The rootmouth jellyfish is unique in its biological makeup as being the only member of its genus. Belonging to the family Rhizotomatidae, it is a large cnidarian that can grow to sizes comparable with that of a human. Its smooth surfaced bell and large mouth are some of its most distinguished features. Despite its size, Eupilema inexpectata – as it is known by its scientific name – is equipped more for consuming large quantities of microscopic food. This jellyfish is more commonly found in the southern hemisphere.
Like other jellyfish, E. inexpectata features a rounded, dome-shaped bell, and somewhat resembles a large mushroom. Its large tentacles together with the bell assist the jellyfish in propelling itself through the water, and the smooth-surfaced bell features no tentacles. Unlike most species of jellyfish, the root mouth jellyfish is much larger, reaching diameters that can exceed 1 meter. Also one of the features it is most known for it the large manubrium or mouth, meant to facilitate an easier acquisition of food. The mouth has numerous microscopic holes leading straight to its stomach that are responsible for making the jellyfish’s feeding cycle easier.
The place where the rootmouth jellyfish is most prevalent is South Africa. Unlike most species it is not as widespread, however, its localized distribution is associated with the entire South African coast. From one side to the other, you can find root mouth jellyfish of varying sizes at depths that are not as large as the ones where other species can be found. These jellyfish can swim closer to the surface, up to about 35 meters below sea level.
The genus Eupilema only features this single species, and it belongs to a larger order of jellyfish known as Rhizostomae. These jellyfish have no additional structures around the bell – such as the tentacles some species possess – but, instead, they feature eight oral arms that are branched out in order to facilitate the gathering of food. This order is quite large, with no less than 10 different families, each featuring several genera, however, the root mouth jelly is unique among them in its behavior, appearance, size and shape. An interesting fact about the rootmouth jellyfish is that it can often be found swimming along with large numbers of fish, which use its bulk to avoid and attempt to hide from their predators.