11 November 2008

Wildfacts updates: Singapore's rarer echinoderms

Time to update with some special echinoderms!
Sea star (Craspidaster hesperus)
There was so much to do for the wildfact sheets that I initially focused on the more commonly encountered marine life. Now that these are uploaded, I decided to catch up with some of our more rarely seen animals.

As always, in all things echinoderm, I rely on Dr Lane's wonderful guidebook: Lane, David J.W. and Didier Vandenspiegel. 2003. A Guide to Sea Stars and Other Echinoderms of Singapore.

I finally got to making a page for the amazing Pentaceraster mammilatus, a new record for Singapore found on Cyrene Reef.

I couldn't think of a PG rated common name for the star and lamely settled on "Pentaceraster sea star". From its species name, of course the more logical common name would be something like "Nipply sea star" as suggested by Yuchen. Sigh. But we really can't use such a name on a website that is likely to be accessed by school children, can we?

In doing up the page, I also came across a poignant personal account of the discovery on the creatures big and small blog.

From Dr Lane's book, this is Laganum depressum (again I just gave up just called it Laganum sand dollar, alternative suggestions welcomed). Although its species name probably refers to the fact that it's thick in the centre and the edges but thinner elsewhere, I did encounter it under depressing circumstances. Several were seen on the Sentosa shore that is now already reclaimed for the Sentosa Integrated Resort. This sand dollar is listed among the threatened animals of Singapore.

This bright pink sand dollar was spotted by Dr Chua Ee Kiam of Simply Green and author of many nature books on Singapore. We were on one of our rare trips to Pulau Sekudu when he spotted two of them. From Dr Lane's book, it is probably Peronella lesueuri and I just went ahead and called it the Pink sand dollar. Hah!

This is why I feel it is important to regularly visit all our shores with scientists or experienced field workers. So that we can keep tabs on our common marine life and also discover some of special animals too.

Another special encounter was with Craspidaster hesperus on Beting Bronok, a Northern submerged reef. Sam of the ramblings of a peculiar nature blog found it just as we were about to leave.

It was much easier finding the common name for this star as my trusty Latin dictionary (one of the strange things acquired in the attempt to learn more biology) says 'Craspedo' means border or edge. "Bordered sea star" is still rather clunky though. Any better suggestions?

These rare stars were uploaded earlier.

One of the first corrections came from Kok Sheng of wonderful creations blog, who pointed out that I listed the Luidia species wrongly. Thank you Kok Sheng!

I've kind of left this star as Luidia sp. as I can't figure out which one it might be. Kok Sheng, others and I found these on our Northern shore and they had five arms. But the five-armed Luidia was previously only seen in the South, while those in the North had six arms.

From Dr Lane's book:

Luidia penangensis (6-armed sand star) recorded from the Changi-Ubin-Tekong area with usually six arms which are slightly constricted at the base. It is uniformly grey.

Luidia hardwicki (5-armed sand star) recorded from Sultan Shoal and the Pulau Ayer Chawan islands that have since been reclaimed to form Jurong Island. It has five arms and bivalve pedicellariae which require a strong hand lens to see.

Another strange and rarely seen star is the Cryptic sea star (Crypasterina sp.) . This star is truly hard to spot. I've seen this, so far, only on Pulau Semakau. Its arms are so short that it appears almost pentagonal. It's found under stones and clamps tight to the surface, so that the body is sometimes in a hump in the centre. It looks more like a limpet than a sea star.

I'd be very glad to hear your suggestions, corrections and will gladly upload your photos and sightings to the wildfacts page. Just email me: hello@wildsingapore.com.


It was also most heartening to receive an email from Dr Jean Yong about the wildfacts sheets. And he so generously offered to share his incomparable "Comparative Guide to Mangroves". He said "If you like, you may put the mangrove guidesheet there. All copyright belongs to me and I'm happy to share."

Alas, it will be a while yet before I can get around to do doing the mangroves. So rather low res versions of John's fabulous guide sheets will have to do for the moment.

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