The Starfish of Hong Kong, Part 5

Pentaceraster chinensis (no English common name)

Pentaceraster regulus – a relative of P. chinensis. Image by Bernard Dupont cc-by-4.0

A tropical starfish know from several locations including Hainan.

Luzon Sea Star (Echinaster luzonicus)

Echinaster luzonicus from Pulau Tioman (Malaysia)
Author Ron Yeo, cc-by-nc-sa.

The Luzon sea star is prone to shed its arms, which then regenerate into new individuals. It is normally six-armed but often quite asymmetrical in appearance, because of it has a habit of shedding arms. Its colouring ranges from red to dark brown. It is found in the tropical and sub-tropical western Indo-Pacific region, ranging from Madagascar and the east coast of Africa to Northern Australia, Indonesia and the Philippines. It is found on both reef crests and in the intertidal zone where it feeds on bacterial and algal films that it extracts from the sediment. By shedding its arms for regeneration the species can reproduce asexually. The shed arm regenerates, growing a new disc and further arms.  Up to 65 cm in diameter.

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The Starfish of Hong Kong, Part 4

Eight-armed Luidia sea star (Luidia maculata)

Luidia maculata (Seven armed starfish) taken in Ras Sedr,Egypt in 2012 by لا روسا (cc-by-sa 4.0).

The diameter with arms is 12 – 20cm and it has  5 – 9, but normally 8 arms. The arms are long, rounded and tapered to a sharp tip. The tips bear small sharp spines on the sides. The underside is pale and the grooves along the arms bear large tube feet with club-like, pointy tips. The colours and patterns on the top side are variable from greyish blue, to brown and beige, but normally have a darker star-shaped pattern in the middle, and dark irregular bars running along the arms. It ranges from SE Arabian Sea, Persian Gulf, Maldive area, Ceylon, Bay of Bengal, East Indies, north Australia, Philippine, China and south Japan. Occurs inshore at depth from 0-134 m. Observations in Hong Kong include near Kau Sai Chai in Sai Kung and near Port island. It burrows in soft sediments and eats small invertebrates including other starfish.

Astropecten monacanthus

image directly linked from the website: Echinoderms of the Gulf of Eilat (Aqaba)

Distributed in SE Arabia, Maldive area, Ceylon, Bay of Bengal, East Indies, norh Australia, Philippine, China and south Japan. Lives inshore in tropical, Indo-west Pacific Ocean waters at depths from 0 – 50 m. Observed in Hong Kong from Tai Long Sai Wan, in sand substrate.

The Starfish of Hong Kong, Part 3

Cholcolate Chip Starfish (Nidorella armata)

image by Steve Ryan, cc-by-sa 2.0.

Nidorellia armata is also known as the chocolate chip star which leads to confusion with Protoreaster nodosus which is also know as the cholcolate chip starfsih in english. It has a diameter of about 23 cm and lives on rocky surfaces with algae and seagrass at depths of 5 – 70 m. They feed on small invertebrates and algae which they digest externally by turning their stomachs inside out  and covering their prey with it. They are found in tropical waters clinging on corals and rocky reefs.

Sand Star (Archaster typicus)

image by Rie Tan cc-by-sa 2.0 .

It is found in shallow waters in the western Indian Ocean and the Indo-Pacific , incouding the Maldive Islands, the Bay of Bengal, Singapore, northern Australia, New Caledonia, the Philippines, China, southern Japan and Hawaii. It usually occurs in areas of the seabed with soft sediments such as sand, silt and seagrass meadows at depths down to 60 m. Larvae settle among mangroves and the young adult individuals gradually move to seagrass and sandy habitats as they age.  It eats detritus and anything edible it comes across by everting its stomach through its mouth and on to its food item. The food is then engulfed and brought inside the starfish where the stomach is returned to its normal position.

Chinese White Dolphin Stuck in Pearl River Tributary

Wildlife experts in south China are trying to rescue an endangered Chinese white dolphin (Sousa chinensis) that is in worsening health after swimming into a tributary of the Pearl river a week ago. The dolphin is approximately 30 years old and swam into the Baisha Rivernear Jiangmen in Guangdong Province on the 1st of February. It is now in a stretch of water about 100 km from the sea. “[…] the skin of the dolphin is festering and its health is deteriorating … its moving area is shrinking,” said Feng Kangkang, a worker with Jiangmen Chinese White Dolphin Nature Reserve, on Thursday. The team is watching the dolphin around-the-clock and recording its health condition, according to the Guangdong provincial ocean and fishery department. Dubbed the “giant pandas of the sea” by some, the Chinese white dolphins are mainly scattered in a few coastal areas where they exist in small numbers. About 2,000 are known from areas around the Pearl River, including HK which at the last count, was down to about 60 dolphins. (Photo/Xinhua)

HKU Student Identifies Dinosaur-Era Fish in Sai Kung Rocks

A Hong Kong University (HKU) student is said to have identified a Jurassic fish from Lai Chi Chong after studying some fossil collections at the university’s Stephen Hui Geological Museum.

Edison Tse Tze-kei found the specimen by chance as he was doing a research project in his final year of undergraduate study during the 2013-14 academic year, according to an announcement from HKU.

The fish, which is believed to date back to around 147 million years, represents the first dinosaur-era vertebrate specimen identified in Hong Kong, the university said in a statement posted on its website Thursday.

   

 

Tse, a graduate of the class of 2014, completed the research, description and identification under the supervision of three professors, including Michael Pittman, Research Assistant Professor and Head of the Vertebrate Palaeontology Laboratory at HKU.

The research results will now be published in PeerJ, an open access, peer-reviewed, scholarly journal of biological and medical sciences, by the end of this month.

The fossil specimen was found at Lai Chi Chong in Sai Kung, which is within the Hong Kong Geopark area, and was kept at a HKU museum.

The Jurassic fish was an osteoglossoid teleost fish, which is also referred to as Paralycoptera.

 

The preserved skeleton represents the first of such fish species from Hong Kong and the most southerly Paralycoptera identified to date, meaning that the activity area of the fish could be larger than scientists had first estimated.

Matthew Sin, a spokesperson for local NGO Green Power, said some visitors to Lai Chi Chong may have taken away rocks as souvenirs.

He reminded people that taking any sedimentary rocks, fossil, mineral or even sand samples from the Geopark is illegal.

Featured image: Magnified image (inset) of a fossil specimen from a Lai Chi Chong geological collection. Research by a HKU student has led to Hong Kong’s first identified dinosaur-era vertebrate. Credit:10.7717/peerj.865