Reptile diversity in the Houtman Abrolhos ArchipelagoCollection Highlights | Updated 1 decade ago Biogeography of the Abrolhos Islands Photo by Ric How The islands of the Houtman Abrolhos lie some 50 kilometres off the central WA coast near Geraldton. The islands provide an example of species populations that have been isolated for over 7000 years from their mainland relatives. The Abrolhos islands provide a unique natural laboratory to explore the genetic and morphological variation of species that have become isolated from each other for varying periods of time and by varying distances. On the two largest islands in the northern Wallabi Group reptile species have shown significant differences in the size and patterning of populations between this island and the larger adjacent West Wallabi island. Within the larger archipelago, individual islands have remained separated within by relatively deep sea channels, this isolation provides insights into the evolutionary patterns of reptiles and lizards where populations have been isolated over thousands of years.