First Wild Record of Vallicula Multiformis Rankin, 1956 (Ctenophora, Platyctenida) in South-East Asia From the Andaman and Nicobar Islands, India

The ocean floor is often imagined as a place of stillness, where creatures cling to rocks or drift slowly among the weeds. Among the most unusual residents of this world are comb jellies, a group of gelatinous animals that move by beating rows of tiny, hair-like cilia. While many of these animals swim freely in the open water, a specific subgroup known as the Platyctenida has chosen a different life. These are bottom-dwellers, flattened against the seabed and often camouflaged to look like flatworms or pieces of algae. For scientists, tracking these creatures is difficult because they rarely leave their hiding spots, making it hard to know exactly where they live or how far they can travel. Understanding their range is important because it reveals how marine life spreads across the globe, whether by natural currents or by human activity, and helps map the hidden connections between distant oceans.

In the waters surrounding the Andaman and Nicobar Islands, a team of researchers from the Zoological Survey of India made a discovery that challenges the assumption that these bottom-dwellers stay put. They found a single specimen of a comb jelly called Vallicula multiformis floating at the surface of the sea near Great Nicobar Island. This was not a typical sighting; the animal was not clinging to the ocean floor but was drifting loosely attached to a floating fragment of green algae. The researchers documented this as the first time this specific species has ever been recorded in Southeast Asia and only the second time it has been found in Indian waters. The discovery is significant because it extends the known range of the species by roughly 2,500 kilometers from its previous location in the Gulf of Kutch, pushing its known territory far into the Andaman Sea.

The animal itself is small, measuring between 8 and 10 millimeters wide, with a body that is flattened and oval-shaped. It has a pale green color with tiny white spots, allowing it to blend in with the algae it lives on. Under a microscope, the researchers could see its defining features: a pair of sheaths on its sides that hold long, retractable tentacles, and a network of internal tubes that end blindly rather than forming a complete circle. These details confirmed its identity as Vallicula multiformis, a species originally described from Jamaica and later found in places like Brazil, California, and Hawaii. In this new sighting, the creature was found alongside a shell-less sea slug, a type of animal that also feeds on the same kind of green algae. This pairing of the comb jelly and the sea slug on the same floating plant fragment had been seen before in the Gulf of Kutch, but this was the first time such a co-occurrence was recorded with this specific type of sea slug in the Andaman Sea.

What makes this finding particularly interesting is the behavior of the animal. Historically, scientists have described this species as a sedentary creature that stays fixed to the bottom, rarely moving. When researchers in the past have kept them in containers, they have sometimes seen the animals detach and float, but that behavior was never observed in the wild until now. The specimen found in November was floating at the water's surface during the day, loosely attached to a piece of drifting algae. This suggests that while these animals usually live on the sea floor, they are capable of floating and creeping in the open water, at least for short periods. This ability to float could be a hidden method of travel, allowing them to hitch a ride on surface currents to reach new areas.

The location of this discovery adds another layer to the story. Great Nicobar Island sits along one of the busiest shipping routes in the world, a corridor where massive vessels travel between the Malacca Strait and the Andaman Sea. The researchers considered two possibilities for how the animal arrived there. It could have drifted naturally with the ocean currents, or it could have been introduced by human ships, perhaps hidden in ballast water or attached to the hull. The paper does not definitively prove which of these happened, but the presence of the species in such a strategic location raises the question of whether human activity is helping these creatures spread. The water where the animal was found was warm, at 31.0 degrees Celsius, and slightly salty, conditions that the species seems able to tolerate.

This single observation opens a new chapter in understanding the life of these bottom-dwelling comb jellies. It proves that they can survive and move in the open ocean, a behavior that was previously only guessed at in laboratory settings. The researchers emphasize that to fully understand the story, scientists need to compare the DNA of this new population with those from other parts of the world to see if they are truly the same species or if they represent a hidden group of related animals. Until then, the floating comb jelly off the coast of Great Nicobar stands as a quiet but powerful reminder that the boundaries of marine life are more fluid than we thought, and that even the most grounded creatures can sometimes take to the waves.