The photo you see above is a culture of Henneguya Salminicola swimming under a microscope. Its unique stinger cells (the ones that look like alien eyes) are central to why the species was able to survive without getting overly involved in evolution.
Henneguya Salminicola reproduces by sinking its spores into the flesh of victims (which are mostly fish, so you can relax). That being said, the organism can live on land as easily as it can live in water because it is the only known animal on Earth that doesn’t engage in any form of breathing.
The discovery of this specimen surprised researchers as all other multicellular animals on this plant have some sort of functioning respiratory system. The fact that H. Salminicola does not have a mitochondrial genome is peculiar. This information was published in the Proceedings of the National Academy of Sciences journal after substantial genomic and microscopic analysis of the microscopic critters.
The mitochondrial genome is a small yet very important portion of DNA stored in an animal’s mitochondria which allows it to undergo respiration.
Though finding an animal that doesn’t breathe is a biological first, scientists believe this peculiar feat fits the species quite well. H. Salminicola is a parasite from the myxozoa class, meaning it belongs to a group of simple, microscopic swimmers that closely resemble the jellyfish. Experts believe they might have looked like jellyfishes before, but eventually evolved.
According to Dorothee Huchon, an evolutionary biologist from Tel Aviv University in Israel and the study’s co-author, “they have lost their tissue, their nerve cells, their muscles, everything.” And to top it all off, she added, “now we find they have lost their ability to breathe.”
As if being an animal that doesn’t have any mitochondrial DNA isn’t interesting enough, the research team revealed that H. Salminicola has spores that glow green under a fluorescent microscope.
In the science world, this devolution phenomenon is referred to as “genetic downsizing,” and it isn’t always good for the species. But for parasites like the H. Salminicola, having the ability to reproduce whenever they want with quick turnaround is a huge advantage. Myxozoans have the smallest genomes of the animal kingdom, making them simple but effective when it comes to breeding and feeding. Some species are so effective, in fact, that they can infect and wipe out entire fishery stocks in a matter of months. Commercial fishers don’t see H. Salminicola as a threat since they are relatively benign. However, other species from its family aren’t taken so lightly.
The H. Salminicola parasite pops out of a fish’s flesh with white, oozing bubbles. At this stage, it has the appearance of unicellular blobs. Experts refer to this as “tapioca disease,” for obvious reasons. When viewed under a microscope, the parasite’s spores reveal more complexity, with a bluish sperm cell, two tails, and those alienesque eyes.
Don’t be fooled though – the eye-like structures are actually stinging cells. These don’t inject venom but they do help H. Salminicola latch onto a host. This is a talent the species did not evolve away from, despite their significant evolutionary downsizing over the years.
Huchon claims that “animals are always thought to be multicellular organisms with lots of genes that evolve to be more and more complex. Here, we see an organism that goes completely the opposite way. They have evolved to be almost unicellular.”
A question that remains unanswered by experts is, how do these animals acquire energy without breathing? Huchon’s theory is that H. Salminicola has proteins that import ATP or something similar, just like other parasites. Experts are undertaking further research to uncover how the parasites are able to survive without a respiratory system.