Conchology
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Conchology is the scientific, semi-scientific, or amateur study of the shells of mollusks. It can include the study of the shells (i.e. the calcareous exoskeletons of the phylum mollusca, which includes the operculum of the organism where one is present - a "trap door" the animal uses to protect itself from predators and extreme conditions) of land, freshwater, and marine mollusks.

Conchology is often confounded with shell collecting in general. However, many collectors are primarily concerned with the perceived beauty (aesthetic value) and the extreme variability of shapes, colors and patterns of shells, as opposed to systematic study of these natural history objects. One does not have to be a shell collector in order to be a conchologist: this simply requires access to private and/or institutional collections. The two terms can therefore regarded as distinct, although there is some debate in the conchological community about this matter with many considering all collectors regardless of motivation, to be conchologists of one kind or another.

Conchology can be viewed as a branch of malacology, which is the study of molluscs (UK spelling) or mollusks (US spelling) as whole organisms, not just their shells - and indeed, conchology predated malacology as a field of study by many years: ever since at least the time of the ancient Egyptians (reference needed), people have admired, collected and no doubt studied mollusc shells.

That having been said, the term "conchology" is used by some (especially in Europe) to mean the same thing as "malacology", thus when using the term it is often useful to "operationally define" what you are refering to.

In current times, conchology (i.e. in its more constrained sense) is often seen as rather archaic: it is sometimes considered to be lacking in scientific rigor because of the limitation of looking only at the shell of an organism.

In the scientific or natural history sense, conchologists study these animal shells in order to gain an understanding of the diverse and complex taxonomy of mollusks. As with many other taxonomic fields, molluscan taxonomy is in a constant state of flux.

A vendor in Tanzania sells seashells.
A vendor in Tanzania sells seashells.

Conchology is sometimes considered to include the shells/tests of other marine invertebrates, such as brachiopods, echinoderms, cnidarians, and crustaceans.

Conchology deals with all mollusk shells, however, squid and other cephalopods do not have outer shells (with the exception of the Nautiloidea), having evolved just to have an internal bone or shell, used for buoyancy or support. Some groups (such as the aptly named nudibranchs) have lost their "skeleton" (internal and/or external) altogether, while in some it has been replaced by a cartilaginous support structure. Because of this, conchologists deal mainly with the molluscan orders which constitute the gastropods (snails), bivalves, Polyplacophora (chitons) and Scaphopoda (tusk shells).

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History of Conchology

Shell collecting, the "ancestor" or precursor of conchology, most likely goes back for as long as there have been people and beaches: someone walking on the beach would pick up a shell for its beauty and maybe go out the next day to look for more. The fact that molluscs have probably been used by primates as a food source even before humanoids evolved added to its commonality. There have been seashell necklaces found from the Stone Age, some of which were found in areas removed from the ocean, indicating that they were traded. Shell necklaces and jewelry are found at almost all archaeological sites, including at ancient Aztec ruins, digs in ancient China, the Indus Valley, and Native American sites. During the Renaissance, people began taking interest in natural objects of beauty to put in wunderkammern. Because of their attractiveness, variety, durability and ubiquity (shell-bearing molluscs can be found from nearly all marine and a huge variety of land and fresh water habitats) shells became a large part of these collections. Towards the end of the seventeenth century, people began looking at shells with scientific interest. Lister in 1685-1692 published Historia Conchyliorum, which was the first comprehensive conchological book, with over 1000 engraved plates.

A plate from Lister’s book, showing what he calls buccinis shells
A plate from Lister’s book, showing what he calls buccinis shells

George Eberhard Rumpf, or Rumphius, (1627-1702) was another important early conchologist. He published the first classifications of molluscs into different groups; he suggested "Single Shelled Ones" (Polyplacophora, limpets, and abalones), "Snails or Whelks" (Gastropods), and "Two-Shelled Ones" (Bivalves). Rumphius first published many of the names and taxonomic terms adopted by Linnæus, and continued to do important scientific work even after he went blind, working by feel.

