Bathynomus giganteus is a species of aquatic crustacean, of the order Isopoda. It is a member of the giant isopods (Bathynomus), and as such it is related—albeit distantly—to shrimps and crabs. It was the first Bathynomus species ever documented and was described in 1879 by French zoologist Alphonse Milne Edwards after the isopod was found in fishermen's nets off the coast of the Dry Tortugas in the Gulf of Mexico.
The Bathynomus genus is benthic and abundant in cold waters with a depth of 310–2140 m in the West-Atlantic, including the Gulf of Mexico and the Caribbean. It was the first species of Bathynomus to be described and historically it was reported from other oceans, but these are now recognized as other closely related species. The unusually large size of Bathynomus has been attributed to an effect called deep-sea gigantism, where invertebrates living in cold deep waters tend to grow larger and have longer lifespans.
Physical description
thumb|left|A frontal view of Bathynomus giganteus, showing its large, highly reflective compound eyes
Like most crustaceans, the body of Bathynomus giganteus is divided into three distinct regions; a head (cephalon), a thorax, and an abdomen (pleon). When light bounces off a highly-reflective layer called the tapetum lucidum at the back of their eyes, it makes them appear to glow. an individual claimed to be 76 cm long has been reported by the popular press, but the largest confirmed was ca. 50 cm.
Reproduction
Bathynomus reproduce via egg-laying. Mature females develop a pouch known as a marsupium, where the eggs are stored until the young are ready to emerge as miniatures of the adults, known as manca, completely bypassing a larval stage. Mancae can reach lengths up to 60 mm and are characterized by their lack of the seventh pair of pereiopods. The females of B. giganteus, while being so many times larger than females of other isopods, carries approximately the same number of eggs in its marsupium.
Aquaculture
thumb|209x209px|2.62kg specimen found in [[Hanoi]]
Giant isopods are not usually fished commercially. However, other Bathynomus species can be found in the occasional oceanside restaurant in northern Taiwan, where they are boiled and typically served with rice.