Data from: An ancient origin for the enigmatic Flat-Headed Frogs (Bombinatoridae: Barbourula) from the islands of Southeast Asia
Data files
Aug 27, 2010 version files 138.58 KB
Abstract
Background: The complex history of Southeast Asian islands has long been of interest to biogeographers. Dispersal and
vicariance events in the Pleistocene have received the most attention, though recent studies suggest a potentially more
ancient history to components of the terrestrial fauna. Among this fauna is the enigmatic archaeobatrachian frog genus
Barbourula, which only occurs on the islands of Borneo and Palawan. We utilize this lineage to gain unique insight into the
temporal history of lineage diversification in Southeast Asian islands.
Methodology/Principal Findings: Using mitochondrial and nuclear genetic data, multiple fossil calibration points, and
likelihood and Bayesian methods, we estimate phylogenetic relationships and divergence times for Barbourula. We determine
the sensitivity of focal divergence times to specific calibration points by jackknife approach in which each calibration point is
excluded from analysis. We find that relevant divergence time estimates are robust to the exclusion of specific calibration
points. Barbourula is recovered as a monophyletic lineage nested within a monophyletic Costata. Barbourula diverged from its
sister taxon Bombina in the Paleogene and the two species of Barbourula diverged in the Late Miocene.
Conclusions/Significance: The divergences within Barbourula and between it and Bombina are surprisingly old and
represent the oldest estimates for a cladogenetic event resulting in living taxa endemic to Southeast Asian islands.
Moreover, these divergence time estimates are consistent with a new biogeographic scenario: the Palawan Ark Hypothesis.
We suggest that components of Palawan’s terrestrial fauna might have ‘‘rafted’’ on emergent portions of the North Palawan
Block during its migration from the Asian mainland to its present-day position near Borneo. Further, dispersal from Palawan
to Borneo (rather than Borneo to Palawan) may explain the current day disjunct distribution of this ancient lineage.