04 March 2012

Wild facts updates: Special critters, and sponges and soft corals

I didn't realise this snail is considered rare! Thanks to ID help from readers, I learnt that this is a Wentletrap, a Dutch word which means 'spiral staircase'. The elegant shell does indeed resemble one! Some species are believed to eat sea anemones, which is perhaps why I saw it on the sandy Seletar shore that had lots of anemones!
I also sorted out some sponges and soft corals, finally getting some fact sheets up for them.

With the launch of new FREE guided walks at Pasir Ris mangroves with the Naked Hermit Crabs, I thought it was high time I did a fact sheet for the commonly seen Green chromide. Thanks to Ivan for the ID, this fish is NOT native to Singapore. Naturally found in India and Sri Lanka, it was introduced to Singapore, possibly through the aquarium trade.
The enormous Atlas moth is regularly seen in many of our mangroves including Pasir Ris. It is among the insects with the largest wing area and is 'furry' all over. So it reminds me of a magic flying carpet!
I've finally gotten around to doing fact sheets for these intriguing sponges, some commonly seen on our shores! 'Hairy olives' sponge , Black bath sponge, Black antler sponge, Smooth rainbow sponge, Black prickly sponge, Thorny stem sponge, Smooth green sponge, Encrusting prickly blue sponge, Yellow bumpy sponges as well as the Beige sheet ascidians
Looking more closely at sponges, I've finally tried hard to figure out the teeny little bits that we often see on various kinds of sponges. I think they are Spionid worms (Family Spionidae). They create tiny tubes to live in and have a pair of feeding tentacles.
Unidentified worms on a sponge
Some other creatures live INSIDE sponges, like the Sponge finger oyster (Vulsella sp.). They are well embedded in a living sponge and often the only sign of one is a suspicious looking slit in the sponge which snaps shut when you get too close!
Sponge oyster (Vulsella sp.) in Yellow prickly branching sponge (Pseudoceratina purpurea)
I also squinted hard, read carefully, strained my brains to finally sort out some of our soft corals. It these larger fluffy feathery soft corals: Broad feathery soft coral and Brown feathery soft coral are probably from the Family Xeniidae.
While the smaller one with skinnier tentacles: Fine feathery soft coral are from Family Briareidae.
It was even harder on my brain to figure out the Leathery soft corals (Family Alcyoniidae) that we often see. The characteristics to look out for are the structure of autozooids, polyps on long stalks with eight tiny branched tentacles that emerge from the shared leathery tissue. And the presence of siphonozooids which don't emerge from the shared tissue and function as water pumps for the colony. They appear as tiny holes or bumps in between the taller autozooids. Also the general form of the colony. The following is what I gathered so far.

Pimply leathery soft coral (Lobophytum sp.) has short autozooids and pimply siphonozooids. The colony usually looks like a mushroom; with a flat, broad disk attached to a hard surface by a very short, very broad central base. The edge of the disk usually is fringed with long cylindrical finger-like protrusions.
The Pinwheel leathery soft coral (Lobophytum sp.) has short autozooids and siphonozooids. The circular colony usually looks like a mushroom; with a flat, broad disk attached to a hard surface by a very short, very broad central base. On the upper surface, ridges radiate from the centre of the disk.
The Omelette leathery soft coral (Sacrophyton sp.) has longer more slender autozooids and siphonozooids. The circular colony usually looks like a mushroom; with a flat, broad disk attached to a hard surface by a very short, very broad central base.
The Smooth leathery soft coral (Sinularia sp.) only has autozooids and no siphonozooids. Sinularia species have among the greatest variation in colony shapes among soft corals. The colony may be encrusting with ridges, knobs or fingers, or tall with many lobes, branches, or flat disks, leafy or dish-shaped.

Thanks to ID help from Joseph Lai, I think this tiny ferny seaweed might be Bostrychia sp. A golden carpet of this seaweed is often seen on our wild rocky shores, provide food an shelter for all kinds of tiny snails, slugs and creepy crawlies.
Please do let me know if I got any of the identifications wrong!

As usual, I'm way behind on the fact sheets. During our recent field trips, there have been lots of other interesting sightings. Some are first entries to the wild fact sheets for the location. Others are interesting behaviours observed for the first time. There are also lots of interesting video clips! These photos and video clips have been updated on the wild fact sheets. Thanks to all the team members who shared their findings online. Visit their sites for more stories and photos!

Those who went diving in Singapore waters had spectacular sightings too! Check out these blogs for more:

I'd gladly include your sightings in the wild fact sheets. Just email me, Ria at hello@wildsingapore.com



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