Methodology: Genus age estimate

Gather (data collection took place in 2005-2006): - All occurrences by genus from PBDB - Age of genus origination from Sepkoski (database), Veron (book), and Wells (Treatise).

Reach a consensus age estimate. - Enter oldest known occurrences into PBDB from primary sources. - Use the oldest age that could be substantially verified with primary literature. - Dubious / outlier first occurrences from the PBDB were not typically considered the first occurrence of the genus. - No attempt was made to re-identify or verify the taxonomy of the published literature.