Early Silurian crinoid diversification on Baltica: Euspirocrinus varbolaensis sp. nov.

This article describes the crinoid Euspirocrinus varbolaensis sp. nov. from the early Silurian (Rhuddanian) of northern Estonia. Discovered within the lower Rhuddanian strata in the Reinu quarry, Rapla Parish, this is the second Rhuddanian species of Euspirocrinus from Estonia. Its discovery further documents the rapid faunal recovery of early Silurian crinoids following the Late Ordovician biotic crisis. This find supports the hypothesis that the early Silurian recovery of crinoids was primarily the result of the diversification and migration of Laurentian clades.