New Scientist plumbs the depths in search of foot-long white shrimp-like creatures that might be one of the most populous creatures on the bottom of the ocean, but about which we know very little
The crustacean, known as Alicella gigantea, has the distinction of being the world’s largest amphipod, growing up to 34 centimetres in length. But this “supergiant”, living on the floor of the deep ocean, hasn’t been easy to find. “Because [the deep sea] is so hard to get to, it’s been undersampled for so long, and we’re finally playing catch up,” says [University of West Australia researcher Paige] Maroni.
She and her colleagues collected 75 records of A. gigantea, stretching back to the first collection of a specimen in 1899. These included finds in the Pacific, Atlantic and Indian oceans. They also used DNA sequences from specimens across all three oceans to reconstruct genetic relationships among different populations.
They found the specimens had been collected from depths ranging from 3890 to 8931 metres. They estimate that about 59 per cent of the sea floor falls within this range. The genetic data also suggested the specimens, although distributed across this vast area, all represented one genetically similar species.
—
You can read more of the big amphipod research here, in Royal Society Open Science.