A Lagerstatte from Australia provides insight into the nature of Miocene mesic ecosystems

Reduced precipitation in the Miocene triggered the geographic contraction of rainforest ecosystems around the world. In Australia, this change was particularly pronounced; mesic rainforest ecosystems that once dominated the landscape transformed into the shrublands, grasslands, and deserts of today. A lack of well-preserved fossils has made it difficult to understand the nature of Australian ecosystems before the aridification. Here, we report on an exceptionally well-preserved rainforest biota from New South Wales, Australia. This Konservat-Lagerstatte hosts a rich diversity of microfossils, plants, insects, spiders, and vertebrate remains preserved in goethite. We document evidence for several species interactions including predation, parasitism, and pollination. The fossils are indicative of an oxbow lake in a mesic rainforest and suggest that rainforest distributions have shifted since the Miocene. The variety of fossils preserved, together with high fidelity of preservation, allows for unprecedented insights into the mesic ecosystems that dominated Australia during the Miocene.

Automated summary

Reduced precipitation in the Miocene caused rainforest ecosystems to contract globally, particularly in Australia where they transformed into shrublands, grasslands, and deserts. The lack of well-preserved fossils has hindered understanding of pre-aridification Australian ecosystems. This study presents an exceptionally well-preserved rainforest biota in New South Wales, Australia, containing a diverse assemblage of microfossils, plants, insects, spiders, and vertebrate remains. These fossils indicate a mesic rainforest surrounding an oxbow lake and suggest shifts in rainforest distributions since the Miocene. The high fidelity of preservation allows for unprecedented insights into Miocene-dominated mesic ecosystems in Australia.