Alien-like ambush predator encountered on the flanks of an underwater mountain in the world’s deepest ocean

Marine scientists using a remotely operated vehicle (ROV) to dive into and explore the deepest darkest reaches of the planet’s oceans have just had an encounter with a distinctly alien-esque species of jellyfish. The fantastic creature was spotted by researchers from the National Oceanic and Atmospheric Administration (NOAA), as they combed the face of the Enigma Seamount, a mysterious and little known feature within the Mariana Trench, east of the Mariana Islands near Guam in the western Pacific Ocean.

Identified as belonging to the hydromedusa family, within the genus Crossota, the colourful cnidarian was observed by a team of scientists operating the ROV Deep Discoverer at a depth of 3,700m. The jelly boasts bulbs of red and yellow lights that glow inside its bulbous body, while two sets of tentacles extend from the bell of the fish, a long set and a short set, leading the researchers to conclude that it is an ambush predator.

‘You’ll see that the long tentacles are even and extended outward and the bell is motionless,’ NOAA said in a statement. ‘This suggests an ambush predation mode. Within the bell, the radial canals in red are connecting points for what looks like the gonads in bright yellow.’

The dive was controlled from the research vessel Okeanos Explorer, as part of the 2016 Deepwater Exploration of the Marianas project, a three-cruise expedition conducted by NOAA to better understand the deep-water habitats in and around the Mariana Trench. Other discoveries made thus far include, according to the team: ‘stalked crinoids and primnoid corals, swimming polychaete worms, a cusk eel, Caulophacus sponges, cladhorizid sponges, a Munidopsis squat lobster, a beautiful hydrozoan jellyfish and at least two Nematocarcinus shrimp.’

The current leg of the mission will continue until 11 May, with the second cruise starting on 20 May and the third and final part beginning on 17 June and extending to 10 July. It’s possible to join live-streams of the expedition dives from 8.30am to 4.30pm Fiji Time (GMT + 12) on certain days.