Large shrimp-like crustaceans, some as long as 13 inches, have been found 4 miles deep in the ocean off the coast of New Zealand, researchers say.

Researchers from the University of Aberdeen in Britain say the creature, dubbed a supergiant, is a type of amphipod, which are normally around an inch long.

These creatures, discovered at the bottom of the Kermadec Trench, were more than 10 times bigger, researchers said.

"It's a bit like finding a foot-long cockroach," Alan Jamieson of Aberdeen's Oceanlab said. "I stopped and thought: 'What on Earth was that?' This amphipod was far bigger than I ever thought possible."

Amphipods have been found living in large numbers at the bottom of ocean trenches, deep, narrow valleys in the sea floor that can be as deep as almost 7 miles.

The name "supergiant" was first coined after large specimens were caught in the 1980s off the coast of Hawaii. Those specimens are dwarfed by the new ones.

"For such a large and conspicuous animal to go unnoticed for so long is just testament to how little we know about life in New Zealand's most deep and unique habitat," Ashley Rowden of New Zealand's National Institute of Water and Atmospheric Research said. "It just goes to show that the more you look, the more you find."