Due to its bright red stomach that bears a resemblance to the Cross of St George, the jellyfish was given the name Santjordia pagesi by scientists.
During his research on the Sumisu Caldera, a highly unusual species of medusa was discovered at a depth of 812 meters, alongside the scientific team that discovered the creature, the creature has been seen only twice in the area.
Santjordia pagesi, also known as Medusae, is a newly described species of medusa. It is a jellyfish that is approximately 10 cm in diameter and has a red stomach that looks like the Cross of St George when viewed from above. Medusae are a type of jellyfish that swims freely, but with a reduced stalk.
An international team of researchers, which included a Brazilian scientist with assistance from FAPESP, conducted an international study that is described in an article published in the journal Zootaxa.
The scientist named André Morandini, who holds the position of director at the Center for Marine Biology (CEBIMar) at the University of So Paulo, is the last author of the article.
FAPESP partnered with Morandini for three projects (10/50174-7, 11/50242-5, and 13/05510-7) to provide him with funding while conducting his research.
The other authors are from JAMSTEC and OIST, both based in Japan.
The St George's Cross Medusa, as it is referred to, is said to exist exclusively in the Sumisu Caldera located in the Ogasawara Islands, which are approximately 460 km south of Tokyo. The caldera is a deep-water volcano with a hydrothermal active activity, measuring about 10 km in diameter and 812 m in depth.
Morandini pointed out that the species is relatively small compared to other deep-sea medusae, and the bright red color of its stomach likely relates to its ability to capture food.
Bioluminescent organisms emit light from their abdomen, preventing predators from detecting their predation.
The medusa was classified as a part of the Ulmaridae family of jellyfish, with the species name pagesi chosen to honor the late Dr. Francesc Pagès, a well-known scientist who researched jellyfish and conducted taxonomy in Barcelona.
Each time a new species is discovered, they gather several specimens, but S. pagesi is a rare ape that was so difficult to collect that it was too difficult to describe, so although the researchers observed an other species nearer to the body, they expect further surveys of the deep sea to find more members of the group.
The specimen was discovered in 2002 while diving in the Sumisu Caldera, a unique species that is only found in scientific expeditions using this type of equipment. No other specimens were recovered until 2020, when the KM-ROV filmed, but failed to recover another specimen of the same species.
Morandini explained that the decision was made to highlight the species present at the site in order to publish the description and highlight the potential for commercial development of minerals on a mineral-rich substrate. "Research is not feasible in such places without partners who have interests of this kind.
The researchers hypothesised that S. pagesi, a species that is not closely related, may have an arsenal of venoms that are not present in the known world.
The Santjordiinae, a new subfamily of the ulmarid scyphomedusae, and its description for the Ulmaridia pagesi gen. from the Sumisu Caldera in Ogasawara Islands, Japan, have been presented in a research paper published in Zootaxa, DOI 10.11646/zootaxa.5374.4.5.