Global history of the ancient monocot family Araceae inferred with models accounting for past continental positions and previous ranges based on fossils

Authors

  • Lars Nauheimer,

    1. Systematic Botany and Biology, Department of Biology, University of Munich (LMU), Menzinger-Str. 67, 80638 Munich, Germany
    2. Present address: Molecular Evolution and Systematics of Plants, Institute of Biology, University Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
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  • Dirk Metzler,

    1. Evolutionary Biology, Department of Biology, University of Munich (LMU), Grosshaderner-Str. 2, 82152 Planegg-Martinsried, Germany
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  • Susanne S. Renner

    1. Systematic Botany and Biology, Department of Biology, University of Munich (LMU), Menzinger-Str. 67, 80638 Munich, Germany
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Authors for correspondence:
Lars Nauheimer
Tel: +49 89 17861250
Email: l.nauheimer@gmail.com
Susanne Renner
Tel: +49 89 17861250
Email: renner@lrz.uni-muenchen.de

Summary

  • The family Araceae (3790 species, 117 genera) has one of the oldest fossil records among angiosperms. Ecologically, members of this family range from free-floating aquatics (Pistia and Lemna) to tropical epiphytes. Here, we infer some of the macroevolutionary processes that have led to the worldwide range of this family and test how the inclusion of fossil (formerly occupied) geographical ranges affects biogeographical reconstructions.
  • Using a complete genus-level phylogeny from plastid sequences and outgroups representing the 13 other Alismatales families, we estimate divergence times by applying different clock models and reconstruct range shifts under different models of past continental connectivity, with or without the incorporation of fossil locations.
  • Araceae began to diversify in the Early Cretaceous (when the breakup of Pangea was in its final stages), and all eight subfamilies existed before the K/T boundary. Early lineages persist in Laurasia, with several relatively recent entries into Africa, South America, South-East Asia and Australia.
  • Water-associated habitats appear to be ancestral in the family, and DNA substitution rates are especially high in free-floating Araceae. Past distributions inferred when fossils are included differ in nontrivial ways from those without fossils. Our complete genus-level time-scale for the Araceae may prove to be useful for ecological and physiological studies.

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