| Grooved carpet shell | |
|---|---|
 | |
| Pleistocene fossil shell from the North Sea | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Order: | Venerida |
| Family: | Veneridae |
| Genus: | Ruditapes |
| Species: | R. decussatus |
| Binomial name | |
| Ruditapes decussatus | |
| Synonyms[1] | |
Thegrooved carpet shell, orPalourde clam,[2]Ruditapes decussatus, orVenerupis decussatus, is aclam (bivalvemollusc) in thefamilyVeneridae. It is distributed worldwide and is highly prized due to its ecological and economic interest. It has been proposed as abioindicator.
This species is one of the most popular and profitable mollusks of lagoonal and coastal sites in the Mediterranean and adjoining Atlantic coast where it has been collected for generations for culinary use. It is consumed fresh and canned. Several dishes likeSpaghetti alle vongole and the PortugueseAmêijoas à Bulhão Pato, make use of it.[3]
Theshell is broadly oval to quadrate with the umbones distinctly anterior. The posterior hinge line is straight, the posterior margin truncate, and the anterior hinge line grades into the down-sloping anterior margin. It is prominent posteriorly, where the shell is conspicuously decussate. The surface has asculpture of fine concentric striae and bolder radiating lines. Growth stages are clear. The lunule and escutcheon are poorly defined. Each valve has three cardinal teeth: the centre one in the left valve, and centre and posterior in right are bifid. The pallial line and adductor scars are distinct. The pallial sinus is U-shaped, not extending beyond the midline of the shell, but reaching a point below the posterior part of the ligament. The lower limb of the sinus is distinct from the pallial line for the whole of its length. The inner surfaces of the shell are glossy white, often with yellow or orange tints, and with a bluish tinge along the dorsal edge. The overall color is cream, yellowish, or light brown, often with darker markings.[4]
Ruditapes decussatus
Right and left valve of the same specimen:
Ruditapes decussatus floridus
Right and left valve of the same specimen:
Despite improper management in the past, some regions in the Atlantic coast of theIberian Peninsula, including Portugal'sAlgarve andSpain'sGalicia, and Spain'sMediterranean basin, as well asIreland, currently have solid populations ofRuditapes decussatus.[4][5][6]
Ruditapes decussatus is cultured from theAtlantic coast ofFrance,Spain,Portugal and in theMediterranean basin. It is often grown with otherbivalves (Venerupis pullastra,Venerupis rhomboides,Venerupis aurea,Dosinia exoleta andTellina incarnata). Their main predators are shore crabs (Carcinus maenas); starfish (Asterias rubens andMarthasterias glacialis); gastropods (Natica sp.); and birds (Larus sp). An individualCarcinus maenas (6.5 cm width) can consume 5 or 6 clams per day. Marine aquaculture production of grooved carpet shell in 2003 was 3,007 t in Portugal, which excludes non-aquaculture harvesting of the species.
Between 1997 and 2001 totalaquaculture production varied between 3,700 and 4,900 tonnes, from five countries. Most was produced byPortugal butFrance andSpain have also been significant producers; however, the contribution from France is now much lower than before; in 1995 it was by far the leading producer with nearly 5,200 tonnes but in 2004 it produced only 475 tonnes. Global production seems to be declining; in 2004 it was only 2,700 tonnes but theUnited Kingdom had appeared as a minor producer.
It is consumed fresh and canned.[4]
Commercialmollusks | ||
|---|---|---|
| Marinegastropods |  | |
| Land and freshwater gastropods | ||
| Free-swimming marinebivalves | ||
| Infaunal bivalves | ||
| Sessile bivalves | ||
| Freshwater bivalves | ||
| Cephalopods | ||
| Techniques | ||
