Tuesday, December 18, 2012

Tusk Shells (Phylum Mollusca: Class Scaphopoda) of Singapore

A scaphopod (phylum Mollusca, class Scaphopoda), is a soft-bodied animal with a a bilaterally symmetrical, tubular, tapering and curved shell which resembles a miniature elephant's tusk, and hence they are also often called "tusk shells". However, unlike a tusk, both ends of the shell are open.  The name "scaphopoda" means "shovel-footed", refering to the long, pointed foot of most tusk shells.

Tusk Shell (Class Scaphopoda)
The animal is attached to the shell with the muscles near the posterior end (the narrower tip). They have no eyes, and the mouth is located the base of the foot. They have filaments for seizing food (usually microscopic organisms) at the corners of the mouth. Like most other molluscs, they have a radula in the mouth, which is basically a tongue-like structure with rows of teeth. They are usually found on sandy or muddy sea bottom.

Tusk Shell (Class Scaphopoda)
The opening at the larger end is the main or anterior aperture, while the smaller opening is known as the apical aperture. They are usually identified to the species by looking at the structure of the anterior aperture.

Tusk Shell (Class Scaphopoda)
The shells were used as a form of currency by natives in North America in olden days, and also for personal adornment.

Tusk Shell (Class Scaphopoda)
Unfortunately at the moment, the identification of tusk shells is still beyond me, and hence all the above shells are not identified.

  • Rogers, J. E., 1908. The Shell Book - A Popular Guide to a Knowledge of the Families of Living Molluscs, and an Aid to the identification of Shells Native and Foreign. Charles T. Branford Co., Publishers. Boston, Massachusetts. 485 pp.
  • Tan, L. W. H. & P. K. L. Ng. 1988. A Guide to Seashore Life. Singapore Science Centre. Singapore. 160 pp.

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