Casuarinaceae, Fagaceae, and other plant megafossils from Kaikorai Leaf Beds (Miocene) Kaikorai Valley, Dunedin, New Zealand

Abstract

Fruiting cones (infructescences) of Casuarinaceae and fruits of more than five further angiosperms are preserved in diatomite at Frasers Gully, Kaikorai Valley, Dunedin district. The floral assemblage also includes possible immature cones of Casuarinaceae, and many leaves. The majority of the leaves belong to Fagaceae but Proteaceae and other families are present. The beech leaf fossils for which the form-genus Nothofagaphyllites is proposed are all denticulate and acuminate. They include rare notophylls but most are large microphylls. Their secondary veins are regularly spaced, straight, or slightly curved. Tertiaries are orthogonal reticulate or percurrent forked. Cuticular details are unknown. Leaf form is reminiscent of living New Caledonian species of Nothofagus with which one of the fossil fruits is also compared. All Fagaceae fossils from the deposit show some affinities with the brassii (pollen) section of Notho!agus. Kaikorai Leaf Beds are a lacustrine deposit within the Dunedin Volcanic Complex of Miocene age (Waiauan local stage at the base) within the range 10–13 Ma.