A new Eocene Araucaria from Seymour Island, Antarctica: evidence from growth form and bark morphology

Araucarian conifers are an important component of Cretaceous through Paleogene floras in the Antarctic Pensinsula. A well-preserved Eocene petrified trunk from Seymour Island, Antarctica reveals the growth form and bark morphology that, along with wood anatomical characteristics, places the tree within Araucaria. The tree was at least 14 m tall with a monopodial habit and horizontally wrinkled bark. Wood-decaying fungi colonized the trunk after it had fallen to the forest floor. The fungi invaded the trunk through the pith and initially along ray cells leaving strongly lignitized cells relatively intact. This indicates preferentially consumption of sugars suggesting these fungi formed the first stages of nutrient recycling within this Eocene ecosystem.