Don’t You Dare Call the Deepstaria Jellyfish a Whale Placenta

Deepstaria jellyfish aren't usually this active–this one is caught up in the wash of the submersible. It looks a lot like a hot air balloon, doesn't it? Or does a hot air balloon look like Deepstaria? Something to think about.

The internet could have sworn it was looking at a whale placenta. Not that many folks could say they’ve ever seen a whale placenta, but it seemed to be a reasonable explanation for the underwater video that popped up in May 2012 of a dancing curtain of flesh. Hell, it could be a NEW SEA MONSTER, as the YouTube title yelled.

That guess was closer, but this was no monster. It was one of the weirdest jellyfish in the sea, Deepstaria. This underwater oddity relies not on long stinging tentacles to catch its prey, but on its entire body. It’s a floating blanket, enveloping victims and then cinching its bottom bit shut to create a balloon of death. And it doesn’t appreciate people calling it a whale placenta.

Roaming the oceans are two species of Deepstaria, named after the submersible Deepstar that first spotted one intact in the 1960s. Deepstaria reticulum, shown at top, features that beautiful red hue, while the other, Deepstaria enigmatica, appears whiter. Otherwise, they look largely the same.

“Most jellies would have a relatively small bell and then relatively long tentacles,” says Steven Haddock, a biologist at the Monterey Bay Aquarium Research Institute. “These guys have the really big bell that’s almost like a trash bag or something, and pretty much no tentacles.”

Deepstaria are real loosey-goosey, tumbling around the deep. They seem to be able to manage some measure of undulation, but have nowhere near the power of your typical jelly. (Interestingly for such strange jellyfish, their closest known relative is the most typical of jellies, the moon variety, which you’ll find in any self-respecting aquarium.)

The thing is, in the deep ocean, being spry isn’t necessarily an advantage. Deepstaria does just fine by suspending in the water column and waiting for prey to crash into it. “They can be a meter large, so they could certainly have small fish and shrimp end up inside of that bell,” says Haddock. When the jelly detects something in there, it tightens the edge of the bell shut like a drawstring on a fleshy trash bag.

Now the jelly just has to get the food into its gob. How it does so is still a bit of a mystery, but naturalist Ron Larson has a hunch. Like other jellyfish, Deepstaria has stinging cells called nematocysts, he says, only instead of covering the tentacles, they likely cover the bell or other concentrated patches of flesh. Deepstaria also has little hair-like structures lining the bell called cilia, which collectively act as a conveyor belt to ferry the prey toward the mouth.

Deepstaria jellyfish create a balloon of death to overwhelm their prey. They’re available now for kids’ parties at a very low fee.

So say something like a little copepod crustacean makes the mistake of wandering into the bell. “Eventually the copepod is going to hit some of the nematocysts, which will stop it from swimming,” Larson says. “And then the cilia and muscular contractions are going to help get the prey close enough to the lips—the oral arms we call them—so that it can eventually get into the stomach.”

You may have noticed from these here GIFs that Deepstaria has a sort of mesh structure running through its body. And you may assume that mesh is for supporting the bell, which is just a seventh of an inch thick. In fact, these lines are connected to the stomach, and help carry nutrients throughout the jelly’s body. After all, a jellyfish three feet wide has a whole lot of surface area to provide for. The muscle that cinches the bell closed is particularly hungry for energy.

And Deepstaria needs every inch of that surface area. Food is scarce in the deep compared to, say, a bustling coral reef. By evolving to be so big, the jelly casts a bigger net to better its chances of snagging prey.

At least one critter, though, can wander into Deepstaria scot-free: the isopod. These crustaceans aren’t winning any titles for their good manners. One species, for instance, will crawl into a fish’s mouth, devour its tongue, and replace the organ with its body because hey, someone was bound to. It’s a parasite if there ever was one.

Here’s a good shot of an isopod catching a ride in a Deepstaria enigmatica and looking coy as all hell.

The variety that hangs out inside Deepstaria, though, may or may not be parasitic—the relationship between host and parasite here still isn’t clear. “They’re probably just taking a little bit of a tax on what the jelly eats,” Haddock says. “Whatever the jelly captures, the isopod takes its share. It could be parasitic, but if it ate too aggressively it would destroy the jelly and it would no longer have that nice habitat for itself.”

What is clear is that the isopods are great at finding these hosts. “I don’t know if we’ve ever seen one of those jellies that doesn’t have one of those things in it,” Haddock says. And the isopods might be setting up shop in Deepstaria and Deepstaria alone—scientists haven’t found them on any other variety of jelly.

Stranger still, Deepstaria don’t roll in big groups like other jellies might, which would theoretically make it difficult for the isopod to get its offspring to other jellyfish. “If you think about how far between those jellies are from each other,” Haddock adds, “it’s pretty incredible that [the isopods] could find and set up that association.”

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