Invertebrates
Basket Star
Gorgonocephalus · also called basket stars
By day a basket star looks like little more than a tightly wound knot perched on a rock or a sponge, easy to overlook entirely. After dark it unfurls into something else altogether, five arms branching and rebranching dozens of times into a wide, tangled net held up into the current, waiting for drifting plankton to arrive.
Overview
The basket star, genus Gorgonocephalus, is a filter-feeding relative of the brittle star found in cold and deep waters worldwide. Its five arms branch repeatedly into a dense net, curled into a tight ball by day and spread wide to feed by night.
A brittle star’s arms taken to an extreme
Where an ordinary brittle star gets by with five simple, unbranched arms, the basket star’s same basic five-armed plan has multiplied into dozens or hundreds of smaller branches, turning a straightforward body plan into an efficient, wide-reaching feeding net.
Status
Least Concern — widespread and secure across suitable cold-water and deep-water habitat worldwide.
Basket Star: common questions
How is a basket star different from a regular brittle star?
A basket star belongs to the same broader class as brittle stars and shares the same basic five-armed body plan, but where a typical brittle star has five simple, unbranched arms, a basket star's arms divide and redivide repeatedly into dozens or even hundreds of smaller branches, forming a dense, net-like structure quite different in appearance from its simpler relative.
Why does a basket star curl into a ball during the day?
A basket star typically curls its highly branched arms into a tight, compact ball during daylight hours as a defensive posture, reducing its visibility and overall vulnerability to predators while it remains largely inactive, before unfurling again after dark to begin actively feeding.
Why does a basket star position itself on elevated structure?
A basket star often perches on coral, sponges, or rocky outcrops specifically because this elevated position lifts its branched feeding arms up into stronger water currents, which typically carry a greater volume of the small planktonic food particles the basket star depends on compared with currents closer to the seafloor.
When is a basket star actually feeding?
A basket star generally feeds at night, unfurling its extensively branched arms into a wide, spread net shape to intercept drifting plankton and other small particles carried past by the current, a pattern that contrasts with its tightly curled, largely inactive daytime posture.