title: Unveiling the diversification dynamics of Australasian predaceous diving beetles in the Cenozoic.
abstract: During the Cenozoic, Australia experienced major climatic shifts that have had dramatic ecological consequences for the modern biota. Mesic tropical ecosystems were progressively restricted to the coasts and replaced by arid-adapted floral and faunal communities. Whilst the role of aridification has been investigated in a wide range of terrestrial lineages, the response of freshwater clades remains poorly investigated. To gain insights into the diversification processes underlying a freshwater radiation, we studied the evolutionary history of the Australasian predaceous diving beetles of the tribe Hydroporini (147 described species). We used an integrative approach including the latest methods in phylogenetics, divergence time estimation, ancestral character state reconstruction, and likelihood-based methods of diversification rate estimation. Phylogenies and dating analyses were reconstructed with molecular data from seven genes (mitochondrial and nuclear) for 117 species (plus 12 outgroups). Robust and well-resolved phylogenies indicate a late Oligocene origin of Australasian Hydroporini. Biogeographic analyses suggest an origin in the East Coast region of Australia, and a dynamic biogeographic scenario implying dispersal events. The group successfully colonized the tropical coastal regions carved by a rampant desertification, and also colonized groundwater ecosystems in Central Australia. Diversification rate analyses suggest that the ongoing aridification of Australia initiated in the Miocene contributed to a major wave of extinctions since the late Pliocene probably attributable to an increasing aridity, range contractions and seasonally disruptions resulting from Quaternary climatic changes. When comparing subterranean and epigean genera, our results show that contrasting mechanisms drove their diversification and therefore current diversity pattern. The Australasian Hydroporini radiation reflects a combination of processes that promoted both diversification, resulting from new ecological opportunities driven by initial aridification, and a subsequent loss of mesic adapted diversity due to increasing aridity.
authors.affiliation: SNSB-Bavarian State Collection of Zoology, Münchhausenstraße 21, 81247 Munich, Germany; CNRS, UMR 7641 Centre de Mathématiques Appliquées (Ecole Polytechnique), Route de Saclay, 91128 Palaiseau cedex, France; South Australian Museum, Adelaide, South Australia, Australia; Centre for Integrated Ecology & School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia; and GeoBioCenter, Ludwig-Maximilians University, Munich, Germany. Toussaint@zsm.mwn.de.
authors.forename: Emmanuel F A
authors.initials: EF
authors.lastname: Toussaint
authors.affiliation: SNSB-Bavarian State Collection of Zoology, Münchhausenstraße 21, 81247 Munich, Germany; CNRS, UMR 7641 Centre de Mathématiques Appliquées (Ecole Polytechnique), Route de Saclay, 91128 Palaiseau cedex, France; South Australian Museum, Adelaide, South Australia, Australia; Centre for Integrated Ecology & School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia; and GeoBioCenter, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Fabien L
authors.initials: FL
authors.lastname: Condamine
authors.affiliation: SNSB-Bavarian State Collection of Zoology, Münchhausenstraße 21, 81247 Munich, Germany; CNRS, UMR 7641 Centre de Mathématiques Appliquées (Ecole Polytechnique), Route de Saclay, 91128 Palaiseau cedex, France; South Australian Museum, Adelaide, South Australia, Australia; Centre for Integrated Ecology & School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia; and GeoBioCenter, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Hawlitschek
authors.affiliation: SNSB-Bavarian State Collection of Zoology, Münchhausenstraße 21, 81247 Munich, Germany; CNRS, UMR 7641 Centre de Mathématiques Appliquées (Ecole Polytechnique), Route de Saclay, 91128 Palaiseau cedex, France; South Australian Museum, Adelaide, South Australia, Australia; Centre for Integrated Ecology & School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia; and GeoBioCenter, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Chris H
authors.initials: CH
authors.lastname: Watts
authors.affiliation: SNSB-Bavarian State Collection of Zoology, Münchhausenstraße 21, 81247 Munich, Germany; CNRS, UMR 7641 Centre de Mathématiques Appliquées (Ecole Polytechnique), Route de Saclay, 91128 Palaiseau cedex, France; South Australian Museum, Adelaide, South Australia, Australia; Centre for Integrated Ecology & School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia; and GeoBioCenter, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Nick
authors.initials: N
authors.lastname: Porch
authors.affiliation: SNSB-Bavarian State Collection of Zoology, Münchhausenstraße 21, 81247 Munich, Germany; CNRS, UMR 7641 Centre de Mathématiques Appliquées (Ecole Polytechnique), Route de Saclay, 91128 Palaiseau cedex, France; South Australian Museum, Adelaide, South Australia, Australia; Centre for Integrated Ecology & School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia; and GeoBioCenter, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Hendrich
authors.affiliation: SNSB-Bavarian State Collection of Zoology, Münchhausenstraße 21, 81247 Munich, Germany; CNRS, UMR 7641 Centre de Mathématiques Appliquées (Ecole Polytechnique), Route de Saclay, 91128 Palaiseau cedex, France; South Australian Museum, Adelaide, South Australia, Australia; Centre for Integrated Ecology & School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia; and GeoBioCenter, Ludwig-Maximilians University, Munich, Germany. SNSB-Bavarian State Collection of Zoology, Münchhausenstraße 21, 81247 Munich, Germany; CNRS, UMR 7641 Centre de Mathématiques Appliquées (Ecole Polytechnique), Route de Saclay, 91128 Palaiseau cedex, France; South Australian Museum, Adelaide, South Australia, Australia; Centre for Integrated Ecology & School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia; and GeoBioCenter, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Balke
mesh_terms: D000818:Animals; D001315:Australia; D001517:Coleoptera / Q000145:classification* / Q000235:genetics; D005580:Fossils; D017344:Genes, Insect / Q000235:genetics; D049810:Genetic Speciation; D014644:Genetic Variation; D010802:Phylogeny
keywords: Australian aridification; Dytiscidae; Hydroporini; Pleistocene extinction; diversification; freshwater biota; ground water organisms