top shell snail
seen? This snail with a tooth in its shell opening is commonly
seen on many of our shores. Often seen in groups on boulders, stones
and seawalls on many of our shores. It is more active at night.
3-4cm. Shell thick, an asymmetrical cone with spirals of rounded bumps.
Usually grey or greenish grey. Mono
donta means 'one-toothed'. Indeed, there is a single large tooth-shaped
structure at the shell opening which is white and smooth. Operculum,
thin, made of a horn-like material with concentric rings, yellow.
The flexible operculum allows the animal to withdraw deep into the
coils of the shell. Hopefully, safe from prying
claws of hungry crabs.
Body pale, edge of the mantle fringed with long tentacles. Large foot
pale on the underside, mottled greenish on the upperside. A pair of
long tentacles at the head.
confused with the Turban
snail (Family Turbinidae) which has a shell with more distinct
whorls and a thick, chalky operculum. While many Top snails have a
more conical shell and a thin operculum made of a horn-like material.
Here's more on how to tell apart turban
and top shell snails.
St. John's Island, Aug 05
top shell snails on Singapore shores
Sentosa Serapong, May 16
Photo shared by Ivan Kwan on facebook.
Pulau Sudong, Dec 09
Photo shared by Ivan Kwan on his
- Tan Siong
Kiat and Henrietta P. M. Woo, 2010 Preliminary
Checklist of The Molluscs of Singapore (pdf), Raffles
Museum of Biodiversity Research, National University of Singapore.
- Tan, K. S.
& L. M. Chou, 2000. A
Guide to the Common Seashells of Singapore. Singapore
Science Centre. 160 pp.