Wednesday, December 26, 2007

Discovery @ Chek Jawa on 24 Dec 2007

Fortieth Discovery posting:

It was Christmas eve spent at Chek Jawa. And i was there helping Kok Sheng with his Chek Jawa project.

Quote from his project blog:
This project aims to study the mass mortality and recruitment of macrofauna for example like carpet anemones. This project is not just for my UROPS assignment in National University of Singapore, but also for the long run monitoring and understanding of Singapore's favourite shore, Chek Jawa in Pulau Ubin.

It was a starry Christmas eve, so i'll feature more echinoderms in this posting.

If you are still wondering what am i referring to. See first 'discovery' (picture below)
Discovery Note:
1. Sea stars belong to the class Asteroidea.
2. The sea star above is probably a cake sea star , Anthenea aspera.
3. Distinguishing features for this species are the large bivalved pedicellariae (pincer-like structures) on the oral surface (under side where you find its mouth), with smaller versions found on the marginal plates and tiny scattered pedicellariae on the upper or aboral surface.
4. The upper surface of the disc is convex while the oral side is flat.
5. The arms are triangular, slightly upturned at the tips and boarded by prominent marginal plates.

Second 'discovery' was something that got Kok Sheng very excited, as although he heard that the common sea stars, Archaster typicus, have returned to Chek Jawa, this was the first time he saw them with his own eyes (picture below).
Discovery Note:
1. Their arms are flat topped with angular edges, and sides that are parallel at the base, tapering to a point distally.
2. They have a pattern of transverse, sometimes indistinct, dark bands on their arms.

Third 'discovery' were spiny sand stars, Astropecten indicus (picture below).
Discovery Note:
1. They are able to ingest their prey whole, this is distinct as most other sea stars extrude their stomach out through the mouth to digest their prey extra-orally.
2. A dark line is often visible extending along the mid-line of the upper surface of each arm.
3. They bear prominent spines that give the arms a comb-like appearance, thus the other common name of comb sea star.

Besides being a place with rich flora and fauna life, Chek Jawa also offers everyone a great nature scenery which we urban dwellers may not stop to take in its beauty, the sunset (picture below).
Although i was quite tired as i had to move all around (i was Kok Sheng's lovely assistant of the day..haha), it was a fun day. Thanks everyone and of course the wonderful weather!

Read more about the latest updates of the project here.

David J. W. Lane & Dider Vandenspiegel. A Guide to Sea Stars and other Echinoderms. Singapore Science Center, 2003.

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