What is a crinoid?

Crinoid is a sea animal class Crinoidea. There is only one existing subclass of Crinoids, Articulata, consisting of 540 species described, although other subclass once existed, but now they are extinct. Criminals, also called marine lilies or feathers-stars, are grim or barbed invertebrate consisting of a series of weapons around the central upper mouth. They can be attached to a substrate or free broth, and some types of crinoids have both forms at different stages of life cycle.

Crinoid species are quite diverse, although not as abundant as they used to be. Dryned crinoid species are known from fossils from the paleozoic era. Today, Crinoids can live in very shallow waters or depths of up to four kilometers (six kilometers). Crinoids also differ in appearance, although many of them are colorful and resemble flowers.

Crinoid consists of three basic parts of the body: chalice, arm and stem. Calyx consists of digestion and reproductive systems and is surrounded by weaponsor brachials. Brachials usually follow five times symmetry and are covered with thin pinnies, covered with a cilia again to increase the surface area and help to move the food towards the center mouth. The stem extends down from Kalyx, opposite Brachials. Most modern crinoid species, about 85%, lack the stem.

Modern Crinoids are the last remaining rest of not only Crinoidea class, but also a much larger population of echinoderms feeding filters. During the paleozoic and Permian era, Crinoidea had competition from such filter feeds such as blastoids, edrioasteroids and others. The main extinct event, which occurs on the border between the era of Permian and Triassic, about 251 million years ago, recorded the disappearance of about 95% of the world's life, including 98% of Crinoids and 100% other Fiechinoderms Feeding Lter Feeding. Articulata evolved somewhat later than otherCrinoid species that first appeared in a fossil record during the triassical period.