A Tale of Two Crinoids

A stalked crinoid, from the Permian, and a living one, from Sumilon island, Philippines, a mobile form which climbed onto a whip coral (the long “wire”. Crinoids are echinoderms, like sea urchins and seastars, and feed by filtering the seawater.

The fossil rests in the natural history museum in Vienna. The majority of stalked crinoids died out in the mass extinction at the end of the Permian. The extant crinoid leaned to use another organism as a “stalk”. Even in crinoids, behavior is a major factor in evolution.

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