The BBC did not mention a species name, and the infographic below suggests that it’s an unknown. On the CRUST-L listserver, however, the general agreement was that this was Alicella gigantea, the biggest known amphipod. This is a deep water, rarely seen species.
This infographic prompted Rebecca Watson to quip:
If you’re wondering how big Superprawn was, this image clearly shows he was about half the size of New Zealand.
Not a heck of a lot is known about its biology, though all signs point to it being a scavenger. The few times its been photographed, its often been on bait. Its mouth is shaped to take in large bites of food, and about 90% of its innards consists of the midgut. Many of the specimens have been retrieved from the guts of fish, so these animals aren’t big enough to escape predators.
Alicella gigantea is collected in the Atlantic, too. It’s thought that they are the same species, but to my knowledge, no DNA work supports that. Several people on the Crustacean discussion list were explicitly skeptical of the idea that something this wide-ranging would be the same species. Indeed, one person noted that differences between the Atlantic and Pacific populations were noted some time ago.
De Broyer C, Thurston MH. 1987. New Atlantic material and redescription of the type specimens of the giant abyssal amphipod Alicella gigantea Chevreux (Crustacea). Zoologica Scripta 16(4): 335-350. DOI: 10.1111/j.1463-6409.1987.tb00079.x
Barnard JL, Ingram CL. 1986. The supergiant amphipod, Alicella gigantea Chevreux from the North Pacific Gyre. Journal of Crustacean Biology 6: 825-839.