Hyperia medusarum is a species of pelagic amphipod crustacean that is commonly found in the open ocean. This species is a member of the family Hyperiidae, which consists of numerous species that are adapted to a life in the water column. The species is notable for its association with jellyfish, often residing within the bell or tentacles of these gelatinous invertebrates.
Description & Characteristics
Hyperia medusarum is a relatively large amphipod, reaching a maximum length of about 30 millimeters. The body is elongated and laterally compressed, with a distinct head, thorax, and abdomen. The head bears a pair of prominent compound eyes and a pair of antennae. The thorax is composed of seven segments, each with a pair of legs, while the abdomen has six segments. The last segment of the abdomen bears a pair of uropods, which are used for swimming and maneuvering. Hyperia medusarum, like many other amphipods, exhibits sexual dimorphism, with males typically larger than females.
Habitat and Occurrence
Hyperia medusarum is a truly pelagic species, meaning it inhabits the open ocean waters far from the coast. It is commonly found in the epipelagic zone, the uppermost layer of the ocean that receives sunlight. This species is also known to occur in the mesopelagic zone, a region of the ocean that exists between 200 and 1000 meters in depth, although it is less common there. Hyperia medusarum has a global distribution, being found in all of the world’s oceans.
Taxonomy
Hyperia medusarum belongs to the Class: Malacostraca, Order: Amphipoda, and Family: Hyperiidae. This family is characterized by its members’ adaptation to a pelagic lifestyle.
Feeding
Hyperia medusarum is a carnivorous species, feeding primarily on small invertebrates such as copepods, plankton, and larvae. It is also known to scavenge on dead organisms. While it frequently resides within jellyfish, its relationship with these invertebrates is not considered parasitic. Hyperia medusarum does not feed on the jellyfish itself, but rather uses the jellyfish as a means of transport and protection, as the jellyfish’s stinging cells offer some protection from predators.
Image References