The study of shells & molluscs, like most other branches of zoology, was revolutionized by the "father of modern taxonomy" Swedish naturalist Carolus Linnæus and his system of nomenclature. It is now commonly held that 683 of the 4000 or so animal species he described, are now considered to be molluscs (see Harry G. Lee's excellent article at the Jax Shells website (which contains many well researched conchological articles) for details), although he placed them in several phyla at the time.

After Linnæus, conchology/malacology became an official branch of zoology. There have been many prominent conchologists in the past few centuries; the Sowerby family were famous collectors and shell dealers, as well as being noted for their superb illustrations; John Mawe (1764 – 1829) produced arguably the first conchology how-to guide - The Voyager's Companion or Shell-Collector's Pilot as well as The Linnæan System of Conchology; Hugh Cuming (1791-1865) also is famous for his huge collection and number of new species discovered. Another fundamental work was American Conchology, or Descriptions of the Shells of North America, Illustrated From Coloured Figures From Original Drawings, Executed from Nature (six volumes, 1830-1834), written by Thomas Say.

Perhaps the most prominent conchologist of the 20th century was R. Tucker Abbott. Author of dozens of books on conchology, Senior Advisor, Founding Director, and finally Museum Director of the Bailey-Matthews Shell Museum, Abbott brought the world of conchology to the public. His most prominent works are "American Seashells" 1955 & 1974, Seashells of the World, 1962, and The Kingdom of the Seashell, 1972. See Category:Conchologists and Guido Poppe for others. Many of the finest collections of seashells are in private hands. John du Pont, and Jack Lightbourne, among others, are known for extensive collections. Emperor Hirohito of Japan also amassed a huge collection, and was a competent and respected amateur conchologist. That said, John DuPont donated his shell collection to the Delaware Museum of Natural History (DMNH) in 1984, and by far the world's largest assemblage of mollusc shells is housed at the Smithsonian Institution, which has millions of lots and perhaps 50,000 species, versus perhaps 35,000 species for the largest private collections.

Uses of shells

Shells have been collected for millennia, but not just for their beauty.

