learn only 3 things about them ...
thick, chalky operculum resembles a cat's eye.
pretty shell is often hidden under encrusting growths.
Some are threatened by over-collection.
seen? These tough snails are commonly seen on many of our
rocky shores including on man-made sea walls. Smaller ones are also
found under stones. Turban shells are not as well adapted to dry condictions
as the Nerites and Periwinkles,
and are thus generally found closer to the low water mark.
Features: 3-5cm. In some species,
the shell does resemble an elegant turban! Although the Latin 'turbo'
actually refers to a top, the spinning toy. The shells of are sometimes
covered in encrusting lifeforms so that the texture and colours are
Cat's eye: In most of the common
turban snails, the operculum is smooth and hemi-spherical (rounded)
on the side facing outwards. This possibly makes it difficult for
crabs to get a grip and pry out the snail. The shape and markings
of the operculum makes it look like a cat's eye so that is what it
is sometimes called.
Although their shells may appear boring and dull, the living animal
can be in bright shades of green or blue. Under the large shell, peep
little eyes and long tentacles.
Sometimes confused with the Top
shell snail (Family Trochidae) has a more pyramidal shell and
a thin operculum made of a horn-like material. While the turban shell
snail has a shell with more distinct whorls and a thick, chalky operculum.
Here's more on how to tell apart turban
and top shell snails.
What do they eat? Turban shells
graze the algae that thrive on the rocks, scraping this off with their
Human uses: In our region, the
larger turban snails are collected for food and their mother-of-pearl
shell. The large Giant green turban snail (Turbo mamoratus)
is collected for food and its shell carved into ornaments and jewellery.
In recent years, heavy commercial exploitation has depleted local
Status and threats: The Tapestry
turban shell (Turbo petholatus) is listed as 'Endangered' on
the Red List of the threatened animals of Singapore. It has a smooth,
brightly coloured shell in brown, green and yellow fine lines. According
to the Singapore Red Data book: "Although never abundant, this
species could be found up until the early 1970's but is now extremely
rare. It needs to be protected from shell collectors".
Labrador, May 05
Cyrene Reef, Jul 12
Dolphin shell snail
Tanah Merah, Oct 09
Sometimes, only the operculum
is seen on the shore.
Two different kinds of turban snails.
More easily distinguished by their operculum.
snails on Singapore shores
operculum smooth, green centre with white and yellow margins,
Spiral ribs smooth without scales.
operculum bumpy, green centre with
white and greyish margins.
Spiral ribs rough with tiny scales.
Turbinidae recorded for Singapore
Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist
of The Molluscs of Singapore.
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.
Turban Shell (Turbo brunneus)
Tan, Leo W. H. & Ng, Peter K. L., 1988. A
Guide to Seashore Life. The Singapore Science Centre,
Singapore. 160 pp.
Turbinidae on The Gladys Archerd Shell Collection at Washington
State University Tri-Cities Natural History Museum website: brief
fact sheet with photos.
Humble Operculum: photos and facts just some beautiful opercula
of snails, many of which are turban shells, with photos also of
their shells. A fascinating site.
- Family Turbinidae
the Gastropods section by J.M. Poutiers in the FAO Species Identification
Guide for Fishery Purposes: The Living Marine Resources of the
Western Central Pacific Volume
1: Seaweeds, corals, bivalves and gastropods on the Food and
Agriculture Organization of the United Nations (FAO) website.
- 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.