Sea Lily Neocrinus decorus
Sea lilies are stalked relatives of feather stars and usually remain fixed in the same place after developing from a settled planktonic larva. However, while Neocrinus decorus and other, similar sea lilies cannot swim, like shallow-water feather stars, they have been filmed dragging themselves over the sea bed by their arms. To do this, they appear to break off the end of the stalk, then reattach to the substrate using flexible, fingerlike appendages on the stalk. In this way sea lilies can escape from predatory sea urchins. The stalk consists of a stack of disk-shaped skeleton pieces called ossicles, and looks like a simple vertebrate spinal column. Sea lilies feed by spreading out their numerous, feathery arms against the current and trapping plankton. Food particles are passed down the arms and into the mouth.
Fossil Evidence for Sea Lilies
Today there are relatively few sea lily species, all of which live in deep water, but this group once thrived in ancient seas. Entire fossil sea lilies are rare, but loose ossicles from their stalks are very common in some limestones.
- Class Crinoidea
- Height Up to 24 in (60 cm)
- Depth 500–4,000 ft (150–1,200 m)
- Habitat Deep-sea sediments
- Distribution Tropical waters of western Atlantic Ocean