A jellyfish just a few millimeters long, collected off Spain’s Alicante coast, has been formally described as a new species. A Phys.org report credited to the University of Alicante and edited by Lisa Lock says the finding makes it only the second box jellyfish species documented in the Mediterranean.
The species, named *Copula lucentia*, was identified from specimens collected between 2016 and 2018. The report says the description appeared in the journal *Marine Biodiversity* in 2024. Eva Fonfría, identified in the report as a University of Alicante researcher and lead author of the study, said the team first noticed the animals during a sampling campaign. Their small size and features that did not fit known species prompted closer examination.
Researchers compared anatomical structures with those of *Copula sivickisi*, a related species found elsewhere, and combined morphological work with genetic analyses. Differences in the bell, alongside the genetic analysis, supported classifying the specimens as a distinct species within the genus *Copula*. The reported size range is 1 to 7 millimeters.
The Mediterranean already had one documented box jellyfish species, *Carybdea marsupialis*, described by Linnaeus in 1758. The new record points to biodiversity that can remain unrecognized even in a sea that has been studied extensively. It does not, by itself, establish how widespread *C. lucentia* is or how common it may be.
So far, the species has been recorded only off El Campello, near Alicante. The studied specimens were found at depths of less than 1.5 meters, in areas with rocky and sandy seabeds and seagrass meadows. Its scientific name refers to Lucentum, the Latin name for Alicante. The limited known range makes the coast a focus for further research, but more observations would be needed to map the jellyfish’s distribution.
The report describes *C. lucentia* as a member of Cubozoa, the box jellyfish group, named for its cube-shaped bell. Its body is almost entirely transparent, with four tentacles and small adhesive structures at the top that allow it to anchor to surfaces. Important parts of its biology remain unknown: its reproductive cycle, ecological role, and ability to sting still require investigation. The report does not establish whether it poses a risk to people.
Follow-up work is underway with the Oceanogràfic in Valencia. Eight years after the initial collections, a sampling campaign organized with the aquarium located and collected more than 200 specimens, according to the report. Some are being kept and displayed in its Medusa Lab while staff work to help them grow and explore whether their life cycle can be completed under controlled conditions. Miguel Candelas, the aquarium’s head of jellyfish, said the collected animals are still immature; bringing them to sexual maturity so they can reproduce is a key objective. Keeping the species in an aquarium is a first, so this work is an effort to learn about its biological requirements, not evidence that its full life cycle has been replicated.
César Bordehore, a University of Alicante senior lecturer and coordinator of its Marine Laboratory in Dénia, said the discovery underscores the need to study small marine organisms that can go unnoticed. He also pointed to wider questions about gelatinous organisms in marine ecosystems. The report says Bordehore leads the Sea4Future project, a Horizon Europe initiative involving 22 partners from 12 countries that studies interactions with gelatinous organisms as part of work on restoring Mediterranean fish stocks and protecting vulnerable species. Those broader aims give the new jellyfish a research context, while its own ecological role remains an open question.