title: An Ancient Divide in a Contiguous Rainforest: Endemic Earthworms in the Australian Wet Tropics.
abstract: Understanding the factors that shape current species diversity is a fundamental aim of ecology and evolutionary biology. The Australian Wet Tropics (AWT) are a system in which much is known about how the rainforests and the rainforest-dependent organisms reacted to late Pleistocene climate changes, but less is known about how events deeper in time shaped speciation and extinction in this highly endemic biota. We estimate the phylogeny of a species-rich endemic genus of earthworms (Terrisswalkerius) from the region. Using DEC and DIVA historical biogeography methods we find a strong signal of vicariance among known biogeographical sub-regions across the whole phylogeny, congruent with the phylogeography of less diverse vertebrate groups. Absolute dating estimates, in conjunction with relative ages of major biogeographic disjunctions across Australia, indicate that diversification in Terrisswalkerius dates back before the mid-Miocene shift towards aridification, into the Paleogene era of isolation of mesothermal Gondwanan Australia. For the Queensland endemic Terrisswalkerius earthworms, the AWT have acted as both a museum of biological diversity and as the setting for continuing geographically structured diversification. These results suggest that past events affecting organismal diversification can be concordant across phylogeographic to phylogenetic levels and emphasize the value of multi-scale analysis, from intra- to interspecies, for understanding the broad-scale processes that have shaped geographic diversity.
authors.affiliation: Field Museum of Natural History, Department of Science and Education, 1400 South Lake Shore Drive, Chicago, Illinois 60605, United States of America.
authors.forename: Corrie S
authors.initials: CS
authors.lastname: Moreau
authors.affiliation: Museum Victoria, GPO Box 666, Melbourne, VIC 3001, Australia.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Hugall
authors.affiliation: Queensland Parks and Wildlife Service, Northern Region, Atherton, QLD 4883, Australia.
authors.forename: Keith R
authors.initials: KR
authors.lastname: McDonald
authors.affiliation: University of Queensland, School of Biological Sciences, Brisbane, QLD 4072, Australia.
authors.forename: Barrie G M
authors.initials: BG
authors.lastname: Jamieson
authors.affiliation: Australian National University, Research School of Biology & Center for Biodiversity Analysis, Canberra, ACT 2601, Australia.
authors.forename: Craig
authors.initials: C
authors.lastname: Moritz
mesh_terms: D000818:Animals; D001315:Australia; D005075:Biological Evolution; D009835:Oligochaeta / Q000235:genetics / Q000502:physiology*; D058974:Phylogeography; D065947:Rainforest; D014329:Tropical Climate