Fragile Star
Linckia columbiae
Physical Description
- Five-armed sea star, with thin arms and a small radial disc.
- Red and gray mottled coloration.
- The normal number of limbs is five, but can have anywhere from one to nine.
- Arms are often not symmetrical, due to ability to regrow new arms and discs.
- Maximum size is 4 inches in diameter.
Range
- Southern California to Peru.
- Ecuador (Galapagos Islands).
- May also be present in Hawaii.
Habitat
- Lives in the rocky intertidal.
- Found at depths of 0 to 500 feet.
Reproduction
- Embryos hatch into biradially symmetric (foldable on one line of symmetry) planktonic larvae that later transform into pentaradially symmetric (foldable on five lines of symmetry) juveniles with stubby arms.
Diet
- Sea stars eat mollusks and detritus.
Predators
- Fragile sea stars are considered rather inedible, although sea stars can be eaten by seabirds, fish, crabs, otters, and even other sea stars.
Interesting Facts
- The fragile star is known to undergo autotomy, or self-amputation, where one arm detaches itself from the disc. That arm then regrows a new disc and new arms, a process that can take six months or more to complete. This is often why fragile stars look asymmetrical – they are in the process of regrowing their bodies!
Sources: darwinfoundation.org; Reef Life Survey; Between Pacific Tides: Fifth Edition; National Aquarium; Benthic Invertebrates of Four Southern California Marine Habitats; sealifebase.ca
Photo: Matthew Meier