Not that young: combining plastid phylogenomic, plate tectonic and fossil evidence indicates a Palaeogene diversification of Cycadaceae

A 2011 fossil-calibrated molecular analysis inferred that most sampled living cycad species originated within roughly the preceding 12 million years, but later fossil-integrated work weakens a simple globally synchronous-radiation narrative; none of these models dates the origin or fossil first appearance of Cycadales.

Under a calibration scheme combining a Cycas fossil, Palawan tectonic history and plastome data, different tree priors yielded mean crown ages of extant Cycadaceae of approximately 69.31 and 42.88 Ma; this Palaeogene-to-Late-Cretaceous model result is not a fossil first appearance for Cycadaceae or an age for all cycads.