Data from: Tectonic collision and uplift of Wallacea triggered the global songbird radiation

Songbirds (oscine passerines) are the most species rich and cosmopolitan
bird group, comprising almost half of global avian species diversity.
Because of their diversity and ubiquity, songbirds are used extensively in
studies of evolutionary ecology, diversification, and ethology. Songbirds
originated in Australia, but the evolutionary trajectory from a single
species in an isolated continent to worldwide proliferation is poorly
understood. Prior research suggested songbird diversification scenarios
that are largely uncoupled from Earth history, including extensive
diversification of lineages in New Guinea prior to its emergence as a
landmass and long-distance dispersal to Africa or Asia when no dispersal
corridors existed. However, these results may be flawed because the
studies relied on unresolved phylogenetic relationships and a
controversial biogeographic time calibration. Here, we combine the first
genome-scale DNA sequence data set for songbirds, fossil-based time
calibrations, and geologically informed biogeographic reconstructions to
provide the first well-supported evolutionary hypothesis for the group. We
show that songbird diversification began in the Oligocene, but accelerated
in the early Miocene, at approximately half the age of most previous
estimates. This burst of diversification occurred after island formation
in Wallacea, which provided the first dispersal corridor out of Australia,
and resulted in independent waves of songbird expansion through Asia to
the rest of the globe. Although New Guinea presently contains high
songbird species richness, our data unambiguously falsify the proto-Papuan
hypothesis for early songbird diversification and suggest that New Guinea
has, instead, served as an “evolutionary refuge” for Australian lineages
that have diversified more recently within the island. Our results
reconcile songbird evolution with Earth history and link a major radiation
of terrestrial biodiversity to early diversification within an isolated
Australian continent.