ORIGINAL ARTICLE Contrasting patterns of persistence and diversification in vicars of a widespread Australian lizard lineage (the Oedura marmorata complex) Paul M. Oliver 1,2 *, Katie L. Smith 2 , Rebecca J. Laver 1,2 , Paul Doughty 3 and Mark Adams 4,5 1 Department of Zoology, University of Melbourne, Parkville, VIC 3052, Australia, 2 Sciences Department, Museum Victoria, Melbourne, VIC 3001, Australia, 3 Department of Terrestrial Zoology, Western Australian Museum, Welshpool, Western Australia 6106, Australia, 4 Evolutionary Biology Unit, South Australian Museum, North Terrace, SA 5000, Australia, 5 School of Earth and Environmental Sciences, University of Adelaide, Adelaide, SA 5005,Australia *Correspondence: Paul Oliver, Department of Zoology, University of Melbourne, Parkville, VIC 3052, Australia. E-mail: paul.oliver@unimelb.edu.au ABSTRACT Aim Lineages in many parts of the world have distributions that have been shaped by range contraction in the face of deteriorating climatic conditions through the Neogene. When such lineages now consist of widely spaced vicari- ant populations (vicars) they provide opportunities (1) to compare and con- trast the timing and pattern of diversification within and between major geographical regions, and (2) to examine how differential interactions with geography, climate and localized adaptation may have shaped idiosyncratic pat- terns of genetic diversification. Location Australian Arid Zone (AAZ) and Australian Monsoonal Tropics (AMT). Methods We compiled and analysed mitochondrial DNA, nuclear DNA and allozyme datasets to determine the evolutionary history and genetic diversity of isolated populations of a gecko lineage (the Oedura marmorata complex and related taxa) distributed across the Australian monsoonal and arid biomes. Results Three widely allopatric lineages in the AAZ diverged during the late Miocene and Plio-Pleistocene. Populations in the AMT display much greater genetic turnover than those in the AAZ over equivalent geographical distances, and also include several lineages that are of equal or greater age than all diver- sity in the AAZ. Saxicoline lineages tend to show higher genetic diversity and/ or have more restricted ranges than arboreal relatives in both biomes. Main conclusions Lineages of Oedura show contrasting patterns of diversifi- cation in the two major biomes they inhabit. Diversity in the arid biome is younger and restricted to widely separated refugia, reflecting the younger age and pervasive harshness of this environment. Higher diversity in the AMT is also indicative of persistence, but at much finer geographical scales and broadly over a longer period of time, perhaps reflecting the more continuous spatial and temporal distribution of equitable habitats within this region. Finally, the wider distribution of arboreal lineages in both biomes suggests that ecological flexibility has also shaped the contrasting patterns of distribution in related lin- eages, and supports the contention that an association with rocks has shaped high lineage diversity in many taxa from the Australian Monsoonal Tropics. Keywords Arboreal, aridification, Australian Monsoonal Tropics, ecological diversification, evolutionary ecology, molecular phylogeny, palaeoclimatic change, phyloge- ography, saxicoline. ª 2014 John Wiley & Sons Ltd http://wileyonlinelibrary.com/journal/jbi 1 doi:10.1111/jbi.12364 Journal of Biogeography (J. Biogeogr.) (2014)