Singapore’s waters have once again revealed the mysteries of tropical marine life. Researchers have identified a new species of venomous box jellyfish that was previously unknown to science. The species has been named Chironex blakangmati, referencing the former name of Sentosa Island: “Pulau Blakang Mati.”
The discovery was published in the scientific journal Raffles Bulletin of Zoology in May 15, 2026 by a research team from the National University of Singapore and Tohoku University in Japan. In addition to identifying a new species, the study also revealed that Singapore is a newly recorded habitat for another deadly box jellyfish species, Chironex indrasaksajiae, which was previously known only from Thailand.
A Transparent Predator That Is Hard to See
Box jellyfish are considered among the most dangerous marine animals in the world. Several species within the genus Chironex are capable of causing severe pain, cardiac complications, and even death within a short time due to their highly potent venom.
However, these animals are also notoriously difficult to study because their bodies are almost completely transparent when in water.
“Finding highly venomous box jellyfish that are nearly invisible in the water is not an easy task,” the researchers wrote in their official statement.
The new species was discovered around Sentosa Island and the Singapore Strait. Initially, researchers assumed the jellyfish belonged to Chironex yamaguchii, a species previously known from Japan and the Philippines. However, detailed morphological and DNA analysis revealed that it was in fact a distinct species.
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A Name Drawn From Sentosa’s Dark History
The name blakangmati is derived from the former name of Sentosa Island, “Pulau Blakang Mati.” In Singapore’s history, the name has often been translated as “the island of death behind.” The researchers chose this name to mark the location where the new species was discovered.
With this discovery, Chironex blakangmati becomes the fourth officially recognized species in the genus Chironex. Previously, only three main species were known: Chironex fleckeri from Australia, Chironex yamaguchii from Japan and the Philippines, and Chironex indrasaksajiae from Thailand.
At first glance, the new species closely resembles its relatives. Because of this similarity, researchers had to conduct detailed examinations of body structures and genetic analyses to confirm its identity.
C. blakangmati has seven tentacles on each pedalium, volcano-shaped canal structures, and a sharper velarial canal tip compared to other species. Most notably, it lacks a specific canal structure in a part of the body known as the perradial lappets.
Jellyfish expert Cheryl Lewis Ames said she initially believed the specimen was simply a variation of C. yamaguchii.
“I even had to reopen older collections of Chironex yamaguchii from Okinawa to compare them,” she said.
It was these small differences in canal structure that ultimately provided the key evidence that the species had never been formally described before.
Traces of Venomous Jellyfish in Singapore
The study also revealed that Singapore has a longer history of box jellyfish appearances than previously thought.
Historical records document a fatal sting incident involving a “sea wasp” in 1974. After decades of almost no reports, sightings of box jellyfish began increasing again after 2017 in several coastal areas such as Sentosa, Changi, and East Coast Park.
Some beaches were even temporarily closed following reports of venomous jellyfish near recreational areas.
Researchers suggest that increased coastal recreational activity, changes in marine environments, and climate-related factors may be contributing to the rising number of sightings.
Southeast Asia Still Holds Many Marine Mysteries
The discovery of Chironex blakangmati highlights how marine biodiversity in Southeast Asia remains far from fully documented. Even in highly urbanized regions like Singapore, new species can still be found in coastal waters heavily used by humans.
Phylogenetic analysis in the study shows that C. blakangmati forms a distinct evolutionary branch, despite being closely related to C. yamaguchii.
Meanwhile, the presence of C. indrasaksajiae in Singapore extends the known range of the species from Thailand into the Singapore Strait. This suggests that the distribution of box jellyfish in Southeast Asia may be much wider than previously believed.
For science, this discovery is more than just the addition of a new species name. Research on box jellyfish is also crucial for human safety, particularly in tropical regions with high levels of marine tourism.
Behind their nearly invisible bodies lies one of the most lethal marine venoms in the world. (Wage Erlangga)
