The last shallow-water stem crinoids

Recent stalked crinoids exclusively live at considerable depths, but in the geological past they were common in shallow-marine environments. It has been argued that predatory pressure at the end of the Mesozoic and early Paleogene, associated with the so-called Mesozoic Marine Revolution, may have contributed to the disappearance of stalked crinoids from shallow-sea environments. The youngest occurrence of shallow-sea stalked crinoids (isocrinids) has been described from the Miocene sediments of Poland. This discovery suggests that the migration of this group of crinoids to deep-sea environments was not synchronous on a global scale.