Format: ORAL

Katharina Nargar1,2, Natascha Wagner1,3, Consolata Nanjala1,4, James Perkins1,4, Stephen J. Bent6, Lars Nauheimer1, Heidi Zimmer7, Stephanie Goedderz1, James A. Nicholls8, Vidushi S. Patel8, Vanessa Neale1,2, Vera Zizka1,9, Claire Micheneau1,10, Janani Jayanthan1, Stephanie Lyon11, Darren M. Crayn1, Lalita Simpson1, Mark Clements7

1 Australian Tropical Herbarium, James Cook University, Cairns, Australia 2 National Research Collections Australia, Commonwealth Industrial and Scientific Research Organisation (CSIRO), Canberra, Australia 3 Department of Systematics, Biodiversity and Evolution of Plants, Georg August University of Göttingen, 37073 Göttingen, Germany 4 College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia 5 Division of Ecology and Evolution, Australian National University, Canberra, Australia 6 National Biodiversity DNA Library, Commonwealth Industrial and Scientific Research Organisation (CSIRO), Brisbane, Australia 7 Centre for Australian National Biodiversity Research (Joint Venture between Parks Australia and CSIRO), Canberra, Australia 8 Australian National Insect Collection, Commonwealth Industrial and Scientific Research Organisation (CSIRO), Canberra, Australia 9 Leibniz Institute for the Analysis of Biodiversity Change, Zoological Research Museum A. Koenig, Bonn, Germany 10 Ctr Int Rech Agronorn Dev, Université La Reunion, La Reunion, France 11 University of Wisconsin-Stevens Point, Wisconsin, USA

Australia harbours a rich and highly endemic orchid flora with over 1,600 species of which over 90 % occur nowhere else. The terrestrial orchid tribe Diurideae is a morphologically diverse and characteristic element of the Australasian orchid flora and comprises nine subgenera and over 1,000 species. The tribe exhibits greatest diversity in Australia where it encompasses ca. 60% of native orchid species, extending into New Zealand, New Caledonia, New Guinea, tropical Asia and the Pacific. Previous phylogenetic studies provided only limited insights into the origins and spatio-temporal evolution of Diurideae lineages due to limited resolution and/or sampling. Here we present a thoroughly sampled phylogenomic study of Diurideae, encompassing all nine subtribes, all recognised genera and the vast majority of species of the tribe. Genome skimming data for over 1,350 Diurideae samples as well as for a broad outgroup sampling across Orchidaceae was generated and assembled either de novo or via reference-guided assemblies. Maximum likelihood analyses were carried out based on concatenated alignments of 62 plastid coding genes and divergence time estimations conducted based on secondary calibrations using BEAST. Biogeographic areas were delineated based on botanical continents and regions following Brummit (2001) and within Australia based on the terrestrial phytoregionalisation sensu Ebach et al. (2015). Range evolutionary scenarios were reconstructed using model-based inference methods as implemented in BioGeoBEARS. This study provides new insights into the diversification and range evolution of tribe Diurideae during the Cenozoic with its profound climatic and vegetational changes and constitutes an unprecedented phylogenomic framework for macroevolutionary studies in Australasian Orchidaceae.