Epiphyllous fungi and leaf physiognomy indicate an ever-wet humid mesothermal (subtropical) climate in the late Eocene of southern New Zealand

• Diverse epiphyllous fungi are described from the early Eocene of New Zealand.
• The fungi and CLAMP analyses suggest a mesothermal and ever-wet climate.
• This is agrees with reduced latitudinal temperature gradients during the Eocene.
• High precipitation and humidity suggest moisture transport from lower latitudes.

A diverse group of epiphyllous fungi from at least 10 genera as well as numerous germlings were isolated from late Eocene leaf litter, preserved as carbonaceous material associated with the Pikopiko Fossil Forest, near Tuatapere, Southland, New Zealand. These fungi are associated with a variety of angiosperm leaves and, together with CLAMP analyses of the fossil leaf assemblages at the site, suggest that climatic conditions in the southern South Island of New Zealand at a palaeolatitude of ~ 54°S during the late Eocene (ca. 35 Ma) were mesothermal (subtropical) and had near-permanent high vapour pressure. The mesothermal conditions at mid-latitudes in New Zealand are concurrent with reduced latitudinal temperature gradients during the Eocene. High precipitation rates and humidity are suggestive of high moisture transport from lower latitudes.