Odd isn’t that odd

It’s been a pretty technical series for a while. Let’s do a little bit of fun talk.

blobfishTake a look at this thing, which is properly called Psychrolutes marcidus and not “this thing,” or by its common name, the blobfish. None of this is a surprise to the readers because the intersphereweb is chock-full of blobfish memes. Let’s shelve all that and talk biology. Fun biology.

Quick info: it’s from the deep-sea environment off the coasts of Australia, New Zealand, and Tasmania. Really deep sea, people-killing pressure deep. You might be surprised how rich in nutrients these areas are, because, well, everything sinks there. They’re also fascinating because sunlight doesn’t penetrate that far, and so the ecosystem is proportionately more heterotrophic than most. That means that photosynthetic organisms aren’t operating as producers, or sources for energy for everything else. Instead the primary or baseline food (meaning, who eats it gets eaten), is the sifting-down detritus from the world above.

Now pick one of the following questions – the one you really would enjoy knowing about. Post it below, and if you’re feeling feisty, look up something-or-other to get started on the answer.

  • How does it work? (this is functional anatomy and physiology)
  • What does it do? (this is ecology and behavior)
  • Who is it? (this is systematics and taxonomy)
  • How did it get this way? (this is evolutionary talk)

I’ll be the classic thought-provoking prof participant, only without the stereotypical snark and patronizing. Here are some points to think about along the way.

You probably already know this too, especially since Michael Hearst did the heavy lifting (see link below). Pictures like the one on the left aren’t really fair. As a deep-sea animal, its shape is maintained in the context of intense pressure, and all that shapeless glop – the blobness – is certainly not what it looks like.

Also, plenty of creatures display a human-like face … if it’s tilted just so and various features are arranged just so. Don’t forget that the human viewer can make an anthropomorphic face out of any closed shape with as little as one feature marked inside it. Again, the “Uncle Sid” effect displayed here isn’t the fish’s ordinary in-life face.

Righty then, reply to see some discussion happen. Here’s my aim in this: to show that every creature is odd … meaning that the answers to the four questions provide a completely different framework for talking about what is usual vs. unusual. I’ll show you how to see that the “oh my god so weird” blobfish isn’t exotic, but is endlessly interesting.

Links: Ocean Treasures (excellent gallery), Michael Hearst’s Songs for Unusual Creatures

Next: Count Bacula, part 1

 

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8 thoughts on “Odd isn’t that odd

  1. Now I’m going to be very sad every time I see a blobfish picture. I mean, I already knew a fish out of water wasn’t in a good place, but now I know it’s completely losing bodily integrity because it’s in an environment where gravity acts on it in a way that it never would in its buoyed-in-high-pressure-water home It’s like if you as a human were stuck on a planet whose gravity was so high it crushed you into a sad lump.

    So what’s all this with “no muscles.” How can a vertebrate live with no muscles? What are its fins for if it doesn’t have muscles to move them?

    I guess that’s a “how does it work” question.

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    • It is! Here are the starting principles.

      All animal bodies are hydrostatic, relying on membranes, spongy tissue, tubes, and glop to maintain various pressures in various places, and for the most part, that’s water pressure. In an aquatic environment, for creatures with no non-aquatic evolutionary history, these mechanisms are likely to be the primary ones involved in the integrity of body shape. Their whole context of life includes significant external pressure upon the body from all directions, with the “hang” of gravity being a minor biomechanical thing (for us, by contrast, it’s the thing).

      So uh it’s kinda gross, but any time a deep-sea creature is fetched above the surface, its body-cavity membranes and surface tissue are ruined, either collapsed or burst. This applies to its outside layers as well, which is why the blob of the blobfish (as usually depicted) makes me wince. The creatures of this type usually die instantly upon these effects.

      To get to your question, the blobfish doesn’t lack muscles; they are merely minimal. Furthermore, the original action of muscle is antagonistic – remember, muscles significantly pre-date all hard-structure features, e.g. skeletons. So it’s not like the muscles need hard substrate to do their job – obviously that’s not the case for many, many animals anyway. Think of all skeletons (exo, endo) as add-ons to this muscle-vs.-muscle arrangement throughout an animal’s body.

      The next and related topic is what all the glop is doing – the answer is simple, it’s a different means of maintaining buoyancy from the most-common fish physiology of the swim (or gas) bladder. H’m – evolutionarily, that’s not quite right, because the blobfish is a member of the group which has the swim bladder (which is most living fish), so what we’re looking at is a buoyancy mechanism which originally augmented that method, and has possibly replaced it. (I do not know whether the blobfish has a working swim bladder or not.) And with such light and yet bulky body mass material, the muscles to move it about don’t have to be very strong, – and remember, they work against each other, so it’s merely equivalence that’s called for, not raw muscle mass and strength.

