Biodiversity and palaeoecology of Foulden Maar: an early Miocene Konservat-Lagerstatte deposit in southern New Zealand

This paper highlights the biodiversity and palaeoecology of the 23 million year old Foulden Maar, the first Konservat-Lagerstatte deposit described from New Zealand and a key site for reconstructing early Miocene Southern Hemisphere terrestrial ecosystems. The 1000-m-diameter, ca 200-m-deep Foulden Maar volcanic crater lake was a closed system with anoxic bottom waters, capturing and preserving in exquisite detail organisms from the lake and adjacent rainforest. The fossils include numerous leaves, flowers with in situ pollen, fruits, seeds, fish and arthropods. Surrounding Foulden Maar was an evergreen, Lauraceae-dominated notophyll vine forest with a diverse understorey, lianes, epiphytes and mistletoes. Diverse pollination and seed dispersal modes are evident. Fish include larval to adult stages of articulated specimens of Galaxias, some with preserved soft tissue and a species of eel resembling Anguilla. The arthropod fauna comprises ca 20 families in the orders Araneae (spiders), Plecoptera (stoneflies), Odonata (dragonflies), Isoptera (termites), Hemiptera (true bugs), Diptera (true flies), Coleoptera (beetles), Trichoptera (caddis flies) and Hymenoptera (wasps, ants and bees), representing faunas typical of soil, leaf litter, forest floor or freshwater habitats. Many fossil taxa have close relatives in the extant New Zealand biota; others are now locally extinct. Coprolites containing quartz sands sourced from outside the lake indicate the presence of volant birds, presumably waterfowl. The Foulden Maar Lagerstatte is crucial for reconstructing Miocene lake and forest ecosystems in New Zealand, particularly the terrestrial arthropod component.