04 January 2010

Sun, moon and stars on Little Sisters Island

How fabulous to find the Sundial snail at Little Sisters Island!
Chay Hoon found it and another one laying an egg mass. Janette also found one! This sure puts us all in a sunny mood!

Here's what the snail's underside looks like. Like other snails, it has a 'door' or operculum to shut the shell opening.
The Clear sundial snail (Architectonica perspectiva) is listed as 'Endangered' as the original shores where they were found have been lost to reclamation. So it's really heartening to see several of them. We have recently also seen these snails at Pulau Hantu and St. John's Island.

Although Little Sisters is very small, the reefs there are quite interesting. There is one spot which has lots of feather stars (Class Crinoidea). They can be hard to spot if their many feathery arms are curled up. Can you spot the feather star in this photo?
Here's what it looks like with its arms unfurled.
Kok Sheng and James spent a lot of time and effort to look for little animals living in the feather stars. They found various worms which look exactly like parts of the feather star!

In this tiny little pool were other little creatures such as this pretty Blue dragon nudibranch (Pteraeolidia ianthina). My first time seeing it at Sisters Island.
Another pretty creature was this black flatworm with an orange and white edge (Pseudobiceros uniarborensis). The others, who spent more time here, found another flatworm with a white and orange edge! As well as lots of other interesting animals.
The reefs were thick with seaweeds. The brown Sargassum seaweed (Sargassum sp.) hides all manner of creatures. Even large animals like this filefish (Family Monacanthidae) are hard to spot.
Others are very tiny like this strange creature happily wandering through the Hairy green seaweed (Bryopsis sp.).
Occassionaly, a large animal might emerge from the forest of seaweeds. Like this Reef octopus that kept changing its colours and textures to match its surroundings.
Other animals are well hidden in holes and crevices. Such as the Coral ghost shrimp (Glypturus sp.) that excavates a smooth large burrow. All I usually see of this shy creature is a large orange pincer, and perhaps an antennae, sticking out of the burrow.
The shallow pools left behind at low tide were teeming with Tropical silversides (Atherinomorus duodecimalis) as well as lots of Chequered cardinalfish (Apogon margaritophorus). I saw several False scorpionfishes (Centrogenys vaigiensis), many Common frill-fin gobies (Bathygobius fuscus) and one Head-stripe goby (Amblygobious stethophthalmus).

And James found a Spotted-tail frogfish (Lophiocharon trisignatus)!

I also spent some time on the high shore trying to find the strange anemone that we last saw at Pulau Hantu. There were some really large and happy Peachia anemones (Peachia sp.).
And this anemone with a stripey body column.
When I coaxed it to show its oral disk, it sure looks like the Frilly anemone (Phymanthus sp.) that I often see in sandy areas. Hmm.
I didn't find the Hantu anemone, but did find lots of interesting snails (besides the Sundial snail).

Like these odd snails that I've been seeing recently at Tanah Merah as well. A kind reader of my flickr photo has identified these as Otopleura auriscati. There were a few of these snails quietly grazing on the silty sandy surface.
This pair of pink moon snails were up to something. Probably making new moon snails. This is my first encounter with them on Sisters Island.
A more commonly seen moon snail on Big and Little Sister Islands are these white ones. They are not pure white, and every time I see them, I feel more and more that they are not Oval moon snails (Polinices mammatus). I'm not sure yet what they are.
I also saw one of these special conch snails. Chee Kong, Mei Lin and Kok Sheng recently identified this snail in a paper in Nature in Singapore. It is Strombus (Dolomena) marginatus sowerbyorum. And I should make time to do a fact sheet for these pretty snails.
Like other conch snails, this snail has a knife-like operculum attached to a muscular foot which it uses like a pole-vault to hop along the surface.

Another 'hopper' that was seen in numbers was the Black-lipped conch (Strombus urceus) which is listed as 'Vulnerable'. So it was nice to see a few of these snails on the shore.
Brandon also saw a spider conch (Lambis lambis)!

In fact, over the last few days, we seem to have been seeing some very special snails. Kok Sheng found a snail on Sentosa that had not been seen since the 1970s. While Liana found a living Fig snail (Family Ficidae) at East Coast. So our shores are very much alive!

Of course the main purpose of the trip was to find Giant clams for Mei Lin's project. But aside from the one very nice large Fluted giant clam (Tridacna squamosa), we didn't manage to find any others.

To top off the end of a special evening, Brandon found these Common sea stars (Archaster typicus). There weren't many of the stars, but some were nearly as large as my foot! While others were smaller.
So on this trip, we had the sun and the moon and the stars!

We were all spread out on various parts of the shore. So as a group, we saw a wide variety of marine life. Visit their blogs to find out more!

Other posts about this trip

1 comment:

  1. I found an empty shell of a Architectonica perspective in a woodland in the heart of Somerset in England! How on earth could it have got there. I'm guessing most obvious to have been dropped by a bird but it's quite big and heavy must have been some bird! Any ideas?



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