Supergiant crustaceans could live across half the deep-sea floor

A recent study suggests that a giant crustacean, resembling a large white shrimp, known as Alicella gigantea, may be more prevalent in the deep sea than previously believed, potentially inhabiting a significant portion of the ocean floor.

Paige Maroni, a researcher at the University of Western Australia, notes that deep-sea species like Alicella gigantea have often been labeled as rare due to the challenges of exploring these remote environments. However, new findings indicate a greater interconnectedness among these species than initially thought.

Alicella gigantea holds the title of the world’s largest amphipod, reaching lengths of up to 34 centimeters. Despite its impressive size, this “supergiant” crustacean has been elusive to researchers due to the difficulties in accessing deep-sea habitats. Maroni explains, “Because [the deep sea] is so hard to get to, it’s been undersampled for so long, and we’re finally playing catch up.”

In their study, Maroni and her team compiled 75 records of Alicella gigantea dating back to 1899, with specimens found in the Pacific, Atlantic, and Indian oceans. By analyzing DNA sequences from specimens across these three oceans, they were able to uncover genetic relationships among different populations.

The researchers discovered that specimens of Alicella gigantea were collected at depths ranging from 3890 to 8931 meters, covering an estimated 59% of the sea floor. Despite the vast geographic distribution, the genetic data indicated a high degree of genetic similarity among the specimens, suggesting a single species occupying a larger habitat range than previously assumed.

Maroni emphasizes that the 59% estimation based on depth represents a maximum potential habitat extent, shedding light on the broader distribution of these supergiant crustaceans across the deep sea.