A Quick Overview of One of My Favorite Marine Invertebrates.





Basket stars are strange. Let's get that out of the way. Not many animals, especially of the spineless variety, can cause people to be curious, puzzled, grossed out, and just straight up weirded out- all at once.





So let's go ahead and demystify this alien looking monster of the deep.





What are basket stars?

Basket stars are as mentioned invertebrates. Despite looking like nothing but spine they have neither backbones nor a spinal cord. Specifically they are in a group of marine invertebrates known as echinoderms. A relative of basket stars, sea stars possibly the most famous marine invertebrates, are also echinoderms.

If sea stars are the Taylor Swift of marine inverts, are basket stars Nine Inch Nails?





Now echinoderms are more than just sea stars and basket stars. Sea cumbers, sand dollars, and sea urchins are all echinoderms. Another lesser known echinoderm is the brittle star. Known for their spiny arms which they move quickly in a snake-like manner, it is within this branch of the creepy crawly family tree that we find basket stars.





So now we know basket stars are not just marine invertebrates, but are echinoderms that form a suborder within the brittle stars.





Basket Basics

But what about basket stars themselves? Why do they look so weird compared to other stars? Where do they live? How big do they get?





Well Armed - Vancouver Island, B.C.

Well let's start with that crazy look. It all boils down to this: basket stars are suspension feeders. Many of us know how the ocean is full of life drifting through the water. Whether it's microscopic plant-like phytoplankton or massive jellyfish, much of the life in our oceans is suspended in the water, carried by currents.

Basket stars collect small plankton from the water column utilizing small hooks and spines on their arms. This is why basket stars have so many arms; the more arms they have the better their trap, and the more plankton can be caught as they drift past the basket star in the water.





These snared plankton are placed in mucous and the basket star moves the mucous-trapped plankton into its mouth. Yes, basket stars have mouths. Not only do they have mouths, but their mouths are star shaped and filled with spines. If nothing else, a testament to how dedicated basket stars are to being rad and creepy.





So if you're say a small planktonic worm and you want to avoid the spiney mouthed basket stars of doom, where should you definitely not go? Unfortunately for you, basket stars live in almost all the oceans of the world. But you may take solace in the fact that basket stars are benthic invertebrates, meaning that they live on the seafloor. Basket stars are known for being one of the cool creatures that deep sea researchers may find while piloting remotely operated vehicles (ROVs). Chilean basket stars can live as deep as 900m or nearly 3,000ft deep! I've encountered basket stars as shallow as 15ft deep in British Columbia but more frequently I tend not to see them until I'm at least 80ft in depth. But basket stars have another trick up their many many sleeves when it comes to feeding. Often in Alaska I'll see basket stars climbing up gorgonians, a type of coral. By gettig up higher in the water column basket stars are able to more efficiently catch plankton.





Coral-esque Step Stool - Alaska

So how big do these monsters of the deep get? The basket stars pictured above are all Gorgonocephalus eucnemis, a species who can get over 25 inches in diameter. A species found in the Caribbean, Astrophyton muricatum, can get up to a foot and a half in size. Compare this to their brittle star relatives, who get no larger then 8 inches in diameter and you might be a little impressed. But consider that even the largest of the sea stars gets no larger then 40 inches and you may be very impressed, or terrified.





So there you have it, some basic information on a very cool, intriguing, and somewhat hair-raising animal that is currently hanging out thousands of feet down in the ocean, sitting elevated off the seafloor catching helpless planktonic life carried by ocean currents to their multi-armed doom.













More Information

My personal recommendations for additional resources on basket stars:





Online

Seattle Aquarium

Walla Walla University

Oceana





Text

Lambert, P., & Austin, W. C. (2007). Brittle stars, sea urchins and feather stars of British Columbia, Southeast Alaska and Puget Sound. Victoria: Royal BC Museum.



