Sunday, December 6, 2009

1st time encounter with this Star on Semakau

107th Discovery Posting

Probably one reason that I continue to enjoy going for inter-tidal walks is the joy of discovering something which I have never seen before. And this happened recently on Friday night when we (a few Project Semakau volunteers and myself) went for an exploration walk at Semakau after we did some bird and insect surveys.

In the beginning, I thought that this was a biscuit or cake sea star (photos below).
But after R pointed out that this could be a galloping sand star (Stellaster equestris), I decided to give it a double check. To my joy, R was correct. According to David's Lane, A Guide to Sea Stars and Other Echinoderms to Singapore, the galloping sand star has "variable amounts of dark-pigmented patterning on the oral surface." This was observed on the oral side of the sea star we've seen (photo above). So this is a 'first' for me! Rightfully, the first 'discovery' of this posting.

Not only did we manage to see one of them, but two! Here's the second one (photo below).
I almost forgot to mention that this could be the first time anyone in Singapore has seen it in the inter-tidal area as previous specimens has been only found through dredging. Thanks to R for pointing this out! Oh, by the way, unlike most other sea stars which move by gliding across the substrate, this sea star is able to move by jerking or leaping.

During our walk, we also managed to spot the usual big sea star suspects, the knobbly sea stars. Here's two of them and the second 'discovery' (photos below).Initially, I thought the third 'discovery' was a gong-gong. But R pointed out this was a Strombus marginatus, thanks again! (photo below)I did a quick search and found a recent paper on this shell, here's the link (you can check out the pictures if you're not interested in reading it): http://rmbr.nus.edu.sg/nis/bulletin2009/2009nis379-384.pdf.

It was quite a fruitful night as we across came across a number of squids, here are some photos of them below.It has been said that squids are probably the fastest moving aquatic invertebrates with some reaching up to 40km/h but the ones we saw were quite still. Maybe it was because it was night time or rest time?

Some people like me tend to mix up squids and cuttlefishes, so one good way to tell them apart is to look out for fin. An all round fin is a cuttlefish while the squid's fin is a triangular flap at the tip of the body which acts as stabilisers.

To read more about them, you can go to http://www.wildsingapore.com/wildfacts/mollusca/cephalopoda/squid.htm.

Well, it was a great night out and we were out again on the shores on the night after (sat). You can read about them @
a) http://tidechaser.blogspot.com/2009/12/last-project-semakau-survey-of-year.html
b) http://mantamola.blogspot.com/2009/12/night-trip-to-semakau.html

1 comment:

koksheng said...

Great Star find!!!! :-)