Figure 1.
Divergence time estimates for Araucariaceae.
The topology presented is the maximum credibility tree (median node heights) obtained by pooling four separate runs under two constraint scenarios (see Table 1, and text for details). Circles indicate nodes that were included in the assessment of candidate nodal constraints, and the dark shaded circles indicate nodes that were constrained for the BRC analyses (see Table 1 for details). Node bars (nodes with a posterior probability ≥0.75) indicate the 95% HPD of divergence times for the two prior scenarios: left, log normal prior mean = minimum fossil age +50%; right, log normal prior mean = minimum fossil age +10% (NC, New Caledonia; NI, Norfolk Island).
Table 1.
Details of fossil constraints used to estimate araucarian divergence times (Prior 1, log normal prior mean = minimum fossil age +10%; Prior 2, log normal prior mean = minimum fossil age +50%) and empirical scaling factor (Si) estimates inferred from the unconstrained BRC analyses of the DNA sequences.
Figure 2.
Araucariaceae phylogeny inferred from plastid DNA sequences using Bayesian optimisation criteria (50% majority rule topology).
Support values, below the branch, are: ML bootstrap/Bayesian posterior probability. Branches marked with an asterisk have a BS of 100% and a PP of 1.0. Detail of the relationships among New Caledonian Araucaria is shown at the bottom left. Branch lengths are proportional to the inferred number of substitutions along that branch.
Figure 3.
Araucariaceae phylogeny inferred from ITS2 DNA sequences using Bayesian optimisation criteria (50% majority rule topology).
Support values are as detailed for Figure 2.
Figure 4.
Araucariaceae phylogeny inferred from a combined plastid and ITS2 DNA data set using Bayesian optimisation criteria (50% majority rule).
Support values are as detailed for Figure 2.
Figure 5.
Assessment of calibration constraints using empirical scaling factor (Si) estimates.
The mean (circle) and 95% highest posterior density interval (lines) of Si is shown for each proposed calibration, including: (a) alternative nodal placements of fossil Agathis and Araucaria (vertical boxes). In (a), the Si intervals are contrasted with the estimated age of conifers (c. 320 Ma; horizontal box). In (b), candidate fossils with Si estimates that consistently exceeded the maximum age of conifers have been removed. The grey shading indicates the region of overlap in Si intervals for the five retained calibrations.
Table 2.
Node age estimates (millions of years) for Araucariaceae estimated from the BRC analyses of DNA sequences (Prior 1, log normal prior mean = minimum fossil age +10%; Prior 2, log normal prior mean = minimum fossil age +50%).