Phylogeny, taxonomy and biogeography of a circum-Indian Ocean clade of leaf-toed geckos (Reptilia: Gekkota), with a description of two new genera

<div><p>Geckos with a leaf-toed morphology (digits with a single pair of enlarged adhesive pads located terminally) occur on six continents and many islands. Although most leaf-toed gecko genera belong to independently derived lineages, recent studies support the monophyly of a circum-Indian Ocean group including four genera from disparate regions: the southern African genera <i>Afrogecko</i> and <i>Cryptactites</i>, the Malagasy genus <i>Matoatoa</i>, and the Australian genus <i>Christinus</i>. We obtained molecular and/or morphological data for most species in these genera to estimate phylogenetic relationships among constituent species and infer broad historical biogeographic patterns. Our results confirm that <i>Afrogecko</i> is not monophyletic, and that <i>Christinus</i> is embedded among African taxa. <i>Afrogecko</i> is comprised of three lineages, each of which is distinct in external features and osteology. Based on these results, we partition <i>Afrogecko</i> and recognize two new genera. Molecular clock analyses suggest divergences within the circum-Indian Ocean group are too recent for Gondwanan vicariance or hypothesized land bridges (e.g. Kerguelen Plateau) to account for the observed Africa/Madagascar/Australia distributional pattern. Ancestral area analyses support an origin of the clade in mainland Africa or Madagascar, and imply a dispersal event from southern Africa to Australia, similar to those observed in some plant and arthropod taxa, but otherwise unknown among non-volant terrestrial vertebrates. Dispersal was likely via a southern route and may have been facilitated by island hopping using Antarctica or other southern landmasses available in the mid-Cainozoic.</p><p><a href="http://zoobank.org/urn:lsid:zoobank.org:pub:7706B624-CD49-45CC-9DA3-FAB370BEE12B)." target="_blank">http://zoobank.org/urn:lsid:zoobank.org:pub:7706B624-CD49-45CC-9DA3-FAB370BEE12B).</a></p></div>