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Phylum Mollusca > Class Bivalvia
Thorny oyster
Spondylus sp.*
Family Spondylidae
updated May 2020
Where seen? This rather large clam with spikes is sometimes seen near reefs, stuck to rocks or dead corals. It is not a true oyster, which belong to Family Ostreidae.

Features: 8-10cm.
The two-part shell is thick and heavy. The lower (right) valve is cemented very firmly to the hard surface and is more convex (like a cup). The upper (left) valve is rather flat, like a lid, and covered with flat short spines. The animal has short tentacles and eyes at the margin of the body mantle.

What do they eat? Like most other bivalves, it is a filter feeder. When submerged, it opens its valves slightly and sucks in a current of water. It uses its enlarged gills to sieve food particles out of this current. When the tide goes out, it clamps up the valves tightly to prevent water loss.

Human uses: Collected for for food and the shell trade by coastal dwellers. Their shells may also be used in shellcraft or to make lime.

Pulau Berkas, Jan 10

Pulau Berkas, Jan 10

Mantle revealed in this submerged clam.
Tanah Merah, Dec 10

*Species are difficult to positively identify without close examination.
On this website, they are grouped by external features for convenience of display.

Thorny oysters on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Terumbu Pempang Tengah, May 21
Photo shared by Vincent Choo on facebook.

Beting Bemban Besar, Jun 21
Photo shared by Vincent Choo on facebook.

Family Spondylidae recorded for Singapore
from Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore.

  Family Spondylidae
  Spondylus croceus
Spondylus echinatus
Spondylus longitudinalis
Spondylus regius
Spondylus versicolor

  • Family Spondylidae in the Bivalves 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.
  • Abbott, R. Tucker, 1991. Seashells of South East Asia. Graham Brash, Singapore. 145 pp.
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