Bathynomus giganteus

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.