The author acknowledges support for his recent work on these faunas from DFG grants La 1191/1-1 and -2. This article was partly inspired by participation in meetings on evolutionary change: Geoscience 2000, Manchester; Geological Society London Lyell meeting, 2001; NAPC Berkeley, 2001; The author wishes to thank these meetings' organisers, fellow participants, and the DFG for travel support for attending the NAPC. A. Mackensen (AWI, Bremerhaven) generously provided computer readable versions of his data for use in this study. B. Mohr, D. Unwin and M. Apel are thanked for discussions which assisted the writing of this article and two anonymous reviewers for suggestions on how to improve it.