Thanks to Morgan for suggesting this week&#39;s topic, the Antarctic Death Star!

Further reading:

Giant Monster Starfish ALERT

Echinoderm Tube Feet Don&#39;t Suck! They Stick!

Bodies of Starfish and Other Echinoderms Are Really Just Heads, New Research Suggests

The Antarctic death star [from first link listed above]:



The &quot;beartrap&quot; structures, magnified [from first link listed above]:



Show transcript:
Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.
It’s been way too long since we talked about an invertebrate, so this week we’ll look at one suggested by Morgan, the Antarctic death star.
It has a lot of other names too, including the Antarctic sun starfish and the wolftrap or beartrap starfish. Its scientific name is Labidiaster annulatus. I’m going to call it the death star because I think that’s hilarious.
As you may have guessed from its common names, the Antarctic death star is a starfish that lives in cold ocean waters near the Antarctic, AKA the south pole. But its common names also hint at how it gets its food, and this would be a good time to take a moment and be glad you’re not a copepod that also lives in the Antarctic Ocean.
The death star is reddish-brown on its dorsal side, white underneath. It’s a large starfish, up to two feet across, or 60 cm, and it also has a lot of legs, more properly called rays—up to 50 of them. The rays are long, narrow, and very flexible, and the undersides have rows of little structures called tube feet. All echinoderms, including starfish, have these tube feet and they’re used for several purposes. One important purpose is helping the animal stick to a hard surface, which allows it to climb around more easily and right itself if it gets flipped over.
For over 150 years scientists thought the tube feet acted like little suction cups, but that didn’t explain how a starfish or other echinoderm could stick to porous surfaces. It wasn’t until 2012 that a study was published explaining how the tube feet actually work. The tube feet exude tiny amounts of a sticky chemical that acts like glue.
The death star’s body also has little spines and bumps all over it, but it also has some structures that give the animal its other names, the wolftrap or beartrap starfish. The structures are called pedicellariae [PED-uh-suh-LAIR-ee-aye], which are also common in echinoderms. Most echinoderms seem to use them to keep algae and other organisms from settling on the body, although scientists aren’t completely sure. Pedicellariae have muscles and sensory receptors, and when something touches them, they snap shut like a trap. In the case of the Antarctic death star, its pedicellariae are extra big and really sharp. When a krill or other tiny animal brushes against one of these little traps, it grabs the animal and then the death star can eat it.
But that’s just part of what’s going on when the death star goes hunting, so let’s discuss it in more detail.
Most starfi

Episode 359: The Antarctic Death Star(fish)!

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