Microscopic jaws

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In the last post, we saw a compliant little rotifer getting on with the pressing activity of collecting food. In this next bit of footage, we can see the very same rotifer, but obligingly it has changed its position a little so we can see more of its body. About one-third the way along the body is what we want to look at, because it’s how these tiny animals ‘chew’ their food. You should be able to see a structure opening and closing. This, if you can see it is the rotifer’s jaws, more correctly known as the mastax. For an animal so small and with only around 1,000 cells in its entire body, this structure is amazingly complex; an assemblage of muscles, ligaments and toothed plates (trophi) all working together to macerate the food before it’s digested. Below the video there is a SEM of these trophi teased out of a rotifer and lovingly prepared by Martin Sørensen, an expert on these animals. The SEM gives an idea of the hidden complexities of this miniature world.

Rotifer feeding: Part 1 from Ross Piper on Vimeo.