Two new microhylid frog species of the genus Xenorhina Peters, 1863 from the Raja Ampat Islands, Indonesia

Two new species of the asterophryine microhylid genus Xenorhina are described from the Raja Ampat archipelago off the western tip of New Guinea. Both are medium-sized (snout-urostyle length 29.9 – 35.2 and 28.5 – 39.5 mm), semi-fossorial frogs that call from hidden positions within the litter or under the soil surface. The two new species are morphologically similar but they have different advertisement calls. Although they are probably closely related, genetic studies are required to confirm this. The first species is known only from Salawati Island, a land-bridge island that was connected to the New Guinea mainland during the last glacial period. The second species is currently known only from Waigeo Island, an oceanic island long isolated from New Guinea that is separated from nearby Salawati by a major biogeographic barrier, the narrow but deep Sagewin Strait. Description of these two species appears to be another example of differentiation across this barrier, and brings the total number of Xenorhina known from New Guinea and surrounding islands to 34