Lovely marine worms

March 11, 2014 • 2:02 pm

You don’t like worms? That’s a narrow-minded attitude—especially in light of these beautiful marine worms, photographed by Alexander Semenov, posted on Colossal, and called to my attention by several readers (how do you people find these things?).

I’ve chosen a few for your delectation, but go look at them all. I have no idea what the species are (they’re all polychaetes, a class of segmented worms [“annelids”]) but perhaps some readers know. Some of these have fantastic morphological complexity.

The site’s description follows, and be sure to look at Semenov’s photos of jellyfish and starfish.

Our favorite photographer of everything creepy and crawly under the sea, Alexander Semenov, recently released a number of incredible new photographs of worms, several of which may be completely unknown to science. Half of the photos were taken at the Lizard Island Research Station near the Great Barrier Reef in Australia during a 2-week conference on marine worms called polychaetes. Semenov photographed 222 different worm species which are now in the process of being studied and documented by scientists.

The other half of the photos were taken during Semenov’s normal course of work at theWhite Sea Biological Station in northern Russia where he’s head of the scientific divers team. We’ve previously featured the intrepid photographer’s work with jellyfish (part 2part 3), and starfish.






24 thoughts on “Lovely marine worms

  1. (Sorry for my english). Beautiful pictures! They are plenty of families of polychete worms, with very different shapes and specialisations. Four of them are illustrated here.

    The first and the third are Terebellidae, characterized by a number of anterior tentacles (ciliated and U shaped in cross section) which explore the neighbouring almost autonomously and bring back food particle to the mouth. The little “bushes” just behind the tntacles are gills. They live in tunnels in the mud or in tubes they built out from mucus and sand grains. It’s awesome to look at them alive. See for example

    The second is probably a Spionidae, they have typically two long tentacles spiraling like sheep horns, and lanceolate gills on each segments.

    The third is probably a Serpulidae. They live in calcareous tubes and show a crown of tentacles, one of them transformed into a cork to close the tube when the worm withdraws into security.

    And the most fantastic is the last one, a Chaetopteridae. The two appendices a bit horseshoe-like are used to hold a net of mucus, and the foliate segments behind work like a propeller, or more exactly like a Archimedes’ srew. The worm lives in a U shaped tunnel, and the “propeller” generates a water flow troughout (from tront to tail). The comestible particles are trapped in the mucus net. When it is full, the worm eats borh the net and its content, and secrete and new net.
    It’s an awesome example of how evolution frequently works, by metamerisation of identic segments – that is the basic structure of worms – followed by specialisation of some of them, here for trapping food and circulating water.

    1. Thank you. These are very interesting details. I was supposing that the ones with long tentacles concentrated at one end would live in tubes, maybe extending their tentacles out to gather food particles.

  2. For ‘simple’ animals they have almost baroque forms. I fondly remember Chaetopterus from undergrad invertebrate zoology classes, with its mucous bag ‘fishing net’.

  3. I believe it’s the case that although there are still “polychaetes”, the Phylum Annelida has been reconstructed, so that the classes Oligochaeta, Polychaeta and Hirudinea have been dropped in favor of groupings more reflective of evolutionary relatedness: the clades Errantia and Sedentaria.

    1. I teach classes in Marine Zoology, including sessions on worms, so I think I’m pretty up to date with this stuff. “Errantia” and “Sedentaria” are handy functional categories, but haven’t been regarded as valid taxonomic groups for decades. As with so many other groups, the formal classification of the various groups of “worms” is now dictated by the findings of molecular biology. What this shows pretty clearly is that Oligochaeta (earthworms) and Hirudinea (leeches) are actually nested within Polychaeta, i.e. they’re not separate classes at all. The same is true, incidentally, of the former phyla Sipuncula, Echiura and Pogonophora. As far as the molecules are concerned, they’re all just weird polychaetes.

      For full details, see Struck, T.H. et al. (2007) BMC Evolutionary Biology 7: 57.

      1. Yes, but Struck et al 2011 (Nature 471, 95-98) and Struck 2013 (PLOS ONE 8 e62892)
        nevertheless keep Errantia and Sedentaria as valid groups, the latter including earthworms and leeches (Clitellata)as well as Echiurids… Sipuncula and Chaetopterus are apart.
        If one admits that evolution strongly modified the clades leaving the sea(Clitellata), bluring their relationships, the 19th century zoologists had rather good insights!

  4. “The angels all pallid and wan
    uprising, unveiling, affirm
    That the play is the tragedy, Man,
    and its hero the Conqueror Worm.”
    -From Ligea, by Edgar Allen Poe

    I find these creatures beautiful and terrifying at once. They are far stranger than the most imaginative creations of science fiction.

    1. Well, we aren’t *these* kinds of worms. These are all protostomes and we, OTOH, are deuterostomes. The difference is how we embryologically develop our gut. But these lovely creatures are nonetheless our cousins, be it ever so many times removed. The protostome/deuterostome ancestor (PDA; something funny about that abbreviation) was undoubtedly ‘wormlike’, in the sense that it didn’t have a very complicated body plan (some think), but it was only really a ‘worm’ if one stretches the term somewhat.

  5. When G*d made these, he must have been on the wildest celestial LSD trip of his entire existence. 😉

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