Tridacna Ruffled Fluted Clamshell Specimen. Enormous display-worthy piece. 

Size: 14 X 8 X 6 in. 

#8560 . 

Tridacna is a genus of large saltwater clams, marine bivalve molluscs in the subfamily Tridacninae, the giant clams. They have heavy shells, fluted with 4 to 6 folds, and the mantle is often brightly coloured. They inhabit shallow waters of coral reefs in warm seas of the Indo-Pacific region, and are popular in marine aquaria, although this popularity has also led to them becoming endangered due to extensive harvesting. They live in symbiosis with photosynthetic algae (zooxanthellae), and although some species are eaten by humans all of the species in the genus Tridacna are protected under the Convention on International Trade of Endangered Species. The name Tridacna arises from Greek words “tri,” meaning three, and “dacno,” meaning bite. In the Ancient Roman text Natural History, Pliny the Elder explained the nomenclature comes from the fact that “they are so large as to require three bites in eating them.” Compared to other clams, the soft mantle that secretes the shell is greatly expanded. The clams even have small lens-like structures called ocelli through which light penetrates. Their large shells, which open to gather nutrients during the day, can close when the clam feels threatened, but fears that divers could be injured by the tough shell are unfounded as it takes a substantial period of time to close, particularly in the largest of the species. Tridacna clams can produce large white pearls with an undulating, porcelain-like surface, which may be described as “non-nacreous pearls,” and their uniqueness and incredible size (with the largest ever discovered weighing over 14 pounds) has helped develop a sustaining farming industry in the Philippines to counteract the near extinction they faced starting in the 1980s. Over a hundred examples of carved Tridacna shells have been found in archaeological expeditions from Italy to the Near East. Similar in artistic style, they were probably produced in the mid 7th Century, made or distributed from the southern coast of Phoenicia. The backs and interior perimeters of the shells show animal, human, and floral motifs, while the interiors typically show recumbent sphinxes. The umbo of the shell is in the shape of a human female or bird’s head, and they were probably used to store eye cosmetics. Today many artisans carve pieces for similar use, although they are much rarer than they once were as the process of revitalizing the species will be a long and difficult one.