New 24-eyed box jellyfish species discovered in China

A team from Hong Kong Baptist University (HKBU) has discovered a new monster of the deep - a box jellyfish with 24 eyes found in the Mai Po Nature Reserve in Hong Kong.

The new jellyfish species, which belongs to the family Tripedaliidae, was named Tripedalia maipoensis by the research team, led by Professor Qiu Jianwen from the Department of Biology at HKBU. It is the first discovery of a new box jellyfish species from the waters of China and the find adds a fourth species to the Tripedaliidae family.

With collaborators from WWF-Hong Kong, Ocean Park Hong Kong and the University of Manchester, the team collected the jellyfish samples from a brackish shrimp pond in the Mai Po Nature Reserve during the summers of 2020 to 2022, and they found that the samples contained a new species.

Professor Qiu said: "We named the new species Tripedalia maipoensis to reflect its type locality - where the new species was first found. Although it is currently known only in Mai Po, we believe that this species is also distributed in the adjacent waters of the Pearl River Estuary as the gei wais are connected to the estuary through a tidal channel."

The jellyfish has a transparent and colourless body with an average length of 1.5 cm. There are three tentacles that are up to 10 cm long at each of its four corners. Pedalia, a flat pedal-shaped structure at the base of each tentacle that looks like a boat paddle, allows box jellyfish to produce strong thrusts when they contract their bodies. They can thus swim faster than other kinds of jellyfish.

Like other box jellyfish, Tripedalia maipoensis has 24 eyes. The 24 eyes are equally divided into four groups, and each group of six eyes.

Professor Qiu added: "Our discovery of Tripedalia maipoensis in Mai Po - a relatively well-studied area in Hong Kong - highlights the rich diversity of marine life in Hong Kong and even the whole of China."