Thursday, May 14, 2009

Braving the Rain at Pasir Ris 140509

Even before the trip started, KS informed us of the impending storm that was blowing over from Sumatra. We could see dark clouds gathering, but decided to start exploring anyway.

Very happy that there were quite a number of 'firsts' for me today again :) Starting them off was this peanut worm (Phylum Sipuncula). They are called peanut worms as their skin, when contracted, resembles the texture of a peanut shell. More on different kinds of worms soon. Haha.

As I walked on, I decided to take a look at one of the many tidal pools. Though there didn't seem to be anything interesting at first glance, movement soon caught my eye. A piece of shell was moving when it had no obvious reason to (there was no water current in the pool). I was pretty sure that a Leaf Porter Crab (Neodorippe callida) was the cause, and yeah, the little crustacean indeed had taken refuge under the shell.

When I flipped the shell over, the Leaf Porter Crab kept really still (playing dead, perhaps?) while lying wrong side up. After several moments, with its legs twitching into action, it righted itself and proceeded to scurry under the shell.

I remember that during the biodiversity practical we had in school, we caught a Leaf Porter Crab - a large specimen it was too! It was carrying a small rock around, a most peculiar sight.

In the same pool, there was a lone Striped Bead Anemone.

Even broken shells are useful! Making this broken shell its home was a small hermit crab.

Further up the shore, I saw many Black Sea Urchins (Temnopleurus toreumaticus). Many were tangled in the seaweed. Tried to rescue a few that were stranded..but there were just too many. Like KS says, we should let nature run its course..

The two pictures at the top show a test - its skeleton - of a Black Sea Urchin. The bottom two pictures are of a live sea urchin. As always, there is a banded worm curled around the mouth of the echinoderm. When flipped over, the beak-like structure of its mouth is visible. It is called the Aristotle's lantern after Aristotle (a famous Greek philosopher) who first described it.

More echinoderms, this time a ball sea cucumber (Phyllophorus sp.). Found it among the seaweed and brought it down into the water. Got a bit of a shock when I turned it over and saw a small crab scuttling over the sea cucumber (pic on the left).

This Mini Carpet Anemone (Stichodactyla tapetum) was the only one that I came across. Wonder if this anemone has any mutualistic relationship with shrimp or nemos. In the picture on the left, a prickly ball sponge can be seen. Both organisms may look harmless, but they should not be handled. Anemones have stinging cells and sponges have spicules which can easily get embedded in one's skin.

Just beside the carpet anemone was a large rock. In one of the recesses of the rock, water had collected. Though the surface of the water was calm, some current was being generated within. Intrigued, I squatted beside the rock for some time and caught the following sequence of pics.

It's a strange feeling when a Thunder Crab (Myomenippe hardwickii), stares at you with one red-lined green eye. It would inch slightly out of the hole, raise its left pincer out of the water and retreat quickly. At one point, it even stuck its eye out of the water. The water was rather murky, but I could see some feathery extensions from its mouth which were waving about in the water as the crab generated a current. What could these extensions be? I would have liked a clearer look, but did not want to disturb the crab (further).

These yellow egg cases are rather commonly seen on rocks along the shore. They belong to a mother Spiral Melongena (Pugilina cochlidium), a mollusc which is encountered rather frequently.

Okay, it's time for the worms! As you can see, I was rather fascinated by these worms. They were writhing about the area just behind the Spiral Melongena eggs.

At first, they appeared to be connected. Note their light blue and black colouration.

Subsequently, they moved apart. Hmm..were they mating?

Here's a close-up shot of one of them...

...and another of the worm on the right. Can't find their ID =X

When while along, I glanced at a patch of seaweed and noticed this small crab with long eye stalks. It's probably a sentinel crab (Macrophthalmus sp.).

This bivalve shell is really pretty with its different band of colurs. Wonder what mollusc it belongs to.

More molluscs! This time gastropods. These are Tiger Moon Snails (Natica tigrina) which secrete sand collars to lay their eggs. As you can see, the two moon snails on the left were engaging in some strange (maybe it is just strange to humans) behaviour. One was enveloping the other with its muscular foot.

Ah! The highlight of the day has to be the two octopuses (Family Octopodidae) which sharp-eyed ZL spotted. This small smooth headed octopus was pulling itself along the spoon seagrass. We later brought it down to the water.

It bunched itself up.

Octopuses are able to change colour and this one did! It was purplish-gray when among the seagrass and changed colour to match its new surroundings.

ZL spotted the second smooth headed octopus as well. It was noticeably bigger than the first. One of its tentacles was shorter than the rest, probably as a result of injury.

This purple sea cucumber (is it a purple under-a-stone sea cucumber?) was firmly stuck to a rock.

Back to worms. Haha. Might this be a bristleworm?

This really small snapping shrimp (note the enlarged pincer) was keeping very still when we chanced upon it.

This prickly sponge had anchored itself to the side of a rock.

At the strand line, a lot of seaweed had washed up along with these blob-like creatures. Can't say for sure what they are, but they might be ascidians. Within them, petaloid patterns were evident.

Ria found this test of a heart urchin (Order Spantangoida) just as we were about to leave. Unlike other sea urchins, heart urchins lack the Aristotle's lantern structure.

For more on today's trip, check out Ria and KS' entries at and respectively.

Note to self:
Put spare clothes in a waterproof case next time. As I'm actively cutting down on plastic bag usage, I decided to just stuff my clothes in my bag. Not the best idea coz that set got wet as well. Prolly I should reconsider changing my stance on plastic bag usage to 'use when necessary'.


  1. Fantastic finds!! I love the ribbon worm photos especially. Thanks for sharing!

  2. :) No problem! I agree with what you said in your email in that they have a similar colouration to ribbon worms but resemble the 'other worms'. Hope we can find the ID soon!

    Ribbon worms:

    Other worms:

    Thanks for sharing the links above :)

  3. Should try ziploc bags then. They last longer. :)
    Long time, no see!!!

  4. Siti!! Hahah..nowadays I only trust the ziploc bags from the army market but have since run out of them at home. Yeah! Long time no see!!! We must meet up soon!

  5. Henrietta
    Wow, you know a lot of marine lives.
    Very good blog. Thanks for sharing.

  6. Thanks! Just started learning :) Have been to your blog too..ur pics are really really wow!