Field of Science

Deciphering protist shapes

A while ago, while rigorously procrastinating, I came across a slightly odd tiny freshwater flagellate that was sufficiently morphologically non-straightforward it lent itself well to 3D reconstruction/sketching practice. Figuring out cell shape from micrographs isn't as easy as it looks – for one thing, the bloody cell is three dimensional, while the images are flat and further complicated by DIC optics – and thus a very fun exercise! And then, once you've got a cell shape in your head, you have to figure out a way to draw it out for others to see. I still suck, but the sketches at the end looked kinda pretty together with the micrographs, so here they are:

I still have no idea what this thing is. Acts vaguely ancyromonad-like, but may well be a glissomonad or something else entirely. Pretty positive it's biflagellated. Probably nothing too earth-shattering (and may well be well-known by everyone but me), but if anyone has some sort of research interest in this thing, let me know – don't have time to deal with it myself. Not that I'm likely to find it again... Here's the pics and videos:

video video


  1. Ill take you at your word that it is biflagellated, I didn't see it though. My first thought was a flagellated spore of the chytridomycota.

    Also, Ive been meaning to thank you for bringing the 'A Tree of Eukaryotes' figure to my attention. I started using it this last semester in my Eukaryotic Microbiology class to give students a sense of where the organisms we were discussing lie evolutionarily (at least at present). That figure is much better and useful than figures I have used previously.

  2. The 2nd flagellum is barely visible in a couple of the movies – the uploading screwed up the quality, and I have a couple I didn't bother putting up here, since most people don't care that much. Counting flagella not as easy as it looks sometimes.

    Chytrid zoospores and animal sperm move in a very characteristic way: the flagellum is quite stiff, and points backwards and, as far as I know, doesn't glide. In fact, you can tell gametes apart quite easily because they generally suck at swimming. I have some videos of chytrid zoospores and sponge sperm lying around somewhere...
    This critter seems to be something resembling Metromonas sp.

    And thanks for using the tree, glad someone finds it useful =D Which reminds me, need to release a new version soon.

    You guys have a euk micro course? Would be interested in talking to you about it...

  3. Perrty.

    Is there any general way of trying to work out the 3D structure of things under a 'scope?

    At the end of last year I found my self inspecting snail gut contents, and for someone used to macrosopic animals it was a whole new world. Took me days to realise that three different things I'd been drawing and counting in different samples were actually the same species of pollen in three different planes.

    Is there any hope for someone that inept, or do I just need to put in the hours and get a feel for these things?

  4. Psi, happy to discuss the course with you anytime. Hit me up at my gmail account dadavis221 at


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