Metacrinus rotundus
From Wikipedia, the free encyclopedia
| Metacrinus rotundus | |
|---|---|
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| Specimen in situ | |
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| Museum specimen | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Crinoidea |
| Order: | Isocrinida |
| Family: | Isocrinidae |
| Genus: | Metacrinus |
| Species: | M. rotundus |
| Binomial name | |
| Metacrinus rotundus Carpenter, 1885 [1] | |
Metacrinus rotundus, the Japanese sea lily, is a species of stalked crinoid in the family Isselicrinidae. It is a species found off the west coast of Japan, near the edge of the continental shelf at a depth of around 100 to 150 metres (330 to 490 ft) deep. This is the shallowest-living species among the extant stalked crinoids.
In appearance, the Japanese sea lily resembles a feather duster. It has a central mouth surrounded by a crown of many-branched feeding arms. These are jointed and can coil up or unroll to expose the feathery pinnules on either side to the current. Each pinnule has several rows of tube feet and a central ambulacral groove that leads to a groove on the arm that continues down to the mouth. The crown is supported by a tough stalk composed of calcareous ossicles bound together by ligaments. At the base of the stalk is a disc-like sucker and the sides of the stalk bear five whorls of cirri (clawed appendages). The stalk continues lengthening during the animal's life and may reach 40 centimetres (16 in) and the arms can grow to half that length.[2][3]