Saturday, October 20, 2012

Tritons & Trumpet Shell (Phylum Mollusca: Family Ranellidae) of Singapore

Commonly called the tritons or trumpet snails, the ranellids are characterised by thick shells with a long siphonal canal extending from their backends. Larger species were hence used as trumpets in olden days by blowing into the siphonal canal. Some species may come with not more than two strong ridges (varices) running along the sides of the shell. They usually have corneous opercula. Trumpet Snails generally can secrete a paralyzing saliva to stun their prey. Personally, I prefer calling them trumpet snails rather than tritons, to avoid confusion with the well-known Triton's Trumpet (Charonia tritonis) which is found regionally, but not seen so far in local waters.

I have only photographed two species of ranellid snails on our shores so far (thanks to Siong Kiat who gave tips on how to identify them!). You may want to take a look at my diagram on the parts of a snail's shell if you are not familiar with the names of the parts, so as to better understand the terms used below.

Gyrineum natator
Gyrineum natator, or what I call the Rock Trumpet, is usually found under rocks. It has an enlarged body whorl, two very strong varices (obviously ridges running along the length of the shell), and spiral cords marked with some nodules. "Natator" means "swimming" or "floating", but I have not seen this snail swimming before, so I have no idea why it is so named.

The aperture is whitish, and a moderately long and deep siphonal canal. Studies suggest that it feeds on bivalves, such as oysters.

Linatella caudata
Linatella caudata, or what I call the Hairy Trumpet due to the hairy appearance, is usually found in seagrass meadows. It lacks obvious varices, but, like the previous species, also has an enlarged body whorl and a moderately long siphonal canal. I have seen it feeding on Fan Shells (Pinna bicolor).

Linatella caudata
The shell is solid and thick, and the body of the snail is brownish with black spots.

Linatella caudata
I have also seen it laying eggs capsules in the shape of a hemisphere.

  • Abbott, R. T., 1991. Seashells of Southeast Asia. Graham Brash, Singapore. 145 pp.
  • Beechey, D., 2012. The Seashells of New South Wales. Retrieved Oct 19, 2012, from
  • Gladys Archerd Shell Collection at Washington State University Tri-Cities Natural History Museum. 2008. Retrieved September 26, 2012, from
  • Oliver, A. P. H., 2012. Philip's guide to seashells of the world. Philip's, London. 320 pp.
  • Tan, S. K. & H. P. M. Woo, 2010. A preliminary checklist of the molluscs of Singapore. Raffles Museum of Biodiversity Research, National University of Singapore, Singapore. 78 pp. Uploaded 02 June 2010.
  • World Register of Marine Species. 2012.  Retrieved Oct 19, 2012, from

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