A Silurian crinoid thanatotope from Gotland

The ‘När block’ (approximately 1 × 1 m) from the Silurian (Ludlovian) Eke Beds of Gotland, Sweden, displays a crinoid thanatotope of 260 specimens belonging to four species, Haereticotaxocrinus asper n. gen., n. sp., Desmidocrinus pentadactylus Angelin, Carpocrinus petilus n. sp., and C. angelini n. sp. They occur in marked preferred orientation at the upper surface of a lens consisting of Coenites fragments and bioclastic debris, and were buried in situ by a sudden influx of the same type of sediment. The fossilizable community comprized crinoids only: those other organisms occurring in the rock, including the ubiquitous Coenites, were washed in with the sediment burying the crinoids and were no part of the community itself. Crinoid stem lengths indicate a multi-level community pattern, with Haereticotaxocrinus forming the upper crinoid level. The Carpocrinus and Haereticotaxocrinus populations include juvenile specimens, while Desmidocrinus comprises adults only. Echinodertmata, Crinoidea, new genus, new species, Haereticotaxocrinus asper, Carpocrinus angelini, Carpocrinus petilus, Desmidocrinus pentadactylus, ecology, Eke Beds, Silurian, Gotland, Sweden.