Meet the Chocolate Chip Starfish And It's Unusual Relatives

Video highlights from World's Weirdest

Super gooey slime stars and a predatory “monster” starfish from Antarctica are among nature’s most fascinating invertebrates.

The Eastern Pacific’s Nidorellia armata is often called a chocolate chip starfish, but the one I saw turned out to be Protoreaster nodosus, an Indo-Pacific species that sports many color variations, from tan to deep orange. It also has an Indian Ocean relative, Protoreaster lincki, that’s strikingly red and white.

“All the starfish in that group are heavily armored,” Mah says, with those “chips” being spines likely meant to deter hungry predators (the exact opposite purpose of real chocolate chips).

Protoreaster nodosus, also nicknamed the chocolate chip starfish, lives in the Indo-Pacific [Image: Poelzer Wolfgang, Alamy]

Why starfish have such vibrant colors is still unknown, Mah adds.

Interestingly, baby Oreaster reticulatus, the only Eastern Atlantic member of the family Oreasteridae, are more blandly colored than adults—perhaps allowing them to blend into seagrass beds, according to Bob Scheibling of Dalhousie University in Nova Scotia.

Adults, on the other hand, live in open areas and are a more curiously distinctive bright orange.

Mah has written about some other cookie-like starfish from the family Goniasteridae on his Echinoblog, but he has a soft spot for Calliaster regenerator and its “screwdriver-like spines.”

Then there are so-called “slime stars,” in the family Pterasteridae, including Pteraster and Hymenaster, which are known for being grossly gooey.

“You can pick one of these animals up and it will emit a huge volume of mucus as a defense,” Mah says.

But the animal has a surprise up its gloppy sleeve: “Pteraster and its relatives have a second body covering, sort of like a circus tent that hides its actual body,” Mah says.

“In some species of Pteraster, baby [starfish] live in this space between the ‘circus tent’ and the surface of the actual body.”

Another of Mah’s favorites is Labidiaster annulatus, an Antarctic starfish that he dubbed “the great white shark of starfish.”

As omnivorous opportunists, starfish have many different ways of eating. Some evert, or push out their stomach through their mouths and suck up microalgae or small animals.

But the Antarctic predator has up to 50 arms covered with structures called pedicellariae, which act like “bear-trap claws” to grab krill or crustaceans.

The Antarctic predator Labidiaster annulatus has up to 50 arms covered with structures called pedicellariae, which act like “bear-trap claws” to grab krill or crustaceans [Image: Waterframe, Alamy]

Once the prey is grabbed, the starfish’s tube feet carry the food down to the mouth where it’s eaten alive,” Mah says. At 2-feet (0.6-meter) long, relatively big for a starfish, “They’re like a giant monster!”

But being starfish, of course, “they’re more in danger from us than to us.”

The same could be said for cookies.

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