The Origin Of Varanus: When Fossils, Morphology, And Molecules Alone Are Never Enough

One of the many interesting questions in evolutionary studies of varanid lizards is the origin of the genus Varanus. The fossil record indicates the earliest emergence of this genus on Gondwana, although the remains of early varanid lizards have been discovered in Laurasia. The relationships among extant Varanus can generally be inferred using molecular phylogenetic techniques, although several attempts to generate a phylogeny of Varanus have used morphological characters. We identify two key-regions of global dispersal for varanid lizards that may be used to test hypotheses on the origin of this genus in a phylogeographic framework. The landmass currently connecting Africa and Asia as well as the Lesser Sunda Islands in southern Wallacea may have facilitated intercontinental radiation of varanid lizards, which are distributed in Africa, Asia, and Australia. We consider that an integrated approach such as phylogeography might better explain the origin of this charismatic lizard group than any single analytical method. Biawak, Vol. 4 No. 4. 2010. P: 117-124