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Spider
conch
Lambis lambis
Family Strombidae
updated
Aug 10
Where
seen?
This amazing large snail with spikes on its shell is sometimes seen
on our Southern shores near coral rubble areas. Although large, it
is often overlooked because the upperside of the shell is very well
camouflaged. Elsewhere, it is considered common on reef flats and
on coral-rubble bottoms or in mangrove areas, usually associated with
fine red algae on which it feeds. Often occurring in colonies. In
shallow water, from low tide levels to a depth of about 5 m.
Features: 10-20cm long. Thick
heavy shell with six spines on the flared lip. The upperside of the
shell is usually encrusted and thus blends with the surroundings.
The shell opening is pearly and pinkish with orange or yellow tints.
Part of the body is olive-brown with white spots. It has large eyes
on long stalks and a thick siphon. Like other conch snails, it has
a curved, knife-shaped operculum attached to a long strong foot. This
is used by the animal to 'hop' along the surface. The spines on the
shell improves stability and prevents the snail from toppling over
as it hops.
The long spines on its shell are found only on adults and gives it
its common name. The shell of young snails look like large volutes.
Male and female snails look very different. The shell of the males
usually smaller and with shorter spines on the outer lip. Mama snails
lay bright orange egg strings.
What does it eat? It grazes on
fine red algae.
Human uses: Where common, it is
often collected for food by coastal populations, and the shell used
in shellcraft. Appears in markets in the northern Philippines and
in Fiji Islands.
Status and threats: The spider
conch is listed as 'Vulnerable' on the Red List of threatened animals
of Singapore. According to the Singapore Red Data Book: it is "rare
and no longer as abundant as in the 1960's". Like other creatures
of the intertidal zone, they are affected by human activities such
as reclamation and pollution. Trampling by careless visitors and over-collection
for their shells can also have an impact on local populations.
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Pulau Hantu, Aug 04

Close up of animal.

Knife-like operculum attached to
a long muscular foot.
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Spider
conch snails on Singapore shores
Camouflaged upperside
Pulau Jong, Aug 06
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Underside.
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Knife-like operculum
on strong foot.
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A young snail that hasn't developed
spines on its shell yet.
Pulau Jong, Jul 07
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A young snail that hasn't developed
spines on its shell yet.
Tanah Merah, Feb 12
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A young snail?
Pulau Semakau, Nov 09
Photo shared by James Koh on his
blog.
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Laying bright orange egg string.
Terumbu Hantu, Apr 12
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Orange egg string.
Terumbu Hantu, Apr 12
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Orange egg string.
Terumbu Hantu, Apr 12
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| Links
References
- 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.
- Tan, Hugh
T.W. L.M. Chou, Darren C. J. Yeo and Peter K.L. Ng. 2007. The
Natural Heritage of Singapore. Second edition. Prentice
Hall. 271 pp.
- Abbott, R.
Tucker, 1991. Seashells
of South East Asia
.
Graham Brash, Singapore. 145 pp.
- 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.
Nature Society (Singapore). 285 pp.
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