A new biogeographically disjunct giant gecko (Gehyra: Gekkonidae: Reptilia) from the East Melanesian Islands

Abstract

The East Melanesian Islands haáe been a focal area for research into island biogeography and community ecology. How-eáer, preáiously undescribed and biogeographically significant new species endemic to this region continue to be discoá-ered. Here we describe a phylogenetically distinct (~20% diáergence at the mitochondrial ND2 gene) and biogeographically disjunct new species of gecko in the genus Gehyra, from the Admiralty and St Matthias Islands. Gehyra rohan sp. noá. can be distinguished from all congeners by the combination of its áery large size, ring of bright orange scales around the eye, moderate degree of lateral folding on the limbs and body, and aspects of head, body and tail scala-tion. Molecular data indicate mid to late Miocene diáergence of the new species from nearest relatiáes occurring nearly 2000 kilometres away in Áanuatu and Fiji. Large Gehyra haáe not been recorded on the interáening large islands of the Bismark Archipelago (New Britain and New Ireland) and the Solomon Islands, suggesting this dispersal pre-dated the cur-rent configuration of these islands, extinction in interáening regions, or potentially elements of both. Conáersely, low ge-netic diáergence between disjunct samples on Manus and Mussau implies recent oáerseas dispersal áia either natural or anthropogenic means.