Evidence that ebolaviruses and cuevaviruses have been diverging from marburgviruses since the Miocene.

An understanding of the timescale of evolution is critical for comparative virology but remains elusive for many RNA viruses. Age estimates based on mutation rates can severely underestimate divergences for ancient viral genes that are evolving under strong purifying selection. Paleoviral dating, however, can provide minimum age estimates for ancient divergence, but few orthologous paleoviruses are known within clades of extant viruses.