Carnivorous thingie in the deep sea

October 20, 2012 • 3:48 am

Nature continues to astound us: there are millions of undescribed species, and many of them defy even the most fertile imagination.

Have a look at the creature below (no, it’s not a plant), and guess what it is (I’ve left the title ambiguous).

It’s a sponge.  And if that’s not weird enough, it’s a carnivorous sponge: it apparently eats copepods, small aquatic crustaceans.

As you may know, the vast majority of sponges are filter feeders, removing organic particles (bacteria and phytoplankton) from water by sucking it in, taking out the good stuff, and expelling the water.  But in the deep sea, where organic material is scarce, some sponges have taken up the habit of eating animals. While this has been known for 17 years, beginning in 2000 and continuing through 2007, a series of deep-sea dives using remotely operated submarine vehicles have discovered these weird creatures living off the California coast at about 3300 m. down (that’s nearly two miles!).

The paper describing this new species, Chondrocladia lyra, was just published in Invertebrate Biology by Welton Lee et al. (reference and link to abstract below; full paper is below a paywall but I can send a pdf to those interested).  The paper is long and (for those who don’t love sponges) rather tedious, but the finding is exciting: this thing preys on other animals (sponges are, of course animals themselves).

Fig. 2 from paper: In situ images of Chondrocladia lyra sp. nov. recorded by ROV’s Tiburon and Doc Ricketts. Dives are identified by the first initial of the ROV followed by the dive number (see Table 1). A. Digital still image of T891-A2 (holotype)showing three vanes. B. Video frame grab of T197-A6 (paratype) showing two vanes. C. Video frame grab from T1046showing four vanes. D. Video frame grab from D26 showing five vanes.

As I said, Chondrocladia lyra is not the first carnivorous sponge to be discovered. Below is a picture of Asbestopluma hypogea (great genus name!) capturing a crustacean. A. hypogea is a Hexactinellidid sponge (aka a “glass sponge”), which spikes tiny crustacea and then curls round them before consuming its prey through phagocytosis. It lives in underwater caves off Spain, Croatia, and France.

Another carnivorous sponge!

Surprisingly, Chondrocladia lyra is not closely related to Absbestopluma – it is a demospongid, a group that makes up 95% of sponges. According to this recent phylogeny, Hexactinellida and Demospongiae are more closely related to each other than either are to the third group of sponges, the Calcarea.

It’s not yet clear how the weird sponge at the top captures copepods, since its feeding hasn’t been described in the wild; partly digested copepods were found embedded in the bodies of collected (ergo dead) specimens. Prey may be captured by small filaments on the surface of the sponge and then transferred to the surface of the “branches,” where they are engulfed and then digested. It will be hard to see this since the specimens obviously can’t be kept in aquaria, and they lie too deep to be observed directly.

h/t: Matthew Cobb via NeuroDojo


Lee WL, Reiswig HM, Austin WC, Lundsten L. 2012. An extraordinary new carnivorous sponge, Chondrocladia lyra, in the new subgenus Symmetrocladia (Demospongiae, Cladorhizidae), from off of northern California, USA. Invertebrate Biology: in press. DOI: 10.1111/ivb.12001

34 thoughts on “Carnivorous thingie in the deep sea

  1. Weird. I can understand why things might bumble into it but it’s not obvious why the don’t just swim off again. Is it possible to have underwater stickiness?

  2. I’ll again observe that any extraterrestrial life that presumably exists elsewhere in the universe will be at least as bizarre as these beasties, if not even weirder.

    Sadly, it will most emphatically not be green-skinned women who…like guys who…like…dramatic pauses.


        1. I think we can settle it right now.

          To say that any extraterrestrial life will be at least this weird is to say that there can be no extraterrestrial life less weird than this.

          That proposition is clearly false: in an infinite universe (which is what we appear to inhabit), all physically possible degrees of weirdness must exist.

          Even those green-skinned women are out there somewhere, and Max Tegmark can probably tell you approximately how far away they are.

          1. Well, sure — if you’re going to parse what I wrote as if it were a formal logical proposition.

            I think it was pretty clear, though, that I meant it as one would in normal conversation.

            Hypothetically, should humanity encounter an alien ecosystem, it would be reasonable to expect the members of that ecosystem to generally be at least as bizarre as those of the lest-related members of our own ecosystem. Happy?

