Marine researchers have identified a vibrant new species of deep-sea precious coral off the coast of Kochi Prefecture, Japan. The new species, named Hemicorallium osmanthogemmum, was described by Tatsuki Koido from the Kuroshio Biological Research Foundation and published in the open-access journal ZooKeys.
The specimen was originally brought to the surface after being incidentally hooked at a depth of approximately 550 metres off Cape Ashizuri during longline fishing operations for alfonsino fish. Recognising its unique characteristics, the collector deposited the specimens at the Kuroshio Biological Research Foundation for further study.
Through microscopic examination of the coral’s tiny skeletal structures (called sclerites) combined with advanced multi-gene DNA analysis, the coral was confirmed to be entirely new to science, marking the first time the deep-sea genus Hemicorallium has ever been reported off Kochi Prefecture.
Resembling Sweet Olive Buds: The Etymology
The scientific name of the new species, Hemicorallium osmanthogemmum, has a beautiful meaning rooted in botany. The specific name is derived from Osmanthus (the plant genus containing the sweet olive tree) and the Latin word gemma, meaning “bud”. This name highlights a distinct physical trait of the coral: its large polyp mounds are tightly clustered together at the very tips of its branches, mirroring the appearance of flower buds on a sweet olive tree.
Reflecting this resemblance, the coral has been given the new Japanese common name Kinmokusei-mizo-sango, which translates to “sweet olive groove-coral”. In life, the coral features a striking contrast of colours; its outer living tissue is a vibrant orange, while its solid internal skeletal axis is a stunning shade of pink.
The Cultural and Environmental Value of Precious Corals
Precious corals, which primarily belong to the family Coralliidae, have been highly valued by humans for centuries. Because they possess solid inner skeletons and vivid natural colouration, they are traditionally sought after globally for crafting fine jewellery and ornaments.
In recent years, however, the global perspective has shifted significantly. Instead of viewing precious corals solely through the lens of resource consumption, modern marine science is focused heavily on developing innovative methods for propagation and active population replenishment.
Japan has a particularly deep history in this field; domestic scientific study of precious corals began in the early 20th century, and discussions regarding resource conservation through coral release programmes date back more than one hundred years, showing a long-standing cultural and scientific dedication to the sustainable management of the precious coral industry.
Why This Discovery Matters
Corals in the genus Hemicorallium live in particularly deep waters where environmental sampling is extremely challenging, therefore opportunities to study them are rare. Marine biologists believe that many more undiscovered species are still hidden across these deep seafloors.
Original Study:
Koido T (2026) A new species of Hemicorallium (Anthozoa, Octocorallia, Coralliidae), along with a revised identification key to species of the genus. ZooKeys 1277: 339-354. https://doi.org/10.3897/zookeys.1277.184620
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