What Is the Elven Abyss Tunicate and Why Is It Related to You?

The Short Answer

The Elven abyss tunicate is a newly described deep-sea species formally named in 2026, collected from depths of 2,000 to 4,000 metres off north-western Australia — and despite looking like a lump of jelly, it belongs to the same animal phylum as every vertebrate on Earth, making it one of your closest invertebrate relatives.

What Exactly Is a Tunicate?

Tunicates, also called sea squirts, are filter-feeding animals that anchor themselves to the seafloor and draw water through their bodies to extract food particles. They have no eyes, no limbs, and no visible spine. To most observers, they look more like a sponge or a piece of marine debris than anything resembling a fish or a human.

Yet tunicates belong to the phylum Chordata — the same classification that includes fish, reptiles, birds, and mammals. This is not a loose grouping. Chordata is defined by a set of shared biological features, and tunicates qualify in a deeply surprising way.

The Notochord That Disappears

Here is where tunicates become genuinely strange. As larvae, tunicates possess a notochord — a flexible rod-like structure that is the defining feature of all chordates, and the evolutionary precursor to the vertebral column. A tunicate larva, in other words, carries the proto-spine that would become a backbone in a vertebrate animal.

But when the larva metamorphoses into its adult form, it absorbs and destroys its own notochord. The adult tunicate erases every visible trace of its chordate identity. It settles onto a surface, anchors itself permanently, and spends the rest of its life as a sessile filter feeder — the biological equivalent of unbecoming what you were born as.

A Creature That Makes Cellulose

Tunicates carry one more biological oddity that sets them apart from virtually every other animal on Earth: they produce cellulose in their body wall. Cellulose is the structural material found in plant cell walls. Among animals, the ability to synthesise it is extraordinarily rare, and tunicates are the most prominent example. Scientists believe this capacity was acquired through ancient horizontal gene transfer — essentially, a gene from a bacterial or plant-like ancestor was incorporated into the tunicate genome long ago.

How Deep Was the Elven Abyss Tunicate Found?

The Elven abyss tunicate was collected from the abyssal zone off north-western Australia, at depths ranging from 2,000 to 4,000 metres. That is deeper than most research submarines are rated to operate comfortably, and far beyond the reach of natural light. At these depths, pressure is crushing, temperatures hover just above freezing, and the seafloor environment is poorly understood even by modern science.

The species was formally described in 2026 as part of ongoing efforts to document deep-sea biodiversity in Australian waters — a region that continues to yield remarkable discoveries.

How Many Species Are Still Unknown?

Approximately 240,000 marine species have been formally described by science. Estimates for the true total range as high as one million. That means the majority of ocean life — potentially more than half — has never been named, catalogued, or studied. The deep ocean, which makes up the largest habitable volume on Earth, remains one of the least explored environments on the planet. Discoveries like the Elven abyss tunicate are reminders that the abyss is not empty — it is simply waiting.