Llandovery (early Silurian) crinoids from Hiiumaa Island, western Estonia

Abstract

AbstractRhuddanian crinoid faunas are poorly known globally, making this new fauna from the Hilliste Formation of western Estonian especially significant. The Hilliste fauna is the oldest Silurian fauna known from the Baltica paleocontinent, thus this is the first example of the crinoid recovery fauna after the Late Ordovician mass extinction. Hiiumaacrinus vinni n. gen. n. sp., Protaxocrinus estoniensis n. sp., Eomyelodactylus sp., calceocrinids, and five holdfast types are reported here. Although the fauna has relatively few taxa, it is among the most diverse Rhuddanian faunas known. Similar to other Rhuddanian crinoid faunas elsewhere, the Hilliste crinoid fauna contains crinoids belonging the Dimerocrinitidae, Taxocrinidae, Calceocrinidae, and Myelodactylidae; most elements of the new fauna are quite small, perhaps indicative of the Lilliput Effect.