Class Psammocorallia (Coelenterata, Vendian‐Ordovician): Recognition, systematics, and distribution

Evidence from the Lower Cambrian of Sweden and Mongolia and the Ordovician of Jordan shows the body fossil nature of Protolyellia and Spatangopsis. This interpretation is tentatively extended to the Vendían Beltanelliformis/Nemiana. Systematically the Class Psammocorallia comprises Protolyellia princeps Torell, P. benderi (Huckriede), P. simplex (Palij), and Spatangopsis costata Torell, S. alata n.sp., S. mongolica n.sp., and S. scotica n. sp. Brooksella cambria is interpreted as a trace fossil reminiscent of Asterosoma. Similarly shaped sand volcanoes ('Astropolithon') owe their medusoid morphology to interference with biomats.