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 . . .

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*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.

Yet that is precisely what scientists have found. In 71 percent of the black coral species examined at up to 1,300 feet beneath the surface, scientists found symbiotic algae either identical to or nearly identical to that found in surface corals. That’s amazing! What the heck are they doing there? Is the tiny amount of light that makes it enough to sustain them? Or do they retain their photosynthetic apparatus in spite of not using it? Do the corals simply keep algae because there’s no great cost to *not* doing so, and it’s already programmed into their genes?

Black corals, like all coral, are actually cnidarians like jellyfish, anemones, and sea pens. In essence, they are animals that have taken up underwater lichenization: primary colonizers that slowly build up the infrastructure (lichens: soil, coral: calcium carbonate high-rises and sand) that will support other life. But instead of fungi trapping eukaryotic (nucleated) green algae or cyanobacteria (as in lichens), we have colonial cnidarians trapping dinoflagellates called zooxanthellae. Each little coral individual, or polyp, is like an upside down, anchored jellyfish (complete with little particle-trapping, retractable tentacles) with photosynthetic dinoflagellate tenants inside. Black coral polyps aren’t black, but their skeletons are. Black corals also have tiny spines on their skeletons, lending them the name “spiny thorn coral”.

Let’s have a closer look at the renters:

Symbiodinium -- the dinoflagellate zooxanthellae of black corals too. Creative Commons David Patterson and Mark Farmer. Non-Commercial Use Only.

Look carefully: you will see little brown spots, which are the symbionts inside the symbionts; that is, their own endosymbiotic chloroplasts, which were once photosynthetic bacteria. At some point long ago, they themselves were sucked in by an ancestral dinoflagellate and co-opted for its own personal use.

Corals aren’t the only ones that keep dinoflagellate food replicators right inside them (“Cellulose. Earl Grey. Hot.”): Other organisms that can host zooxanthellae — several of which, unless you’re a biologist, you’ve probably never heard of —  include jellyfish, clams, foraminifera, sea slugs, ciliates, and radiolaria. Depending on how you look at it, these algae are either getting free stays and all-you-can-make buffets left and right in the ocean, or they are getting bullied by half the kids in school. The relationship between the dinoflagellate and its coral hosts, in particular, seems ambiguous as best right now; while some scientists argue they benefit from the association, others say the coral is holding them captive and forcing them to do its bidding (in support, they point out that the algae can reproduce perfectly fine — and many times faster — on their own. The same is not true for the coral). The same arguments have been made for the lichen association, and I think the jury is still out on that one too.

Not all dinoflagellates are zooxanthellae, or photosynthetic symbionts. Nor are they even all photosynthetic. About half are not. They’re called dinoflagellates (supposedly) due to their whirling (dinos) whips (flagella), or tails. In the photo above, you should be able to see the trailing, or longitudinal flagellum which the dinoflagellate uses to propel itself, and the transverse flagellum, which wraps around the equator of the cell. Both of these flagella may come with their own ridged, groovy wrap-around exterior storage compartments, delightfully called the cingulum and sulcus. The transverse flagellum mostly stays in its groove and is believed to function as a rudder. Here are some pictures that might give you a better feel for how all this fits*.

But the chloroplasts of these creatures tell an amazing story. In most plants, chloroplasts (and mitochondria) have two membranes, which scientists believe is evidence that chloroplasts and mitochondria use to be free-living bacteria before they were tamed and fused with ancestral eukaryotic cells like our own (presumably, by one ancient cell trying to eat another and failing, with the indigestion-causing bacterium going on to start working for the cell. You know what they say . . . if you can’t beat ’em . . . ). But they’ve also long known that some marine algae have an even cooler situation: three or more membranes. What could be the explanation? Well, they seem to be evidence of multiple endosymbioses, or failed eating attempts that resulted in a cooperative relationship. And some of them were of algae, not just bacteria. In some zooxanthellae, there’s still a vestigial nucleus of one of those ancient algal victims wedged between some of the plastid membranes! So in essence, black corals are symbionts inside symbionts inside symbionts inside symbionts . . . you get the idea. Amazing!

A few final details about dinoflagellates — some of them also possess light-sensing eyespots, and one species has the smallest known eye. When corals bleach in water that is too hot (an increasingly common occurrence these days), they expel their zooxanthellae and die — and the loss of the algae’s colored pigments is responsible for the sudden whitening. And finally, a separate, free living group of dinoflagellates are the organisms responsible for the annoying and neurotoxic phenomenon you may know as a red tide.

But, while interesting, none of this helps explain why corals at extreme depths would retain the same or nearly same algae as corals found within feet of the surface. Here’s the conventional wisdom:

Hermatypic (reef-building) corals largely depend on zooxanthellae, which limits that coral’s growth to the photic zone.

I’m not an oceanographer, but it seems to me that below 1,000 feet deep is not the photic (light) zone. Perhaps the algae are the equivalent of cave fish: blind and pale but still fish in every other way. Sounds like a job for a dissecting scope . . . or are they eking by on the .0000001% (aprox.) of light that makes it that deep? Given that some black corals have been judged over 4,000 years old, with growth rates as low as 4 micrometers per year, perhaps that’s not out of the realm of possibility . . .

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*Tron dinoflagellate courtesy of Kennesaw State University.

"Come here often?"

Here in Boulder there is a restaurant that serves the proposterously-named “Juxtaposition of Duck”. I could not resist when it came to titling this post. From the Beeb, I present to you a gorgeous eye-candy gallery of Arctic jellyfish. One of my great delights in studying the diversity of life on this planet is the variety of form, texture, and color. Slime molds, lichens, and jellyfish, in particular, provide some of the best highs. Enjoy, and Happy Friday.

BTW, is it just me, or does it seem like the caption for #2 should be, “Luke, I am your father!”?