Time-calibrated phylogeny (X-axis in millions of years) and biogeographic reconstructions for the four-area Gondwanan model for Notothenioidei. The constrained maximum-likelihood biogeographic model included four areas corresponding to Gondwanan landmasses. New Zealand (black), Australia, (red), South America (blue) and Antarctica (light blue). The ancestral range shown at each internal node (colored boxes) are the reconstructed scenarios with the highest composite Akaike weight obtain analysis conducted on 1000 randomly chosen phylogenies from the posterior distribution of the Bayesian inferred time trees. The scenarios are drawn to reflect the splitting of the ancestral range due to the speciation event: the colored boxes to the left of the split (black line) represent the range inherited by the upper branch, with the colored boxes to the right of the split represent the range inherited by the lower branch. The timing of major paleogeographic events associated with the fragmentation of the Weddellian Province and East Gondwana are indicated along the x-axis.