Phronima is a genus of small, deep sea hyperiid amphipods of the family Phronimidae. It is found throughout the world's oceans, except in polar regions.[1] Phronima species live in the pelagic zone of the deep ocean. Their bodies are semitransparent. Although commonly known as parasites, they are more technically correctly called parasitoids.[2] Instead of constantly feeding on a live host, females attack salps, using their mouths and claws to eat the animal and hollow out its gelatinous shell.[3] Phronima females then enter the barrel and lay their eggs inside, then propel the barrel through the water as the larvae develop, providing them with fresh food and water.[3]
It is sometimes thought to be an inspiration for the fictional xenomorphs.[4] [5]
Phronima species possess unique compound eyes adapted to detect blue-green wavelengths of light, which are prominent in the bioluminescent flashes of potential prey and predators. These specialized visual adaptations aid Phronima in navigating the dim mid-ocean environment, where bioluminescence serves as an important ecological signal
The genus Phronima contains these 10 species:
7. Osborn, K.J., Baldwin Fergus, J. (2020). Hyperiid Amphipod Adaptations to Mid-Ocean Environments. Smithsonian Ocean. National Museum of Natural History.