The animal world is full of oddities that sometimes chill your spine. Some fish are parasitized by small crustaceans that feed on blood. After settling in, the parasite becomes a full-fledged organ of the animal.
“Micro-CT scanning is basically a 3D X-ray that allows researchers to visualize the internal anatomy of organisms without the need for dissection,” Evans explained to Newsweek.
“So far we’ve scanned nearly 200 species. To compare shapes between specimens I placed digital landmarks at different points along the skull to allow for detailed comparison. I found the parasite while trying to place digital landmarks inside the mouth cavity of the fish.”
Mondays aren't usually this eventful. I found a tongue-eating isopod (purple) in one of our wrasse scans this morning while digitizing it. These parasites attach themselves to the tongues of fishes and effectively become the new tongue…horrifying #backdatwrasseup pic.twitter.com/axlraUrh8W
— Kory Yanfei (Evans PhD) (@KoryYanfei) August 10, 2020
The Blood-Drinking Parasite In The Mouth
It was during a project to study the structure of the skulls of labrids, a family of fish with 500 species, that the computed tomography that the parasite was identified. It belongs to the isopod family which is known to live in the mouths of many species of fish. Once established in its host, the isopod uses the latter’s blood vessels for food.
The species Kory Evans discovered, Cymothoa exigua, goes even further. The tongue of the fish atrophies as the isopod feeds on its blood, so it is the parasite that serves as the animal’s tongue. It is the only known example of a parasite which performs the function of an organ of its host. Parasitized fish do not seem to suffer unduly from the presence of the parasitic crustacean, but when they are invaded by several individuals, they may have difficulty feeding.
What's your fave #UglyAnimal? #CymothoaExigua the fish tongue parasite!! @WildscreenFest @UglyAnimal @WWF_UK pic.twitter.com/FUfSHJlaGA
— Patrick Aryee (@PatrickAryee) October 16, 2014
The species Kory Evans discovered, Cymothoa exigua, goes even further. The tongue of the fish atrophies as the isopod feeds on its blood, so it is the parasite that serves as the animal’s tongue. It is the only known example of a parasite which performs the function of an organ of its host. Parasitized fish do not seem to suffer unduly from the presence of the parasitic crustacean, but when they are invaded by several individuals, they may have difficulty feeding.
