Palaeoecology and taphonomy of a Seirocrinus (Echinodermata: Crinoidea) colony from the Early Jurassic Posidonienschiefer Formation (Early Toarcian) of Dotternhausen (SW Germany)

A completely preserved colony of Seirocrinus is described and statistically interpreted. There is no correlation between stem length and crown size of individual crinoids. Additionally, a highly variable population density of Seirocrinus individuals alongside the driftwood is documented. A colonisation scenario of the driftwood over time is introduced and a four generation colonisation is proposed. The possible reproduction cycle of Seirocrinus is discussed in relation to palaeogeography and palaeoclimate. Different types of driftwood and their difference in floating time capability are discussed. The taphonomy of a triple stack of Seirocrinus specimens preserved in three subsequent layers one above the other is described and their impact on the interpretation of the bottom water flow in the Posidoniashale Sea, which is supposed to be towards the Belford Gap, is discussed.