Sunday, December 14, 2008

Fascinating eight-armed sea stars

Today while exploring a new shore, we were looking hard for sea stars. Soon, Ria called me over as she found a sea star that is not even common in the first place.

It's the eight-armed sea star (Luidia maculata) that is not commonly sighted! In fact, it is now listed as 'Endangered' on the Red List of threatened animals in Singapore. It was formerly found near the mainland prior to reclamation but recently known only from the Pulau Ubin and Pulau Tekong area in low numbers. Nevertheless, it has even been now found at the intertidal area of Semakau!

According to Lane, it burrows in soft sediments and feeds on small buried animals such as molluscs and other echinoderms.

When we first found this fascinating big sea star of about 30cm in in diameter, it was in this weird "squatting position" with their whitish pointed tube feet hanging downwards.

Taking a look at its underside, there was no prey! Why did this sea star position itself like that? Hmm, I've no idea though unfortunately.

Soon, Ria and Chay Hoon found yet another Luidia sea star!

Taking a closer look at its aboral surface, it seems that this sea star has orange pigments on top of its darker brown pigments. Something a bit different from the usual Luidia maculata we see.

What surprised all of us is that the whitish tube feet each have an orange stripe across which was never observed in any of our previous sightings.

Could this be another Luidia species for Singapore?!

Another interesting thing about this particular star found was that it has a regenerating/generating arm coming out. So it has nine arms! Amazing.

I later found another eight-armed sea star that has also the orange strip on its tube feet.

And the fourth one too, this though doesn't have the orange stripe on its tube feet.

It's fascinating to discover new stuffs from our marine sea stars! And it will be a treat if they are new Luidia records.


Lane, David J.W. and Didier Vandenspiegel. 2003. A Guide to Sea Stars and Other Echinoderms of Singapore. Singapore Science Centre. 187pp.

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