Sunday, 28 August 2011

Shells of microscopic crustaceans

  Arthropods always look cool because of their external shells that enclose their bodies. Microscopic arthropods are not an exception, and to my surprise they have very peculiar surfaces. The first pictures shows an ostracod, a tiny crustacean that is completely surrounded with a shell that makes it resemble a bivalve mollusc. They are normally very fast and it's totally impossible to see how they look like inside without destroying their armor, which I wouldn't do.
 The first picture is a stack, below you see a single frame.


  Here the focus is on the middle part of the body. Despite it looks like I had to stack lots of pictures into a single image to get the entire ostracod, I stacked only 8 pics to get the first image (the title one).

  Water fleas have even more amazing surfaces. Even though most of their bodies are encompassed with shells, their heads and antennae are outside. That's a ceriodaphnia. In my previous post I showed a close-up of it's eye.

  It's funny to see that in the microscopic worlds materials have different properties. It's hard to believe that a thin shell like that can survive heavy impacts, and under same proportions, but when scaled up in size, the shell would be very fragile. These shells are flexible, so when the animal moves its body you can see that the entire shell can bend and deform. It was a huge challenge in assembling the stack that's made out of 40 pictures because the flea was moving a lot and showing its flexibility in all possible ways.

  Unlike ostracods, water fleas have transparent shells and it's possible to see what's inside. The previous picture had higher magnification, that's why internal parts are not visible.


  Here I deliberately didn't cover the top, so the inner parts are visible. Basically, the legs are the only thing that are clearly seen under the shell. The legs have gills but it's not quite obvious on the picture. Water fleas normally use antennae to swim and legs to breathe.

  My last picture for this post may be fail to be spectacular but it's has one advantage - resolution. It's a stack of more than 500 pictures taken under maximum magnification lens - 100x with DIC illumination and the final resolution is around 14000x12000 pixels and I posted an eye of that Scapholeberis mucronata in the previous post. Just to make it clear, the picture of the head there was a 20% crop and you would need 7 x 12 (= 84) full HD screens to see the entire picture of the flea in full resolution. Despite it sounds like a masochistic work, it just took a couple of days of assembling (manually) and a couple of months to accept the challenge. I assembled it a month ago but posting only now.

  The strange bumps on its surface are vorticella ciliates that often attach to water fleas.

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