Taphonomic comparison between Recent and fossil sand dollars

The taphonomy of a Recent and a fossil sand dollar are compared. The recent Echinodiscus auritus originates from a shallow-water carbonate environment in the Red Sea. The fossil Parascutella hِbarthi is found in micaceous sands of the Lower Miocene Austrian Molasse Zone. Both species show strong similarities in constructional morphology including the flattened overall shape, details of the surface morphology as well as the presence of an internal support system. Three taphonomic features are remarkable different: (1) lethal and non-lethal predation (especially high in the recent E. auritus; (2) encrustation of the test (especially by coralline algae in the fossil Parascutella); and (3) radial cracking on implosion of the body cavity caused by sediment loading on the fossil tests. Differences in taphonomic signatures can be correlated with depositional environment (predation and encrustation) as well as factors related to burial of the fossil specimens (sediment loading and diagenesis).