seen? These snails with top-shaped shells are commonly
seen on many of our rocky shores including man-made sea walls. Top
shell snails are not as well adapted to dry conditions as the Nerites and Periwinkles, and
are thus generally found closer to the low water mark.
Features: 3-15cm. Shell thick.
Some are shaped like a conical top, the spinning toy. The operculum
is circular with concentric rings usually clearly visible. It is made
of a thin, horn-like material and is flexible. This allows the snail
to withdraw deep into the coils of the shell, hopefully out of the
reach of crab pincers. The shell is sometimes covered in encrusting
lifeforms. In some species, the body mantle of the living animal is
fringed with long tentacles.
Sometimes 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.
The Spotted top shell snail has a large foot with tentacles
fringing the body mantle.
Labrador, May 05
The Toothed top shell snail also has a large foot with tentacles
fringing the body mantle.
St. John's Island, Aug 05
Tiny button snails have a long mobile foot and tentacles fringing
the body mantle.
East Coast, Aug 12
|What do they eat? Top shells graze the algae that thrive
on the rocks, scraping this off with their radula.
Human uses: The shell
is lined with mother-of-pearl. Larger species are collected for food
and their shells that are made into ornaments and pearl buttons. This
is still a significant industry in some Pacific Islands and effort
is being made to establish a susbtainable method of farming these
Status and threats: Button
snails are listed as 'Vulnerable'
on the Red List of threatened animals of Singapore.
shell snails on Singapore shores
Trochidae recorded for Singapore
Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist
of The Molluscs of Singapore.
in red are those listed among the threatened
animals of Singapore from Davison, G.W. H. and P. K. L. Ng
and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened plants
and animals of Singapore.
+Other additions (Singapore BIodiversity Records, etc)
shells seen awaiting identification
Species are difficult to positively identify without
On this website, they are grouped by external features for convenience
paradoxum (Orange-mouth top shell snail)
Clanculus granosus=^Clanculus bronni
Monodonta labio (Toothed top shell
Trochus maculatus (Spotted top
(Button snail) (VU: Vulnerable)
|| Minolia biangulosa
Minolia holdsworthana=^Pseudominolia musiva
- Toh Chay Hoon, Tan Siong Kiat & Martyn E. Y. Low. 10 January 2014. A record of Stomatella impertusa in Singapore. Singapore Biodiversity Records 2014: 19
- 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.
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore
Red Data Book: Threatened plants and animals of Singapore.
Nature Society (Singapore). 285 pp.
- Abbott, R.
Tucker, 1991. Seashells
of South East Asia.
Graham Brash, Singapore. 145 pp.