Bathykorus bouilloni is a species of jellyfish found in the Arctic Ocean at depths of 2,600 feet below sea level and extending to roughly 8,200 feet below sea level. Its range extends around Greenland and the north of Canada.
This jellyfish is a recently discovered specimen that was first described in 2010. It is the only species within its genus, Bathykorus. Its genus name is derived from the Greek words bathy, meaning “deep” and korus, meaning “helmet,” which refers to the depth at which the species is found and the shape of its bell (body). The specific name is in honor of marine biologist Dr. Jean Bouillon (1926-2009).
This is a small gelatinous jellyfish that grows to around 0.8 inches in width. It is transparent and pale blue, with 4 primary non-contractile tentacles set high above the margin of the dome-shaped bell. There are 4 short secondary tentacles lower down near the undulating margin. The central circular mouth is located on the oral surface leading to a gastric chamber out of which lead twelve gastric pouches, three in each quadrant. The primary tentacles are solid and usually held above the bell in the direction of locomotion.
Because of the depths at which this species is found, it is not possible to visually observe it where it occurs. The initial observations were made by a remotely operated vehicle. It has also proven difficult to study because they tend not to survive capture by netting. However, gentle suction has successfully led to the capture of some individuals, but the individuals only survived when immediately transplanted into tanks with similar conditions where it lives, and then only for a week or so.