In the summer of 2023, a remotely operated vehicle named Deep Discoverer was crawling along the Pacific seafloor off Alaska when its cameras landed on something nobody could explain: a smooth, golden dome, roughly four inches across, sitting alone on the sediment at a depth of about 3,300 meters. The ROV’s mechanical arm extended a suction sampler and pulled the object into a collection container while scientists aboard the NOAA ship Okeanos Explorer watched the live feed and traded theories. Was it a sponge? An egg case? A coral fragment? Something entirely new?
Nearly three years later, in a preprint posted to bioRxiv in April 2026, researchers revealed the answer. The golden orb was a detached piece of one of the deep ocean’s most elusive creatures: a giant anemone called Relicanthus daphneae. Not an egg. Not a sponge. Not an alien artifact. A chunk of an animal so rarely encountered that most marine biologists have never seen one intact.
A golden puzzle from two miles down
The specimen was collected on Aug. 30, 2023, during NOAA’s Seascape Alaska 5 expedition. At the time, the team described it as a smooth gold dome about 10 centimeters wide, with a small hole or tear on one side. Its texture was unlike anything the crew had handled before. No one aboard could confidently identify it, so it was cataloged simply as an unknown biological sample and shipped to the NOAA Fisheries’ National Systematics Laboratory, housed at the Smithsonian National Museum of Natural History in Washington, D.C.
There, researchers sliced the tissue into thin sections and examined them under a microscope. What they found narrowed the field immediately: cnidocytes, the specialized stinging cells that jellyfish, corals, and anemones use to capture prey. That ruled out sponges, mineral formations, and microbial mats. The orb was a cnidarian, but which one?
DNA pointed to one of the ocean’s rarest anemones
Microscopy alone could not pin down the species. The tissue was damaged and detached from whatever animal it once belonged to, stripping away many of the structural features taxonomists normally rely on. So the team turned to genomic sequencing, extracting DNA from the preserved tissue and comparing it against known sequences in GenBank, the public genetic database maintained by the National Institutes of Health.
The match came back to Relicanthus daphneae, a giant deep-sea anemone classified within the subclass Hexacorallia. Multiple independent gene regions converged on the same result, a strong signal in molecular taxonomy. The golden dome, the researchers concluded, was part of the anemone’s base structure, the anchoring tissue that once held the animal to the seafloor.
NOAA Ocean Exploration confirmed the finding on its multimedia page, describing the specimen as part of the base of a giant deep-sea anemone. The Smithsonian’s ocean portal published a parallel account walking through the DNA analysis and its conclusion.
An animal most scientists have never seen alive
Relicanthus daphneae is not a household name, even among marine biologists. The species was first described from polymetallic nodule fields in the abyssal Pacific, environments so remote that only a handful of expeditions have ever surveyed them. Living specimens can grow remarkably large for anemones, with some individuals stretching well beyond a meter across when their tentacles are extended. They anchor themselves to hard substrates on the seafloor, and their body plan is unusual enough that taxonomists have struggled to place them precisely on the anemone family tree.
A peer-reviewed study published in Scientific Reports established that Relicanthus has a sister relationship with the order Actiniaria based on mitogenomic analysis, but the genus is still classified as “incerti ordinis,” meaning its exact order-level placement remains debated. That taxonomic ambiguity helps explain why identifying a torn-off fragment was so difficult. There was no simple visual reference to compare it against. The identification required both microscopy and sequencing working in tandem.
What scientists still cannot explain
The species-level match appears solid, supported by two independent methods. But several questions remain open, and the researchers have been careful not to overstate their conclusions.
First, the bioRxiv paper has not yet passed formal peer review. The methods and findings still await independent scrutiny from other taxonomists and molecular biologists. Raw genomic reads and complete morphological datasets have not appeared in public repositories. Existing GenBank records for Relicanthus daphneae, such as a partial COI gene sequence filed under accession MN055612.1, were generated from different specimens collected years earlier. Whether the new sequences will be deposited alongside those records is not yet known.
Second, no one can say with certainty how the orb ended up alone on the seafloor. Was it a naturally shed base? A fragment ripped away by deep-ocean currents or a predator? A stage in the animal’s life cycle that has never been documented? The orb’s smooth surface and single opening could fit several scenarios, from a degraded attachment disc to a partially collapsed body wall. Without observing a living Relicanthus daphneae in the act of shedding or losing its base, the functional interpretation remains an educated guess.
Third, with only a single specimen in hand, scientists cannot say whether golden orbs like this one are rare accidents or routine byproducts of the anemone’s biology. It is possible that similar fragments have been collected on past expeditions and misidentified, perhaps labeled as sponge tissue or invertebrate debris and tucked away unexamined in museum drawers. Until more material surfaces, that possibility stays speculative.
Why a scrap of anemone matters
At roughly two miles below the surface, the Pacific seafloor remains one of the least-observed environments on Earth. Less than a quarter of the global ocean floor has been mapped at high resolution, and the fraction that has been directly observed by cameras or human eyes is far smaller. Every specimen pulled from those depths carries outsized scientific weight because there are so few data points to work with.
The golden orb’s identification adds a new piece to the puzzle of where Relicanthus daphneae actually lives. The species was previously known from abyssal plains thousands of miles to the south. Finding a fragment off Alaska suggests the animal’s range may be broader than earlier records indicated. If future ROV dives in similar habitats recover comparable structures, researchers could begin testing whether these bases detach under specific conditions, such as shifts in deep-ocean temperature or current patterns, or whether discarded bases serve as shelter for other organisms, adding another layer to deep-sea ecosystem dynamics.
The NOAA Ocean Exploration Advisory Board has emphasized the value of repeated deep-sea transects for exactly this reason: single specimens raise questions that only additional sampling can answer. Long-term imaging of known anemone habitats, combined with targeted collection of similar domes, could eventually reveal whether detachment is part of normal growth, reproduction, or stress response.
A single object, years of patience
The golden orb story follows a pattern familiar in deep-sea science. A single, puzzling object sparks global curiosity, then gradually yields its secrets through months of careful lab work and cautious interpretation. The identification as part of a giant anemone is a strong step forward, built on converging lines of evidence. But it is not the final word. As of June 2026, the preprint awaits peer review, the raw data await public release, and the deeper questions about Relicanthus daphneae‘s biology await more dives to the same dark, cold seafloor where the orb was found.
For now, the golden dome sits in a collection at the Smithsonian, a four-inch fragment of an animal that can stretch wider than a dining table, pulled from a world most humans will never see. It spent years as a mystery. It may spend many more as a starting point.
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*This article was researched with the help of AI, with human editors creating the final content.
