The Pink Meanie Menace

by Jennifer Frazer on February 16, 2011

Sai, hooman, ware can I finds anutter jelli to nom? The pink meanie, Drymonema larsoni. Credit: U.S. Geological Survey Department of the Interior/USGS U.S. Geological Survey/photo by Harriet Perry

It’s no secret that jellyfish are capitalizing on the giant hole in the ocean left by our past (and in some cases, continuing) strip-mining of its waters for seafood, baleen, and whale oil. Their populations have blossomed like a Dutch tulip market. But now it seems another population may be benefiting from the open water rush: cannibal jellies*.

Scientists recently discovered an entirely new species of jellyfish-eating jellyfish, the colorfully named “pink meanie”, according to a recent article in The Biological Bulletin. According to a USGS report, no one had reported or could recall seeing a single pink meanie in the waters off of Puerto Rico prior to 1999, and no one could tell what species it was.

Yet that year, scientists estimated an explosion of some 25 million meanies. That’s a lot of meanies. But it’s not nearly as many as the boom of common moon jellies they were feeding on around Puerto Rico that year: an estimated two billion.

Is it possible we are only noticing this heretofore reclusive or minor species now because jellyfish prey pops are blossoming, and the environment is primed for jellyfish-eating jellies to do well? Food for . . . er, thought.

There’s certainly no question that pink meanies are good at eating moon jellies. One pink meanie was found with its tentacles stuffed with 34 moon jellies. That is not, as my father would say, a lady-like sized bite. Nor is this: look carefully at the diameter of the bell of the nearly transparent moon jelly in the third photograph in this slideshow. It is huge! Either the pink meanie has moxie . . . or it’s an eyeless and nearly brainless invertebrate with a voracious appetite. One of those two.

Originally, scientists thought they might have found an invasive species from the Mediterranean and Atlantic called Drymonema dalmatia. But closer investigation revealed molecular and morphological differences signficant enough to warrant a new species designation. What’s more, they decided that the uniqueness of the entire Drymonema group was such it should be in its own family:

This revision emphasizes the remarkable morphological disparity of Drymonematidae from all other scyphomedusae, including allometric growth of the bell margin distal of the rhopalia, an annular zone of tentacles on the subumbrella, and ontogenetic loss of gastric filaments.

As far as I, <echo chamber> A Trained Biologist </echo chamber> can figure, that means something like that the bell is scalloped rather than smooth-edged (see pictures), the tentacles emerge from a ring-shaped zone rather than in clusters, and they lack from the beginning of their development the stinging stomach filaments that kill any food that manages to reach standard jellyfish stomach pouches alive. Somehow I’m imagining the loss of something you might find in the center of a sarlacc pit, but it’s probably not that awesome. Please, jelly experts, help correct me if I have misinterpreted.

For those of you interested in Extreme Closeups of this jellyfish’s color, anatomy, and texture (including the scalloped edges), see here.

Sadly, though these jellies feed on other jellies and may help to control their populations, they are still jellyfish, they still have stingers, and the stingers can still hurt humans. But (and this is just a guess) they probably cannot hurt other jellies enough to stop their relentless takeover of the increasingly undefended turf in Earth’s oceans**.

These jellies fall into to the major group Scyphozoa (sky-fu-zo-uh), the “true” jellyfish. The name comes from a Greek drinking cup whose shape jellies are supposed to resemble. They, in turn, are one of four major groups in the phylum Cnidaria (Nye-DAR-ee-uh). Their close relatives in the phylum are the Anthozoa — primarily the sea anemones and corals, including the sea fans, sea pens, soft corals, organ-pipe corals, tube anemones, stony corals, and black corals — the Cubozoa, or deadly box jellies, which I was mighty afeared of bumping into on my pelagic night dive last spring, and the Hydrozoa, or hydroids, fire corals, man’o’war jellyfish, and by-the-wind sailors.

Your homework: See how they fit together here at the Tree of Life, or hit up the Google with one of the names that intrigues you to see what it’s all about. I assure you, the creatures in these groups are some of the most amazing on Earth.

And lest you think I have a pathological hatred of jellyfish, know that I have an entire bathroom decorated in a jellyfish theme — including one plush jellyfish and one glow-in-the-dark jelly. Yes, my nerdiness knows no bounds. Plans are also in progress to create an entire lichen- or Haeckel-themed room . . .


*Of course, that’s not really accurate. Unless they’re eating members of their own species (which they may well), they’re still just predators who happen to feed on their close relatives. That’d be like saying hunans who eat monkeys or apes are cannibals.

** Wanna do something about it? Download a seafood watch wallet card and use it when you are buying seafood or sushi. You could also consider supporting the ocean conservation organization of your choice. And of course, do what you can to fight climate change/ocean acidification. I don’t need to tell you what those things are.

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February 16, 2011 at 6:31 pm

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kati February 16, 2011 at 8:35 pm

yes, everyone! use that seafood watch list! and i’m going to want to see pics of the lichen room :)

Jennifer Frazer February 17, 2011 at 3:32 pm

Me too. : ) Although I think I draw the line at plush lichens.

Adam February 23, 2011 at 10:07 pm

Looking forward to “dissecting” this entry this week for my advanced Science/Medical Writing Workshop at Johns Hopkins University. I proposed this site last week as a blog or science writing-related news site to follow for the semester, and our instructor liked it and picked this entry for me to dig into for next week’s class. Thanks for creating a most unique and informative site Jennifer!

Jennifer Frazer February 24, 2011 at 7:19 am

That is awesome. Thanks for letting me know! It wasn’t so long ago I was in a program just like yours (’03-’04) — and we didn’t even discuss science blogging at all!

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