Shellfish Worksheet

by Ted Garside

(Based on a photocopy of a document in the archives; original hand-drawn illustrations are included below when the scanned version was clear; in other instances, new illustrations have been used below. This document is also available as a PDF and a MicroSoft Word document. )

This worksheet is meant as a simple guide to the more common shells you will find along the shore line between the high and low water marks. It is not meant to be a definitive guide but merely an outline to get you started.

As with Francis Buckley’s worksheet we will record the finds and produce a consolidated list of the species we find and publish it in the Newsletter.

Again remember, after you have searched under rocks etc. please TURN THE ROCKS BACK.

There are two main groups of shellfish (molluscs):

Gastropods Gastropod drawing These animals have a single, large shell which may be spirally coiled, dome shaped, cap shaped or cone shaped. Spirally coiled shells are usually twisted into a helix but some are coiled into a flat plane, and in others the helix opens out into an irregular shaped tube. The last section of the soil, the body whorl, is the largest and is where the animal lives. The colors can be very varied even within the same species or family.

Bivalves Bivalve drawing These animals have a shell consisting of two halves joined by flexible muscles in the form of a hinge. The muscles open and shut the two halves of the shell. When the animal dies the two halves become separated, although you may be lucky and find a specimen with them still joined.

For the sake of completeness there are two other groups of molluscs:

Chitons Chiton drawing These molluscs Francis has already mentioned in the previous section. They are easily recognized by the eight platelets which make up the shell.

Tusk Shells Tusk shell drawing These are hollow, tubular, tusk-like shells. These animals usually live in deep water, but you may be lucky and find an empty shell washed up on the beach.

Gastropods

Family: Olividae (Olives)			A smooth, glossy shell with a large cylindrical whorl and a small conical spire at one end. They come in many colors with usually fine purple to brown zigzag markings. Carnivorous, they feed at night and capture their prey by enfolding it in their foot.
Family: Cypraedidae (Cowries)			The Cowries are probably the most colorful of all the shells and as such are very popular with collectors. It is impossible to describe the range of colors. The best distinguishing feature is the long narrow opening with serrated lips running the whole length of the underside.
Family: Conidae (Cone shells)			The Cones vie with the Cowries to be the most popular collectors’ items. Their range of patterning is extensive on varied base colors. As their name implies they are cone shaped with a flattish top and a small pointed spire. They mainly live in the inter-tidal area in rock crevices. They are carnivorous and have a sting with which they kill their prey. The venom in the sting of some members of the family can prove fatal to humans. *Conus Geographus* is the most dangerous. The sting is located in the tongue, or proboscis, located in the ‘small’ open end. Always pick up the shell by the big end. NEVER PUT A LIVING CONE IN YOUR POCKET.
Family: Fasciolariidae (Spindle shells)			Graceful, long shells with high pointed spires, small apertures, and an elongated siphonal canal. Sometimes called ‘Tulip’ shells. *Fusinus Aribicus* is pale cream to brown and very common to the UAE. A real find would be *Fusinus Townsendi*, a beautiful pale ivory to opalescent white, which is quite rare in this area.
Family: Architectonicidae (Sundial shells)			One has only to turn this shell upside down to see why it is called the Sundial. It is distinctively round with a conical spiral and pronounced symmetrical markings. The deep hole in the middle of the shell is used as an incubator for the female’s eggs.
Family: Turritellidae (Turret shells)			A slender, elongated shell with a pointed apex and 10-12 convex whorls. The aperture is round with a thin lip and no siphonal canal. Very common in this area. Usually pink to light brown in color.
Family: Terebridea (Auger shells)			A slender, elongated shell not unlike the Turret shells. It usually has more whorls than the latter, about 15. It has a small aperture and is distinctive in having a small siphonal canal twisted to the left. There is also a wide spiral band below each whorl (the suture) which gives the appearance of having twice as many whorls. Color usually pinkish grey to blue-cream. Ivory ones are rare.
Family: Patellidae (Limpets)			A low cone shaped shell, with no spire and a round to oval base. The apex is more or less at the cone center. The outside of the shell has many prominent radial ridges and the inside surface is very glazed. Hard to remove from its rocks.

Bivalves

Family: Cardiidae (Cockle shells)			Pale yellow to white, a strong ‘inflated’ look with serrated edges. Often has concentric rows of reddish-brown spots. Very common and found worldwide.
Family: Pectinacea (Scallops)			An almost round shell, with the hinge formed in the shape of two unequal wings. The color varies from deep red to white and can be in concentric bands or rays from the hinge.
Family: Pinnidae (Pen shells)			A rather large fan shaped shell with color ranging from grey-brown to black. They are very fragile, and because of this it is very rare to find a whole specimen.
Family: Spondylidae (Thorny oyster)			A large almost round shell, very thick with small wings at the hinge. The shell has many long thin spines and ranges in color from white with pink beaks to pale red. A prominent feature is the hinge with two interlocking and well fitting teeth.
Family: Pteriidae (Pearl oysters)			A very insignificant dull looking shell until it is opened. The interior is lined with mother of pearl.
Family: Mactridae (Surf clams)			These are generally smooth glossy shells, oval or ‘rounded triangle’ in shape. The markings are fine concentric growth lines with usually radiating lines of a different color. The range of colors is quite extensive, which makes them very attractive to collect.

Gastropods		These animals have a single, large shell which may be spirally coiled, dome shaped, cap shaped or cone shaped. Spirally coiled shells are usually twisted into a helix but some are coiled into a flat plane, and in others the helix opens out into an irregular shaped tube. The last section of the soil, the body whorl, is the largest and is where the animal lives. The colors can be very varied even within the same species or family.
Bivalves		These animals have a shell consisting of two halves joined by flexible muscles in the form of a hinge. The muscles open and shut the two halves of the shell. When the animal dies the two halves become separated, although you may be lucky and find a specimen with them still joined.

Chitons		These molluscs Francis has already mentioned in the previous section. They are easily recognized by the eight platelets which make up the shell.
Tusk Shells		These are hollow, tubular, tusk-like shells. These animals usually live in deep water, but you may be lucky and find an empty shell washed up on the beach.