The Starfish of Hong Kong, Part 6

Bordered Seastar (Craspidaster hesperus)

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Described as the new species Pseudarchaster spatuliger in 1934, it was later revised to an already known species. The diameter with arms is about 10 cm. It is a flat starfish with tapered arms. The edges of the body are bordered with large, wide plates giving it its english name. The tube feet are pointy and not tipped with suckers like other starfish. Occurs from the Bay of Bengal to China and southern Japan.

Sand-sifting Starfish (Astropecten polyacanthus)

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The sand sifting starfish or comb sea star is a widespread species, found throughout the Indo-Pacific region in shallow tropical and sub-tropical seas (from the Red Sea and Zanzibar to Hawaii, and from Japan to Australia and New Zealand). The diameter including arms is up to 20 cm. The upper surface is dark purplish in colour and the underside is orange. Little pillars with flattened top on the upper surface are cream, grey or brown, sometimes making chevron patterns. Along the edges of the arms are long, sharp spines, with brown bases and pale tips. It spends its time buried in silty seabeds feeding on detritus and small invertebrates. Sometimes it also engulfs pebbles and digests the biofilm (bacterial and algal films) and small invertebrates adhering to the surface. It contains the potent neurotoxin, tetrodotoxin, also known as TTX which has no known antidote. In a case of paralytic poisoning in Japan it was found that the victim had eaten a trumpet shell, Charonia lampas, which had acquired the toxin through its food chain, thus implicating Astropecten polyacanthus.

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hkmarinelife

I am a ex-marine biologist now working for a regular job, but I am still passionate about marine biology and oceanography. I studied Marine Science and completed a PhD in deep-sea ecology and biodiversity. I fell in love with HK's rich marine environment when I was a child. This blog is my collection of interesting facts, news and articles that celebrate and educate on HK's diverse marine environment.

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