title: Post-Eocene climate change across continental Australia and the diversification of Australasian spiny trapdoor spiders (Idiopidae: Arbanitinae).
abstract: The formation and spread of the Australian arid zone during the Neogene was a profoundly transformative event in the biogeographic history of Australia, resulting in extinction or range contraction in lineages adapted to mesic habitats, as well as diversification and range expansion in arid-adapted taxa (most of which evolved from mesic ancestors). However, the geographic origins of the arid zone biota are still relatively poorly understood, especially among highly diverse invertebrate lineages, many of which are themselves poorly documented at the species level. Spiny trapdoor spiders (Idiopidae: Arbanitinae) are one such lineage, having mesic 'on-the-continent' Gondwanan origins, while also having experienced major arid zone radiations in select clades. In this study, we present new orthologous nuclear markers for the phylogenetic inference of mygalomorph spiders, and use them to infer the phylogeny of Australasian Idiopidae with a 12-gene parallel tagged amplicon next-generation sequencing approach. We use these data to test the mode and timing of diversification of arid-adapted idiopid lineages across mainland Australia, and employ a continent-wide sampling of the fauna's phylogenetic and geographic diversity to facilitate ancestral area inference. We further explore the evolution of phenotypic and behavioural characters associated with both arid and mesic environments, and test an 'out of south-western Australia' hypothesis for the origin of arid zone clades. Three lineages of Idiopidae are shown to have diversified in the arid zone during the Miocene, one (genus Euoplos) exclusively in Western Australia. Arid zone Blakistonia likely had their origins in South Australia, whereas in the most widespread genus Aganippe, a more complex scenario is evident, with likely range expansion from southern Western Australia to southern South Australia, from where the bulk of the arid zone fauna then originated. In Aganippe, remarkable adaptations to phragmotic burrow-plugging in transitional arid zone taxa have evolved twice independently in Western Australia, while in Misgolas and Cataxia, burrow door-building behaviours have likely been independently lost at least three times in the eastern Australian mesic zone. We also show that the presence of idiopids in New Zealand (Cantuaria) is likely to be the result of recent dispersal from Australia, rather than ancient continental vicariance. By providing the first comprehensive, continental synopsis of arid zone biogeography in an Australian arachnid lineage, we show that the diversification of arbanitine Idiopidae was intimately associated with climate shifts during the Neogene, resulting in multiple Mio-Pliocene radiations.
authors.affiliation: Biodiversity and Geosciences Program, Queensland Museum, South Brisbane, QLD 4101, Australia; Australian Centre for Evolutionary Biology and Biodiversity, and Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia; Department of Terrestrial Zoology, Western Australian Museum, Welshpool, WA 6106, Australia. Electronic address: michael.rix@qm.qld.gov.au.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Rix
authors.affiliation: Evolutionary Biology Unit, South Australian Museum, Adelaide, SA 5005, Australia; Australian Centre for Evolutionary Biology and Biodiversity, and Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Steven J B
authors.initials: SJB
authors.lastname: Cooper
authors.affiliation: Institute for Biology I (Zoology), Department of Evolutionary Biology and Ecology, University of Freiburg, D-79104 Freiburg (Brsg.), Germany; Australian National Insect Collection, CSIRO National Research Collections Australia, Acton, ACT 2601, Australia; Zoological Researchmuseum Alexander Koenig, Centre for Molecular Biodiversity, D-53113 Bonn, Germany.
authors.forename: Karen
authors.initials: K
authors.lastname: Meusemann
authors.affiliation: Department of Bioinformatics and Genetics, Swedish Museum of Natural History, SE-104 05 Stockholm, Sweden; Natural History Museum, Department of Invertebrates, CH-3005 Bern, Switzerland; Australian Centre for Evolutionary Biology and Biodiversity, and Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Seraina
authors.initials: S
authors.lastname: Klopfstein
authors.affiliation: Australian Centre for Evolutionary Biology and Biodiversity, and Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Sophie E
authors.initials: SE
authors.lastname: Harrison
authors.affiliation: Department of Terrestrial Zoology, Western Australian Museum, Welshpool, WA 6106, Australia.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Harvey
authors.affiliation: Australian Centre for Evolutionary Biology and Biodiversity, and Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Austin
mesh_terms: D000818:Animals; D001315:Australia; D005075:Biological Evolution; D057231:Climate Change; D017753:Ecosystem; D049810:Genetic Speciation; D009520:New Zealand; D010802:Phylogeny; D013021:South Australia; D013112:Spiders / Q000145:classification / Q000235:genetics*; D014904:Western Australia
keywords: Araneae; Domiothelina; Illumina; Mygalomorphae; NGS; Systematics