New Guinea uplift opens ecological opportunity across a continent

Area of Science:

• Evolutionary biology
• Biogeography
• Geology

Background:

• Sahul, comprising New Guinea and Australia, features dynamic environments.
• New Guinea's geological uplift is hypothesized to drive species diversification.
• The biogeographic impact of this uplift across Sahul remains largely untested.

Purpose of the Study:

• Reconstruct the assembly of a rodent radiation (Murinae: Hydromyini) across Sahul.
• Investigate the role of geological uplift and colonization in diversification.
• Test the hypothesis of New Guinea's orogeny as a species pump.

Main Methods:

• Phylogenomic analysis of 270 rodent specimens.
• Inclusion of extinct and elusive species.
• Reconstruction of geographic and biome transitions.

Main Results:

• A single over-water colonization from Asia around 8.5 million years ago.
• Ancestral rodents were confined to proto-New Guinea for 3.5 million years.
• Diversification accelerated around 5 million years ago, coinciding with New Guinea's orogeny and Australian colonization.
• Frequent transitions between regions and biomes were observed.
• Recurrent over-water colonization between mainland and islands played a significant role.

Conclusions:

• New Guinea's geological uplift created ecological opportunities, driving diversification across Sahul.
• Sustained diversification was facilitated by over-water colonization from the Pleistocene to the present.
• Geological processes, biome shifts, and island colonization collectively shaped this continental radiation.