      The details of these features are beyond my immediate knowledge, but can be easily discovered with the right vocabulary for inquiry. I’d like to know more about what proteins make up the glop, and which muscle groups are genuinely not doing anything (or much).

      Oh yeah, the fins. Fins don’t propel fish through the water; they’re not oars. The forward motion is imparted via alternating the right-and-left of an S-shape, which, given water pressure, zips the animal forward shockingly efficiently. This is how fish we’re familiar with appear almost to teleport from place to place, at very short distances. Fins are used more like rudders to give direction to the movement.

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    • Ding ding! Meaning, you win, ’cause that’s the big mystery of the bunch. Barring some highly specific emails to people beginning with sentences like, “hey, been a long time since grad school,” I am reduced to generic sources which are appalling me in their bland meme-driven nonsense. I did find that they strew bezillions of pink eggs on the ocean floor and that an adult fish guards them, which makes their reproduction … totally ordinarily fish-ish.

      I also note some contradictions in descriptions of its diet. One version, which usually accompanies the silly “no muscles” phrase, claims it bobs there in the water doubtless with a puzzled expression as things float into its mouth. Another cites a number of crustacean species, and not brine shrimp either, but sea pens, crabs, and lobsters … which at least hints at something data-driven and more importantly, implies proactivity and competence to catch the little buggers, who are not noted for sluggishness.

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      • I am enamored of the idea that the blobfish is an apex predator of the deep sea bottom, and someday when humans appreciate its’ true ferocity we will regret subjecting it to both physical depressurization and internet meme-ification. But the data I found can’t support that.

        One link I followed characterized them as members of the “obscure” fish family Psychrolutidae, and seemed to think the key aspects of this family are a large head and a small, flat tail. Would you say this family attribution is likely to tell us much about “who it is”, or even “how it got this way”? If so, what does it tells us and/or how does it tells us that?

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  2. OK, this is interesting – by searching “Psychrolutes marcidus” at fishbase.org, I learned that the blobfish has a “Phylogenetic diversity index” of 0.5005 (where 0.5 = low uniqueness and 2.0 = high uniqueness). If the measure means anything and I’m interpreting it correctly, the post title is phylogentically dead-on – there’s nothing unique about a blobfish. Is that right? I mean, I guess I can buy the idea that odd visual side-effects of decompression + internet “has no muscles” nonsense creates a false sense that something must be odd about this creature. But that still seems REALLY not-unique … is the answer to “who is it” really “just another fish”?

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    • Cool, you looked something up! And found the right thing, too. I was just composing this at the time:

      “Obscure,” my Aunt Sass! … give me strength … all right, who is this, then? A taxonomic eye can derive perhaps more heft from those lists of bastardized Latin and Greek …

      Let’s look at the Class level, a designation at the level of Mammalia, Aves, and any other major group of vertebrates. The relevant Class is Actinopterygia, the most familiar and common type of fish: a bony skeleton, fan-like limbs. Its ancestral lungs (homologous with ours) have become a swim bladder.

      Inside it are a bunch of Orders, of which there are many. This group is huge; it’s the single biggest and most species-diverse category in all of Vertebrata. Think of all the mammals. Think of all the dinosaurs even in the broad popular sense of that term. Actinopterygia is bigger and more speciose than either.

      One of the Orders – a big one – is Scorpaenoformes, a very broad designator defined by a facial feature not worth talking about much. Just bear in mind it’s not some small corner of rayfin-fish-dom, it’s a “type” that represents a whole lotta fish. Inside it, among many subdivisions, is the Suborder Cottoidea, the sculpins. These are big-headed, flat-tailed fish usually under a foot long, notable for their predatory roles along the ocean bottom, at a wide range of depths per species. It’s made up of eleven Families, the biggest of which is the Cottidae, with 258 species, and most of which are pretty small with less than ten species each.

      Psychrolutidae (fathead sculpins) is one of the cottid Families that’s pretty big, subdivided into nine genera containing in total 40 species. One of these genera, genus Psychrolutes, has 11 species, of which our topic of the day is one.

      So back up – this is a major, in fact the major vertebrate group, one of the biggest subdivisions within it, and continuing into smaller and smaller categories, each one being pretty speciose compared with the other groups in its level. In other words, the very opposite of “obscure.” It so happens that they vary greatly, per species, in terms of ocean depth, and our guy is the “deep one” of the bunch.

      Got me? This taxonomic and phylogenetic perspective matters a lot. Our blobfish is a totally ordinary fish which happens to be ecologically a bit distinctive from its close relatives, and therefore has a few interesting ecomorphological features – much like the desert hopping mouse has very efficient kidneys, much like the night monkey has big round spooky eyes. This isn’t exotic; it’s both normal and cool.

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