Young relicts and old relicts: a novel palaeoendemic vertebrate from the Australian Central Uplands

Abstract

Climatic change, and in particular aridification, has played a dominant role in shaping Southern Hemisphere biotas since the mid-Neogene. In Australia, ancient and geologically stable ranges within the vast arid zone have functioned as refugia for populations of mesic taxa extirpated from surrounding areas, yet the extent to which relicts may be linked to major aridification events before or after the Pliocene has not been examined in detail. Here we use molecular phylogenetic and morphological data to show that isolated populations of saxicoline geckos in the genus Oedura from the Australian Central Uplands, formerly confounded as a single taxon, actually comprise two divergent species with contrasting histories of isolation. The recently resurrected Oedura cincta has close relatives occurring elsewhere in the Australian arid biomes with estimated divergence dates concentrated in the early Pliocene. A new taxon (described herein) diverged from all extant Oedura much earlier, well before the end of the Miocene. A review of data for Central Uplands endemic vertebrates shows that for most (including Oedura cincta), gene flow with other parts of Australia probably occurred until at least the very late Miocene or Pliocene. There are, however, a small number of palaeoendemic taxa—often ecologically specialized forms—that show evidence of having persisted since earlier intensification of aridity in the late Miocene.

Habitat as a mediator of mesopredator‐driven mammal extinction

“…Irrespective of the mechanisms underpinning differences in extirpation and extinction across habitat types, our results highlight the importance of large areas of rugged terrain—some of which are already identified as significant evolutionary refugia (Pepper et al. ; Oliver & McDonald )—as refuges for CWR mammals. Although it is unclear whether other mountain systems in Australia's drylands share the refuge characteristics of the MacDonnell Ranges, there is evidence that rugged regions of northern Australia have also protected CWR mammals.…”

Contrasting scales of local persistence between monsoonal and arid biomes in closely related, low‐dispersal vertebrates

“…northern Top End) could have been much less affected by the LGM (Potter et al, ). For the AZ, the obvious major refugia are the ancient rocky ranges and plateaus of the Pilbara craton in the west and the Central Ranges in the inland (Figure ; Oliver & McDonald, ; Pepper, Doughty, & Keogh, ; Pepper, Fujita, Moritz, & Keogh, ; Pepper, Ho, Fujita, & Keogh, ). For the MT, major refugia occur in the dissected sandstone plateaus and ranges in the Top End and Kimberley (Potter, Eldridge, Taggart, & Cooper, ; Potter et al, ), as well as karst limestones at the interface of the AZ and MT (Oliver et al, ).…”

Origins and patterns of endemic diversity in two specialized lizard lineages from the Australian Monsoonal Tropics (Oedura spp.)

“…Velvet geckos ( Oedura ) are a lineage of scansorial (i.e. climbing specialist; including arboreal and saxicoline taxa) lizards widespread across tropical and arid Australia that show strong evidence of long‐term localized persistence through climatic change (Oliver, Laver, Melville, & Doughty, ; Oliver & McDonald, ; Oliver, Smith, Laver, Doughty, & Adams, ). In the Kimberley, there are two endemic distantly related clades of Oedura (Oliver, Smith, et al., ) with broadly overlapping distributions: (1) a restricted clade of two allopatric species in the west Kimberley – O. filicipoda and the recently described O. murrumanu , hereafter referred to as the filicipoda species‐group, and (2) the widespread O. gracilis complex.…”