during the Eocene–early Oligocene, and provide evidence for the wide distribution and diversity of genus Araucaria relatives in South America during the Paleogene.