Last year, I wrote about the world’s biggest animals – and jellies topped the charts. Now, we know jellyfish dominate the opposite end of the animal spectrum too. A jellyfish was just declared the smallest animal in the world.
These minute beings were so problematic when they were first discovered living embedded in the tissues of fish, taxonomists of the 1880’s scratched their heads and named them for how mixed up they felt. The myxozoa were strange little parasites, just a few cells in size. Perhaps, like many parasites, they were protozoans like amoebas.
Peering closer, scientists noticed something exceptional. One of the few myxozoan cells is cyst that can expel (or fire?) its contents, maybe used to fasten the parasite to the host’s body. The reminded the scientists of something they’d seen before: a jellyfish stinging cell. In the 1930’s, Robert Weil, an expert on jellyfish stinging cells, examined the myxozoan cysts and said they must belong to a jellyfish too.
Oh, there were mxyozoan-as-jellyfish skeptics. Jellyfish have complicated bodies with mouths, stomachs, ovaries, tentacles, eyespots, touch plates. Myxozoans don’t have have any of those things. They hardly have a body at all. How could something so degenerate be a jellyfish?
Around 1995, a clue was found. DNA analysis showed that myxozoans were not protists after all. They occupied a branch on the animal tree of life. The question still remained, which one?
Last month, scientists from Kansas, Harvard, and Tel Aviv confirmed what jellyfish researchers long suspected. Myxozoans are jellyfish.
Their analysis found that not only do myxozoans have and incredibly reduced body structure, their genome is diminutive too; among smallest of any known animal. Which makes sense. There’s no need to haul along genes that code for body parts or for systems that grow body parts or communicate between body parts if you don’t own any body parts. Of course, it was some super speedy evolution that made such cleansing of unnecessary genes possible. I think there’s more great science to be learned about how that occurred.
The idea of cleaning out seems to be having resonant moment. There’s been a flurry of interest in simplifying, in clearing out the refuse, in reducing what’s unnecessary. The huge success of Mary Kondo’s book about the Japanese art of tidying has us atwitter with questions of which items in our lives bring happiness–and which don’t.
Myxozoans have no qualms. They’ve have taken the idea of tidying to the extreme. About all that remains in their bodies is the stinging cell and the ability to reproduce. But really, that’s the fundamental core of what a jellyfish is. While parasitism has its heebie jeebie quality, there’s a piece that’s beautiful too. Myxozoans are jellyfish, distilled to their essence.
Last month, something happened that I know for certain brings me happiness. Thanks to my wonderful agent Mollie Glick and my new editor Courtney Young, the book I’ve been blogging about here for almost two years, Spineless, was purchased. It will be published by the exceptional and unparalleled house, Riverhead Books, which publishes the likes of Elizabeth Gilbert, Paula Hawkins, and Lauren Groff, not to mention Etgar Keret and Sarah Vowell! Much more to follow here and in other social media. But for now, this moment is joy, distilled to its essence.