Japanese Sea Lily

• Stalked crinoids dominated the seabed through the Palaeozoic and formed veritable underwater forests whose remains make up entire beds of limestone; today they survive in deep water.
• Despite the stalk, it is not fixed for life: it can detach and crawl slowly across the bottom to a better spot, something only filmed in recent decades.
• Its stalk is made of stacked discs that come apart when it dies and turn up as fossils shaped like coins or screws.
• It keeps its stalk for life, unlike most crinoids alive today. Stalked sea lilies are now nearly all deep-water animals, and this one is an accessible exception.
• That is precisely why it is a valuable laboratory model: it can be dredged at moderate depths off Japan and kept alive, which is all but impossible with the abyssal crinoids.
• It can shed its stalk along breakage planes and regrow it, and the shed fragments can survive on their own for a time.
• Stalked crinoids dominated the seabeds of the Palaeozoic and are now a relict: this group is what remains of those sea lily forests.

Habitat & environment

Rocky and gravel bottoms of the western Pacific, between 100 and 500 m

Sources consulted: Carpenter (1885); Oji, estudios de biología de crinoideos con tallo en Japón; Nakano et al.