Jellyfish with bright red cross discovered in remote deep-sea volcanic structure

Scientists say they have discovered a new species of Medusae — a type of free-swimming, umbrella-shaped jellyfish. The sea creature — which was first spotted in 2002 in a deep-sea volcanic structure in ocean waters south of Tokyo, Japan — has a bright red “X” on its stomach.

The findings were published this past November in the scientific journal Zootaxa. The researchers named the marine animal “Santjordia pagesi” after the Cross of St. George because of the striking X. The “pagesi” suffix was given in honor of the late Dr. Francesc Pagès, a jellyfish taxonomist.

“The species is very different from all the deep-sea medusae discovered to date,” scientist André Morandini said in a news release last week from the São Paulo Research Foundation. “It’s relatively small, whereas others in this kind of environment are much larger.”

As for the unique red cross, Morandini said it “probably has to do with capturing food.”

S. Pagesi, which has 240 tentacles, was spotted and collected off Japan’s Ogasawara Islands over twenty years ago with a remote-operated vehicle — the only way to research the inhospitable waters. In 2020, scientists spotted another specimen of the X-marked marine animal in the same area, but were unable to collect it. 

While the discovery of a new species usually requires the collection of more than one creature, this Medusae was given a name and description based on the capture of just one because of how rare it is, Morandini explained. 

“We opted to publish the description and call attention to the species that are present at the site, which has a substrate rich in minerals and the potential to be commercially developed,” the scientist said in the news release. “Unfortunately, research can’t be conducted in such places without partners who have interests of this kind.”