Age estimates of Xylocopinae root age and tribe origins obtained from a relaxed clock model.

The root node, connecting the corbiculate outgroup with the Xylocopinae, was set at four different values, ranging from 90 Mya to 120 Mya to explore the effects on internal node estimates. The root node age set to 107 Mya corresponds to the estimate by Cardinal and Danforth [7]. Age estimates are also given for the node uniting Manueliini, Ceratinini and Allodapini (M+C+A), the node uniting the Ceratinini and Allodapini (C+A), and the most recent common ancestor (MRCA) for the two allodapine species (Exoneurella tridentata and Hasinamelissa minuta) that have true worker castes. Bayesian analyses indicate that this MRCA did not have true castes, so that the age of this node predates the two origins of true workers. Node age estimates are also given in parentheses for a penalized likelihood transformation of the consensus phylogram obtained from a MrBayes analysis where the root node was set to 107 Mya.