This pattern of divergence is best explained by a model where 92% of bee lineages died out 65 million years ago, and the few remaining species rapidly diverged soon afterwards.
I like to think of this as good news. If we can halt the current decimation of our modern honeybees, maybe they too can bounce back from the brink. Of course, it might take a few million years.Sandra M. Rehan, Remko Leys, & Michael P. Schwarz (2013). First Evidence for a Massive Extinction Event Affecting Bees Close to the K-T Boundary PloS ONE DOI: 10.1371/journal.pone.0076683.