Figureȱ1.ȱMountainsȱofȱNewȱGuineaȱ(fig.ȱ1ȱinȱDiamondȱ&ȱBishopȱ2021b).ȱTheȱCentralȱRangeȱisȱcross-hatched.ȱ In solid black and named are ten outlying mountain ranges, detached from the Central Range and rising from the lowlands along New Guinea's north and north-west coasts. One of those ten ranges, the Cyclops Mts., is the subject of this paper. During Pleistocene cold phases of low sea level, the current Arafura Sea was a large exposed platform joining southern New Guinea and its Fly River bulge to northern Australia. The Aru Islands remain above sea level today, as a surviving modern fragment of that platform. Similarly, Yapen Island remains above sea level as a surviving modern fragment of a platform exposed during the Pleistocene offȱnorth-westȱNewȱGuinea. in Why are New Guinea's Cyclops Mountains poor in upland bird species?