TERTIARY SPECIATION MODELS IN AUSTRALIAN ANURANS: MOLECULAR DATA CHALLENGE PLEISTOCENE SCENARIO.

Abstract

Similarities between frogs in the faunas of southwestern and southeastern Australia have long been viewed as indicators of close genetic relationships and recent (Pleistocene) divergences. We studied albumin evolution in 16 east-west species pairs of frogs representing six genera to assess the validity of these conclusions. Analysis of albumin evolution in western species of Heleioporus and some species of Litoria suggested recent speciation in these genera, with the closest sister groups occurring in the western and not among the eastern fauna. All divergences measured between eastern and western cognate species point to a Tertiary separation extending from the late Miocene to the early Oligocene. Micro-complement fixation studies provide an independent estimation of both genetic relationships between species pairs and the time of divergence of each species pair, allowing the testing of models of speciation and vicariance biogeography in a way not possible with earlier methodologies.