The Mediterranean Sea still holds species unknown to science, and one of them is now formally described: *Copula lucentia*, a transparent box jellyfish measuring just 1 to 7 millimeters.

Specimens were collected off El Campello in Alicante between 2016 and 2018, and the species was formally described in 2024 in the journal Marine Biodiversity by a research team at the University of Alicante's Marine Laboratory in Dénia.

The name *lucentia* honors Lucentum, the Latin name for Alicante. To date the species has been recorded only off El Campello, making that stretch of coastline a key site for further research.

What makes the find remarkable is its rarity: *Copula lucentia* is only the second box jellyfish species documented in the Mediterranean, after *Carybdea marsupialis*, which Linnaeus described back in 1758.

Researcher Eva Fonfría, the study's lead author, recalled that the team was surprised because the specimens were very small for the time of year and had morphological features that didn't fit known species.

Comparison of anatomical structures with *Copula sivickisi*, a related species found elsewhere in the world, together with genetic analysis, confirmed the El Campello specimens were a distinct species.

University of Alicante senior lecturer César Bordehore called the identification a milestone showing how much remains to be learned about Mediterranean biodiversity.

The jellyfish discovery lands amid a wider rethink of how ecosystems admit newcomers.

According to The Economic Times, MIT physicists built more than 400 miniature ecosystems of 12 to 20 soil bacterial species and found the communities most easily invaded were the most chaotic ones with constantly fluctuating populations, while stable ecosystems resisted.

That overturns the conventional expectation that higher biodiversity always blocks invasion, and it may help explain why probiotic supplements take hold in some people's guts and not others.

For a barely known jellyfish carving out a niche off Alicante, such dynamics could shape whether it spreads or stays local.

Eight years after the initial collections, a sampling campaign with Valencia's Oceanogràfic gathered more than 200 specimens for further study, and some are now displayed in the Oceanogràfic's Medusa Lab under a magnifying glass — the first time this species has been kept in an aquarium, according to biologist Miguel Candelas.

Key questions remain: its reproductive cycle, its role in the food web and its ability to sting all require investigation, phys.org reports.

Small gelatinous organisms can prey on fish eggs and larvae, so the team's Horizon Europe Sea4Future project, spanning 22 partners from 12 countries, is studying these interactions as it works to restore Mediterranean fish stocks while protecting turtles, dolphins and whales.