Plinthaster dentatus is a secretive and elusive species of starfish found in the Atlantic Ocean, that has been popularly dubbed “ravioli starfish” due to its uncanny resemblance to the popular Italian pasta.
The existence of this unusual starfish has been known since 1884 and, even though the species dates back to the time of the dinosaurs, its biology has been largely unknown to marine biologists and ocean observers. In fact, specimens have only recently been seen alive during a NOAA ocean exploration that spotted several ravioli starfish feeding on a sea sponge.
According to experts, the deep-sea creatures earned their nickname because of their pentagonal shape and puffy swollen gills, and they are also sometimes referred to as “cookie stars” thanks to the flattened cookie cutter shape they take when deflated and on display in museums.
“When they’re seen alive like this, there’s water that fills the body in order for it to breathe and so it’s that really strong swollen, inflated look, which gives it the look of a plump pasta,” Christopher Mah, starfish expert at the Smithsonian Institution, said.
The ravioli starfish got its first five minutes of fame a couple of years ago when NOAA published photos and videos showing the secretive seabed creatures in all of their glory and feeding on a sea sponge to boot. A behavior that had never been observed before and surprised a lot of marine biologists.
“We’d never seen them feeding, which in itself was novel — but the fact that they were in a group was amazing,” the expert added. “Seeing this attack, you think of them as living carnivorous raviolis attacking this sponge.”
The group feeding in the video shows that the marine creatures have the same level of complexity as Savannah mammals.
He compared it to “watching some antelope being brought down by by lions…followed by hyenas and many other kinds of predators.”