Permian crinoid ossicle fossil from Western Australia is 250-300 million years old. Brachiopods are commonly known as sea lilies and are marine echinoderms along with starfish and sea urchins.
The oldest known fossils are Ordovician 488MYA and the longest fossil stem is 40m.
Modern crinoids are the same as the ancient crinoids and their stem is an exoskeleton made of stacks of rings of calcium carbonate.
The center cavity of a crinoid may be elliptical, circular, pentagonal or star shaped. Some species have appendages at the base for anchoring. Crinoids use their arms, or brachials, to filter feed.
three specimens will be sent to show variation morphology.