Scientists discover new jellyfish species in waters off Alicante in Spain

Scientists discover new jellyfish species in waters off Alicante in Spain Lisa Lock Scientific Editor Robert Egan Senior Editor The Mediterranean Sea still holds species unknown to science. One of them is Copula lucentia, a tiny jellyfish measuring just a few millimeters. Discovered off El Campello, in Alicante, it was formally described in 2024 by a research team at the University of Alicante (UA) Marine Laboratory in Dénia, which forms part of the university's Ramón Margalef Multidisciplinary Institute for Environmental Research. The finding makes Copula lucentia only the second box jellyfish species documented in the Mediterranean, following Carybdea marsupialis, described by Linnaeus in 1758. It shows that even one of the most thoroughly studied seas on the planet still has biodiversity to reveal. Ranging from 1 to 7 millimeters (0.04 to 0.28 inches) in size, Copula lucentia was identified from specimens collected between 2016 and 2018. The description, published in the journal Marine Biodiversity in 2024, combined morphological studies with genetic analyses carried out in collaboration with international specialists. Eva Fonfría, a researcher at the University of Alicante and lead author of the study, explained that the discovery was made during a sampling campaign. "At first we were surprised because it was very small for that time of year, and it had certain morphological features that didnt fit," she recalled. These anomalies prompted the team to analyze the specimens and compare them with known species. The results confirmed that, although the organism belonged to the genus Copula, its distinctive features warranted classification as a new species. A small jellyfish with an Alicante name The scientific name, Copula lucentia, refers to Lucentum, the Latin name for Alicante. To date, the species has been recorded only off El Campello, which makes this stretch of the Alicante coastline a key site for further research. "Finding a new species in the Mediterranean, where everything is so heavily studied, is very important," said Fonfría, who stressed the need to continue studying these organisms in order to understand their distribution and ecological role in marine ecosystems. Copula lucentia belongs to the box jellyfish group (Cubozoa), so called because of its cube-shaped bell. Its body is almost entirely transparent and has four tentacles, as well as small adhesive structures at the top that allow it to anchor itself to a variety of surfaces. The specimens studied were found at depths of less than 1.5 meters (4.9 feet), in an environment of rocky and sandy seabeds and seagrass meadows. Identifying the species required comparing several anatomical structures with those of Copula sivickisi, a related species found elsewhere in the world. Differences in the bell, together with genetic analysis, confirmed that the El Campello specimens belong to the same genus but constitute a distinct species. According to César Bordehore, senior lecturer in the Department of Ecology at the University of Alicante and coordinator of the UA Marine Laboratory in Dénia, the discovery is a "milestone" for marine research. "The fact that we have identified a second box jellyfish species in the Mediterranean shows how much we still have to learn about its biodiversity," he said. He also emphasized the need to expand research into small marine organisms, whose presence can easily go unnoticed. Questions still to be answered Despite the progress that its identification represents, many questions about the new jellyfish remain unanswered. Its reproductive cycle, its role in the food web and its ability to sting all require further investigation. Bordehore noted that, more broadly, there is a need to better understand the role of gelatinous organisms in marine ecosystems—particularly small ones such as salps, tintinnids and jellyfish—which can interact significantly with key areas such as fisheries. These tiny organisms prey on fish eggs and larvae. The same scientific team, led by Bordehore, currently coordinates the Sea4Future (A Sea for the Future) project. This Horizon Europe initiative brings together 22 partners from 12 countries to take an interdisciplinary approach, including the study of interactions with gelatinous organisms, to restore fish stocks in the Mediterranean while protecting vulnerable species such as turtles, dolphins and whales. Collaboration with the Oceanogràfic is central to this effort, as it is one of the world's leading centers for marine fauna recovery and for public awareness of the protection and restoration of marine ecosystems. Eight years after the initial collections, a sampling campaign organized with the Oceanogràfic in Valencia located and collected more than 200 specimens for further study. Some of these animals are being kept and displayed in the Medusa Lab at the Oceanogràfic, where work is underway to help them grow and to explore whether their life cycle can be completed under controlled conditions. Miguel Candelas, a biologist and head of jellyfish at the Oceanogràfic, explained that the specimens collected are still immature and that a key objective will be to bring them to sexual maturity so that they can reproduce. "This is a challenge for us because it is the first time this species has been kept in an aquarium," said Candelas, adding that the experience will broaden knowledge of the jellyfish's biological requirements. The partnership brings together the University of Alicante's expertise in marine ecology, taxonomy and genetics and the Oceanogràfic's experience in maintaining and breeding gelatinous organisms. Bordehore noted that joint work between the two teams makes possible research that would be difficult to carry out independently. The experience will contribute both to the study of Copula lucentia and to future research on other marine organisms. Specimens of Copula lucentia can now be seen for the first time in the Medusa Lab at the Oceanogràfic in Valencia. Because of their size, they are displayed under a magnifying glass, allowing visitors to observe their defining features up close and to see a species hitherto unknown to science. Provided by University of Alicante