15 April 2009

Wildfacts updates: snails, gobies and more

Snails with spurs, assorted fishies got sorted and more marine marvels got figured out during the low tide trips of March.
The most exciting was my first time encounter with the Spurred turban snail (Astraea calcar)!

'Calcar' means 'spur'. And indeed, the shell of this snail has a spiral of blunt spikes. It is a member of the Family Turbinidae, which becomes obvious when we look at its 'door' (operculum) which looks very much like that of the more common Dwarf turban snail (Trochus brunneus).

I also had first time encounters with these mangrove nerites, with all that traipsing into mangroves recently at Pulau Semakau and Berlayar Creek.This one is probably Neritina cornucopia which I thought to call the Black-mouth nerite.
While this one is probably Neritina violacea. Usually referred to as the Violet nerite, but I do think the name Red-mouth nerite is probably easier to remember. I'm still not sure whether these nerite IDs are correct.

Another mangrove-only mollusc that I encountered for the first time at close quarters were these Mangrove helmet snails. These are probably Cassidula aurisfelis. Since 'Auris' means 'ear' while 'felis' means 'cat', I thought it appropriate to call it the Cat's ear mangrove helmet snail.

I suppose the underside of the snail does look a bit like a cat's ear. Let's compare with a real cat's ear...I guess there's some resemblence, though it takes a bit of imagination.

And then there were lots of these beautiful banded ones with pink undersides. These are probably Cassidula mustelina. 'Mustelina' means 'weasel' but I think Banded mangrove helmet snail is more descriptive, since many Singaporeans may not know what a weasel is.

I have found it difficult as a nature guide to explain common names to people who don't know what the common name refers to. For example, fiddler crabs are horribly difficult to explain to people who have no idea what a fiddle is. Would be so much easier to call the crabs say, One-Big-Claw crab, or something like that.

Boon Peiya also shared more insights into the colourful the Face-banded sesarmine crabs that I've been seeing on Pulau Semakau and Sungei Buloh recently. First of all, they are Perisesarma eumolpe and Perisesarma indiarum! The old name was Chiromantes eumolpe.
She also shared photos of how to differentiate the two species, and lots more fascinating information. These have been updated on the page for the Face-banded sesarmine crab.

My adventures with Subaraj and Serin on Pulau Semakau have led me to take a closer look at my photos of the many small mudskippers that lack identifying marks. The Dusky-gilled mudskipper (Periophthalmus novemradiatus) is only positively identified by looking at the underside, to see the blackish area near the gills. For ease of display, I've grouped the larger mudskippers with broad heads on the page for this mudskipper. The IDs of course, remain tentative.While I've grouped the skinnier, smaller mudskippers on the page about the Slender mudskipper (Periophthalmus gracilis). I also realised, after scrutinising photos, that this might be the Common frill-fin goby (Bathygobius fuscus). It has bulging cheeks and a pattern of small white spots regularly spaced on its face and in rows down its body. As well as dark blotches and saddles. It's quite a handsome goby!This dull, sometimes 'spiky', sea cucumber that is commonly seen on Pulau Semakau is probably Stichopus horrens or the Warty Selenka's sea cucumber. I realised this when finding out more about the 'gamat' sea cucumbers of Malaysia that are threatened by over-collection. This is one of the sea cucumbers affected by harvesting of fluids for the traditional tonic called 'Air gamat'.

I've also just uploaded a page of the Hairy spoon seagrass (Halophila decipiens), after Len McKenzie of Seagrass-Watch suggested those I saw at Pulau Sekudu were not just ordinary Halophila ovalis!This seagrass was first reported for Singapore in 2008.

There's lots more sightings to update following the field trips, and many new fact sheets to do and upload. It's amazing how I see something new on every trip to the shore!

1 comment:

LinkWithin

Related Posts with Thumbnails