Abstract Detail

Macroevolution

Diversification dynamics of the temperate Australian flora, maintenance of species diversity and radiations.

Many of the Australian biota have ancient Gondwanan origins, going back to the Cretaceous. Here, we investigate whether differences in plant richness in the southwest Australian (SWA) biodiversity hotspot and southeast Australian (SEA) regions of the Australian continent can be attributed to higher net diversification, more time for species accumulation, or both. We assembled dated molecular phylogenies for the 21 most species-rich flowering plant families found across mesic temperate Australia, encompassing both SWA and SEA regions, and applied a series of diversification models to investigate responses across different groups and timescales. We show that the high richness in SWA can be attributed to a higher net rate of lineage diversification and more time for species accumulation. Different pulses of diversification were retrieved in each region. A decrease in diversification rate across major flowering plant lineages at the Eocene– Oligocene boundary (ca 34 Ma) was witnessed in SEA but not in SWA. In addition, we present in this 2020 symposium recent unpublished results of more recent diversification dynamics from the Oligocene–Miocene through to the present. Our study demonstrates the importance of historical diversification pulses and differential responses to global events as drivers of present-day diver- sity. More broadly, we show that diversity within the SWA biodiversity hotspot is not only the result of recent radiations, but also reflects older events over the history of this planet.

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1 - University of Adelaide, Biological Sciences, North Terrace campus, Adelaide, South Australia, 5070, Australia

Keywords:
macroevolution
evolution
Diversification
Evolutionary radiation
Australian flora
Biodiversity.

Presentation Type: Oral Paper
Session: MACRO2, Macroevolution II
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 10:45 AM
Number: MACRO2004
Abstract ID:562
Candidate for Awards:None