Jun 3, 2008

Pasir Ris Bliss: more critters!

Besides stars and urchins, the Pasir Ris shore was also alive with all kinds of other animals!Under the scattered stones and rocks there were octopuses! I saw two of them, but just their arms sticking out from under a large rock. They seemed quite large and appeared to be the kind that we see on Changi, rather plain and smooth, unlike the more colourful ones we see on our Southern shores. The tide was very low so they weren't out hunting.

What was out hunting though, was this Tiger moon snail (Natica tigrina).Moon snails love to eat button snails. I looked and I looked (because Kok Sheng is interested in them) but didn't see any button snails, not even on the small sand bars nearer the low water mark.

The shores were lively with Flower crabs (Portunus pelagicus) of all sizes, and I saw this large Moon crab. The old scientific name of this crab is Matuta lunaris and now more and more people refer to it as Ashtoret lunaris. Here's some details from the stunning Systema Brachyurorum Part 1 by Peter Ng et. al (2008) in The Raffles Bulletin of Zoology, "an increasing number of workers have chosen to recognise ... Matutidae and Calappidae as two taxa as distinct families ... Until more work is done, we take the somewhat more conservative approach and keep the Matutidae and Calappidae in one superfamily, Calappoidea."

Quietly having little parties in small groups of two or three were lots of tiny little hermit crabs.These are probably the Tidal hermit crab (Diogenes sp.). There were not that many Striped hermit crabs (Clibanarius sp.) unlike at Changi.

Another cuddly couple was this goby and snapping shrimp!Some gobies live together with a snapping shrimp in its burrow. The more keen-eyed goby keeps a look out for danger and annoyances (such as shore explorers). Meanwhile the short-sighted snapping shrimp does the house-keeping on the burrow like a little bulldozer. It was dark and I guess they don't equate a weak torchlight with danger. But after this flash photo, they both disappeared into the burrow in a flurry of sediments.

The pools were thick with tiny little gobies. There were the usual Brown shore gobies (Drombus triangularis) and Shadow gobies (Acentrogobious nebulosus). But here is a pretty goby with little red spots whose name I don't know. Lacking a name doesn't stop us from admiring it.

Worms might seem icky to many, but I find marine worms quite fascinating.These fluffy worms with a double fan in trendy pink and black belong to the Phylum Phoronida. The phylum has less than 20 species! That's a really small phylum. Consider that fishes, birds, gorillas, us all belong to one Phylum Chordata. These Phoronid worms are often found with Peacock anemones (Order Ceriantharia) and indeed, this bunch was found near the bottom of a Peacock anemone that had retracted into its tube.

While bending over to take photos of sand stars, I noticed this colourful tube worm making a quick foray outside its tube.Isn't it pretty?! With iridescent body and feathery gills. OK, we got to ignore the scary tentacles on the head.

And here's a bunch of stuff sticking out of the sediments. I see this all the time and still haven't got a clue what they are.Probably the tentacles of some sort of worm. I also saw a short and small ribbon worm (Phylum Nemertea) with stripes, and of course, lots of bristleworms.

But the shore was truly teeming with tiny little sea anemones of all kinds.Thanks to having to keep bending down to measure the sand stars, I got a good look at them, even these very tiny ones!And there were two of these beautiful large sea anemones that I've not seen before. They had a inner ring of intriguing lobed structures.
I've seen something similar, but these were transparent with white markings and seen near mangroves at Kranji and at Sungei Buloh. We must bring Dr Daphne to Pasir Ris when she's next in town!

The short stretch of Pasir Ris that I went to today was mostly soft and silty with scattered rocks and stones. There wasn't much on the stones aside from a sprinkling of sponges and some seaweeds. Although there were a few tiny patches of hard corals!
This is Zebra coral (Oulastrea crispata) that is often seen on our Northern shores, but in tiny colonies.

There were also few small patches of Spoon seagrass (Halophila ovalis) with big green leaves, like the kind we see at Changi.There's much more of the shores to explore on Pasir Ris, and we must certainly find some opportunities to do so.

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