When Divers Shared A Mystery
In the clear blue of the East China Sea, just off the coast of a small Okinawan island, something extraordinary emerges from the reef: a creature no larger than a fingernail, translucent, almost ghostlike, yet marked with the delicate tracery of white “bones” and a splash of black that eerily evokes a panda’s face.
It is Clavelina ossipandae, the creature now popularly known as the “skeleton panda sea squirt,” and its discovery is a gentle reminder that the ocean still holds secrets cloaked in wonder.
In 2017, local divers around Kumejima Island in Japan’s Ryukyu Archipelago began posting photos of strange transparent clusters affixed to coral and rock. At first glance, the images looked like natural curiosities—a pale ghost with dark eyes. But as more people shared the images, the oddness became irresistible.
Shunji Terai, who runs a diving shop on Kumejima, became one of the creature’s early champions. His clientele would ask: “What is that weird panda-face thing?” The photos spread via social media and even made appearances on NHK and other Japanese broadcasts.
In 2018, Naohiro Hasegawa, a specialist in tunicates at Hokkaido University, saw one of those images on Twitter and paused. He recognized that it was unlike any sea squirt he’d encountered—they did not usually look like skeletons or pandas. He mused publicly that the creature might represent something unknown.
Thus began a gentle but determined chase: the scientists would need specimens, careful analysis, and patience.
To The Reef, Under Tide And Current
In the winter months, when strong currents exposed parts of reef rarely accessible, the research team mounted an expedition to the rocky outcrop of Tonbara, off Kumejima Island. Supported by crowdfunding and local collaboration, divers collected four colonies of the creature in 2021.
Back in the lab, Hasegawa and Hiroshi Kajihara conducted both morphological and genetic analyses. In a paper published in Species Diversity on February 1, 2024, they formally described the new species as Clavelina ossipandae, giving it a home in the genus Clavelina.
They named it with intention: “Clavelina” means “little bottle,” reflecting the shape of many such ascidians, while “ossipandae” evokes os (Latin for bone) and panda, pointing to both its skeletal lines and panda-like markings. The Japanese nickname gaikotsu-panda-hoya, meaning “skeleton panda ascidian,” had already become popular online.
Anatomy Of A Mystery
What makes C. ossipandae so striking is not only its diminutive size—reaching at most about 20 mm (0.78 inches) in length—but the way it displays its internal architecture outwardly.
- Its body is largely transparent, so that internal structures are visible.
- Fine white blood vessels run horizontally across its gill area, forming a rib-like pattern reminiscent of a skeleton.
- Near its oral and atrial siphons, the creature bears four black markings—one central dot, one dorsal, and two lateral—creating a panda’s “eyes and nose” illusion.
- Morphologically, C. ossipandae differentiates itself from 44 other known Clavelina species by features such as its free zooids, number of stigmatal rows (10–14), two longitudinal muscular bands from abdomen to endostyle, and others.
On the genetic side, the researchers sequenced fragments of the cytochrome-c oxidase subunit I (COI) gene from the holotype and a paratype. They differed by 1.26 % (10 nucleotide positions), confirming they were the same species, and phylogenetic analyses placed C. ossipandae as a sister species to C. australis, found in Australian waters.
Ecologically, the species lives in colonies of 1 to 4 zooids, connected by thin strands. The entire colony anchors to reef substrate in strong current zones, typically at depths up to 20 m. It is a filter feeder, pumping water to extract plankton and organic particles—nothing particularly exotic in lifestyle, but exceptional in presentation.
Reactions, Questions, And The Wonder Of Small Things
Once the new species was announced, it drew immediate interest beyond niche scientific circles. Media outlets ran features with bewildered admiration. Some framed it as a viral oddity—“a panda skeleton floating underwater”—while others treated it as a lesson in humility and wonder.
According to the report by LiveScience, Hasegawa explained that the white lines resembling bones are actually the creature’s blood vessels. The dark spots around its head are merely natural markings, and their purpose or origin remains uncertain to researchers.
The Species Diversity paper itself carries a poetic title that asks: “Graveyards of giant pandas at the bottom of the sea?”—a playful reflection on its strange appearance.
Yet questions persist. Why these markings? Are they camouflage, mimicry, or simply a developmental oddity? What is the full range of C. ossipandae—is it confined to Kumejima, or hiding in reefs elsewhere?
In fact, beyond the type site, other specimens collected in the region are awaiting description—hinting that this panda skeleton might be only the first known representative of a broader lineage.
On forums, skepticism also appeared. Some wondered whether the images were manipulated or misinterpreted. Such doubts are perhaps natural when a creature looks surreal. Yet the detailed morphological work, live specimens, and genetic analysis give strong basis to the claim.
A Deeper Meaning In Small Discoveries
To some, a two-centimeter sea creature may seem insignificant. But in nature’s bookkeeping, every new species carries a story. In this case:
- It underscores how digital culture and citizen observation can lead to scientific breakthroughs.
- It reminds us how much remains hidden in shallow waters—and how undersampled many marine habitats remain.
- It invites humility: even in an age of satellites and deep-sea probes, nature still reveals marvels at the fingertip level—if we look, listen, and wonder.
- It projects hope: in an era of biodiversity loss, new life still finds a way to persist, adapt, and enchant.
When imagining the skeleton panda sea squirt drifting under moonlit reef currents, one sees a tiny ambassador—a whisper from an uncharted microcosm that teaches us to be curious and kind, and to guard the fragile reef home from which it calls.
End With Heart
The skeleton panda sea squirt invites more than scientific curiosity—it invites wonder. It tells us that every reef, nook, and shadow may host something entirely new, something that challenges how we see life. In a world facing so many losses, its quiet existence is a soft spark of hope: nature’s surprises are not yet exhausted.
We can carry that spark forward by listening to reefs, protecting their waters, supporting science, and nurturing humility before the small and strange. Perhaps next time you peer into a tide pool or reef, you’ll remember the little creature dressed like a panda skeleton—and understand that wonder still floats just beneath the surface.
Sources:
Reuters
Livescience
CNN
