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Hong Kong Baptist University biologists discover three new species of coral in Hong Kong waters | Taiwan News

HONG KONG SAR – Media outreach – July 7, 2022 – Biologists from Hong Kong Baptist University (HKBU) found in Hong Kong waters three new species of hard corals that have never been identified elsewhere in the world. The findings come shortly after the discovery of a new coral and two new species of nudibranchs, announced last year as part of their coral health research project in Hong Kong.

Professor Qiu Jianwen (right) and Mr. Yiu King-fung (left) introduce the new species of coral.

The new marine species have been identified by Professor Qiu Jianwen and Master’s student Mr. Yiu King-fung from HKBU’s Biology Department. The descriptions of the new corals have been accepted for publication in the academic journal Zoological studies.

New species discovered during coral health research

About eight years ago, Professor Qiu and his team started a series of research projects related to coral health in Hong Kong, including studies on the impact of bioerosion of sea urchins and coral-eating nudibranchs, as well as coral bleaching caused by global warming. A coral facility has been set up at HKBU to cultivate corals and conduct controlled experiments to examine their physiological changes under different culture conditions. Through continuous field surveys and extensive research, the team revealed the great diversity of sun corals in Hong Kong waters.

The three new species of sun corals discovered this time were named by the HKBU team as Tubastraea dendroida, Tubastraea chloromura and Tubastraea violacea, and they all belong to the genus tubastree. The samples were collected when the team investigated coral-eating nudibranchs in Sung Kong and Waglan Island in eastern Hong Kong waters. With the addition of three new members, the number of known species in the tubastree genre went from seven to ten.

The characteristics of the three new species of sun corals are as follows:

Tubastraea dendroida

Similar to most sun coralsTubastraea dendroida has a typical bright orange color, but its shape is rather unique. Instead of growing in clumps like most of its related species, this new species has a tree-like structure, with the main stem of its colony attenuated from base to tip. So the HKBU team named him “dendroidto reflect her tree-like body.

Tubastraea violacea

Covered with a thin layer of pale purple tissue over the corallites (skeletal cups), Tubastraea violacea distinguishable from other related sun coral species because its polyp wall tissues and skeleton are purple in color, and it has been named “purplishas a result. Nevertheless, its tentacles are yellow and the corallites are thick-walled. Based on comparisons with DNA sequences in public databases, the team found that this species may have color variants elsewhere, as a yellow color variant in New Caledonia in the South Pacific.

Tubastraea chloromura

This coral has a delicate olive-green skeletal wall and a ring of yellow tentacles surrounding its mouth. Accordingly, the species was named “chloromura“, with “chloro” and “murus” meaning “green” and “wall” respectively.

Using coral gene sequences recorded in public databases, HKBU biologists envision the potential distribution of Tubastraea dendroida and Tubastraea violacea in Japan and the Western Pacific Ocean. However, at this point, Tubastraea chloromura inhabits only the waters of Hong Kong.

All of these three coral species are non-reef-building corals. They do not host symbiotic algae which produce nutrients and energy via photosynthesis. Living in deeper water between 10 and 30 meters deep, they gain energy and nutrients by capturing zooplankton from seawater using their tentacles.

Discovery of new species suggests rich biodiversity

“Our discovery of three new species of tubastree improves our knowledge of the diversity of this genus of solar coral. Since corals are one of the best-studied marine animals, our study reveals how little we know about marine diversity and how many undescribed species are still awaiting our discovery,” said Professor Qiu.

The identification of the three new coral species comes less than a year after Professor Qiu and his team announced their latest discovery in October 2021. While implementing a project supported by the Environment and Conservation Fund to assess the diversity and impact of coral-eating nudibranchs, the team discovered a new species of sun coral in the genus tubastree and two new species of nudibranchs of the genus Phestille in Hong Kong waters.

Looking back, the last time a new species of hard coral was discovered and named in Hong Kong was around 20 years ago. “The discovery is very encouraging as it provides strong evidence of the high marine biodiversity in Hong Kong’s waters, and it helps fill gaps in biodiversity knowledge, as called for in the Hong Kong Strategy and Action Plan. government on biodiversity. It also inspires us to further explore the diversity of marine animals, study their ecosystem functions and services, and protect them from possible human disturbance,” added Professor Qiu.

Video:
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Pictures:
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Professor Qiu Jianwen (right) and Mr. Yiu King-fung (left) introduce the new species of coral.

Please click here for more pictures:

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Tubastraea dendroida: A colony on the ground.

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Tubastraea dendroida: Skeleton of two colonies.

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Tubastraea violacea: A colony with extended tentacles.

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Tubastraea violacea: A colony with retracted tentacles.

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Tubastraea chloromura: A colony with retracted tentacles.

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Tubastraea chloromura: (Left) Close-up of a corallite with extended tentacles. (Right) Close-up of the skeleton of a corallite.

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