It has been brought to our attention that we made an error in the date that we reported for the Kupferschiefer. We stated in the text that Brauns et al. [1]: "reported a date of 257.3±2.6 Ma (Late Permian/Lopingian: Wuchiapingian) for the Kupferschiefer based on a Re-Os geochronological study." However, in actual fact the date reported by Brauns et al. [1] was 257.3±1.6 Ma (Late Permian/Lopingian: Wuchiapingian).

Although this error has no impact on the vast majority of the conclusions of the paper, it does mean that our recommended minimum fossil calibration date for the crocodile-lizard split of 254.7 Ma is incorrect, and should in fact be 255.7 Ma.

We have contacted PLoS ONE to request that an erratum be published, but wish to make readers aware of this error in the meantime.

Richard Butler (on behalf of all the authors)

Reference:

1. Brauns CM, Pätzold T, Haack U (2003) A Re–Os study bearing on the age of the Kupferschiefer at Sangerhausen (Germany). Utrecht: Abstracts XVth Intern Congress on Carboniferous and Permian Stratigraphy. p. 66.