Whooa. I find those little cylinders/discs all the time at a local river. Knew they were called crinoids. But never knew what a crinoid actually was. Assumed it was some sort of plant or something. Insanely cool.
They actually still exist today!!! They're just more commonly called sea lilies - relatives of sea stars, sea cucumbers, and sea urchins, they're very fascinating creatures. Most fossil crinoids were thought to be immobile, but we now have video proof that they can pull themselves out of the substrate and either swim or drag themselves to a new spot.
Not quite - they tend to have appendages to hold on to whatever they're living on but if they're disturbed by a predator or if they're not getting enough food they can detach themselves from whatever they're latches on and swim/drag away to a better spot
Most crinoids today dont have a stalk as adults but the stalked crinoids have it to get higher in the water column to feed/reproduce, so they have a small bit of appendages at the end of their stalk that is under the substrate if it's soft mud or it latches on to a rock. As because of how ocean currents work, just 3 feet up from the seafloor is way more productive than the seafloor itself.
Fossil crinoids have been found to have stems over 40 ft long.
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u/SharksForArms 2d ago
Whooa. I find those little cylinders/discs all the time at a local river. Knew they were called crinoids. But never knew what a crinoid actually was. Assumed it was some sort of plant or something. Insanely cool.