Most bioluminescent octopus
red deepwater
United States (eastern USA)

Unlike squids, which include many bioluminescent species, the only significantly bioluminescent species of octopus is a red deepwater species from the eastern USA called Stauroteuthis syrtensis. Its bioluminescent ability remained unknown to science until 1997, when Edith Widder (USA) of Harbor Branch Oceanographic Institution in Fort Pierce, Florida, USA studied a live specimen captured in the Gulf of Maine; when dark, the specimen presented a row of sucker-like structures running the length of each of its tentacles glowing blue-green and emitting most light at 470 nanometres (a wavelength that travels well under water). Researchers now believe that these structures are suckers that are no longer used by the octopus as grasping organs like those of other octopuses, but have instead evolved into light-emitting photo-lures, which can flash on and off, attracting prey near enough to be seized by its tentacles.