Figure 3

Fossil taxa relied upon for molecular clock calibrations may produce highly spurious dates if their phylogenetic position is not precisely known. In this example, an early fossil taxon attributed simply to 'Bovini' might be assumed to be close to the most recent common ancestor of the living bovins (point 1, node of origin of crown Bovini as defined by the most recent common ancestor of Bos taurus and Bubalus bubalis) when in fact it may be a stem bovin of much older age (point 2).