            Besides, infinity is not congruent with normalcy. Imagine the Big Crunch theory had not been discredited, and further imagine that each Big Bang that follows a Big Crunch was identical to the Big Bang that came before, and that all subsequent events played out exactly the same way. Such a universe would be infinite, but there would be significant limits on the actualities that ever actually played out.


            1. The way I’d say it is that in any alien ecosystem we’re likely to encounter, the weirdest members will be at least as weird as anything we find on Earth.

              But if there’s an ocean full of swimming creatures, the top predators in that ecosystem will in all likelihood have fishlike or squidlike body plans, for reasons of biophysics that trump genetic divergence.

              So what we should expect from alien ecosystems is not ubiquitous weirdness, but a spectrum of forms ranging from strikingly familiar to utterly bizarre.

              1. There’d certainly be cases of convergence, but I’d hesitate to be as specific as you just were. Apex aquatic predators will be hydrodynamically streamlined, and will have an overall trout-like shape when swimming at speed. Assuming a fishlike body plan, with bones and a spine and a skull and gills and fins and even the mouth up front might well be going too far. As you point out, the cephalopods took a quite different route — and who’s to say that those’re the only two such routes to a trout-like profile?

                We can make other guesses: photosynthesisists will tend to have fractal body plans…maybe, depending on the actual solar flux and other environmental conditions. Again, compare Romanescu broccoli with a Saguaro.

                And what of apex land predators? Over the past several dozen million years, we’ve seen that role fulfilled by massive armored bipeds, then moderate-sized furry quadrupeds, and ultimately small naked bipeds. I don’t think there’s much you can extrapolate from that, except to suggest that, if the extraterrestrial’s original dominant land-dweller was a tetrapod, then chances are good that its descendants will be either quadrupeds or bipeds. That’s not a whole hell of a lot to go on.


  3. Jerry, could you please send me a copy of this article?
    I teach Invertebrate Biology in Guatemala and I would love to read it with my students.
    Thank you!

  4. I didn’t know the site yet, but got a link from a friend who’s always mocking me because I work with sponges. It’s great that the author of this blog had spent some attention to this awesome group. I was in the last sponge conference and could see the shinning eyes of excitement of the authors. It is really an amazing discovery.

    However, to improve your information on the post, I’d recommend you to correct the mispelling of Demospongiae – it’s not “demispongid”! And there’s a dreadful mistake when you say that Asbestopluma is an hexactinellid (BTW, this is a picture of an hexactinellid, but it’s not even close to Asbestopluma – the right pic should be some like this:

    Asbestopluma and Chondrocladia are both Demospongiae and of the same group: Poecilosclerida. This group is characterized by spicules that looks like hooks (chelae) which are responsible for holding the hairy legs of copepods. There’s no known hexactinellid, calcareous or homoscleromorph carnivorous sponges!

    Thanks for your VERY NICE post and congrat’s for the website.
    From Brazil,

    1. Corrected and new picture inserted (the one I used wss obviously labeled incorrectly). Thanks a lot!


      1. Great! I don’t want to be a moron, but you’re still telling that they belong to different classes of sponges. I repeat – all carnivorous sponges known to date are demosponges. And, as far as I know, they all belong to the same “order” Poecilosclerida.

        1. This is my fault – I wrote that bit of the post. I got scrambled somewhere along the line (and now need to change my lecture slides. Eek!) Thanks,

  5. …it is a demospongid, a group that makes up 95% of sponges.

    But I’m guessing the lion’s share of wealth and power is concentrated in the tentacles of the 5% aristospongids.

  6. Ah, the thingie. One of my favourite species (or maybe in creationist terms, I should call it a ‘kind’). It comes in many forms, but I’d have to say the one illustrated above is a classic of the thingie kind.

    Alternatively, it could be a radar array left by aliens on the ocean bed to detect – well, whatever it is that aliens like to detect.

  7. It will be hard to see this since the specimens obviously can’t be kept in aquaria

    actually, that’s not obvious to me. I’ve seen many deep sea specimens kept in aquaria at Scripps and Monterey.

    Is there something particularly different about this species?

    pressure is not a factor when dealing with species that don’t have compressible tissues.

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