  • Molluscs, especially bivalves such as clams and mussels, have been an important food source for many different peoples around the world; one example of this is Midden heaps in North American archeology. Other molluscs commonly eaten include octopuses and squid, whelks, oysters, and scallops.
  • Shells have also been used as currency (ie, as a medium of exchange) in various places, including many Indian and Pacific Ocean islands, North America, Africa and the Caribbean. The most common shells to be used as currency have been Cypraea moneta Linne, the “money cowry”, and certain tusk shells, such as those used in North Western North America for many centuries. As well, the Native American wampum belts were made of the shell of the quahog mollusc. See Shell-money for more information. It is of historic interest that the Dutch East Indian Company, a major force in the colonization of the Indian and Pacific Oceans, amassed a large portion of its vast fortune via trading shell money of the species Cypraea moneta L., and C. annulus, for commodities such as spices, exotic animals and gemstones considered valuable in Europe at the time.
  • Shells have often been used as tools due to their variety of shapes. Giant clams (Family Tridacnidae) have been used as bowls, and when big enough, even as bathtubs and baptismal fonts. The bailer volute is so named because Native Australians would use it to bail out their canoes. Many bivalves were used for scrapers, blades, clasps, and other such tools, due to their shape. Some gastropods have been used for oil lamps, the oil being poured in the cavity and the siphonal canal being a perfect holder for the wick.
  • Shells play a part in religion and spirituality, as well. In Botticelli’s Venus, the goddess Venus (goddess) is depicted as rising from the ocean on a scallop shell. The scallop shell is also considered the symbol of Saint James the Great. In Hinduism, the left-handed Chank shell is considered sacred to the god Vishnu. One who finds a left-handed Chank shell (one that coils to the left) is sacred to Vishnu, as well. The Chank shell plays an important role in Buddhism, as well. Cowries were often considered symbols of female fertility, as the shape of the underside of the shell has a resemblance to a vulva. In Santeria, shells are used for divination purposes.
  • Shells also have been used as musical instruments, usually trumpets; the most prominent examples are the Triton shell (Charonia tritonis L.), used as a trumpet in Melanesian and Polynesian culture, and the Queen Conch (Strombus gigas L.), also often used as a trumpet.
Some wool dipped in techelet solution, from the Murex trunculus, turning blue in the sunlight outside P'til Techelet in Israel.
Some wool dipped in techelet solution, from the Murex trunculus, turning blue in the sunlight outside P'til Techelet in Israel.
  • Shells have a place in personal adornment, often being used as jewelry. Shell necklaces have always been very popular, and have been found in Stone Age graves as far inland as the Dordogne Valley in France. The Bullmouth Helmet was used to make cameos, and mother of pearl, from abalones or other bivalves, has often been used as decoration - for example, Pearly Kings and Queens wear buttons made of mother-of-pearl.
  • For decoration. For example, "Sailor's Valentines" were late nineteenth century decorative keepsakes which were made in the Caribbean, and which were often purchased by sailors to give to their loved ones back home. They consisted of elaborate arrangements of seashells glued into attractive symmetrical designs, which were encased on a wooden (usually octagonal) hinged box-frame. The patterns used often featured heart-shaped designs, or included a sentimental expression of love spelled out in small shells.
  • Some shell byproducts have also been used in industrial processes. The pen shell’s byssus was used to make rare, very fine, fabric reserved for royalty. Royalty also got the benefit of another molluscian byproduct: Tyrian purple, made from the ink glands of murex shells. It is similar to the t’khelet blue, made from Murex trunculus, used in tzitzit.
  • Finally, one of the most significant shell by-products are pearls, particularly the ones created by several species of pearl oysters. Many species of molluscs including gastropods also produce some kind of pearl. Indeed there is currently a huge trade in the pearls of fresh-water bivalves, although these pearls are almost never valued as highly as valuable as pearls from the saltwater pearl oyster.

Applied conchology

Many conchologists are employed in the study of molluscs that are directly beneficial or harmful to humans. The study of beneficial molluscs, such as bivalves used for food like clams and mussels, or pearl oysters, is primarily focused on their ecology and life habits, the primary concern being the understanding of how to raise them and make them more productive.

Conversely, much of the study of harmful molluscs is focused on their physiology, with the goal of developing controls that are effective while minimizing undesirable side effects. One example of a harmful "introduced" & invasive mollusc is the zebra mussel, which has spread throughout North America, costing billions of dollars. Considerable recent effort have gone into finding biological controls such as species-specific parasites and diseases, as well as genetic controls.

Organizations

Like other scientific specialties, conchologists have a number of local, national, and international organizations. There are also many organizations specializing in specific subareas.

Museums

Many museums contain very large and important mollusc collections.

Identification of molluscs

Molluscs are usually identified by consulting general or regional shell collecting guides (an example of a general guide is the Compendium of Seashells, by R.T. Abbott and P. Dance), and specific scientific books on different taxa of shell-bearing molluscs (monographs) or "iconographies" (limited text - mainly photographs). The identifications are generally achieved by examining illustrations and written descriptions, rather than by the use of Identification keys as is more often the case in identifying plants. This is because the great amount of variability within many species and families makes the construction of truly useful keys extremely difficult. Because the phylum Mollusca contains a very large number of species and the characters separating them are constantly being debated, identification of some individual species is often very difficult even for a specialist.

Numerous smaller and more obscure mollusc species are yet to be described. In other words they have not yet been differentiated from similar species and assigned scientific (binomial) names in articles in journals recognized by the International Committee on Zoological Nomenclature (ICZN) by scientists. Large numbers of new species are published in the scientific literature each year. There are currently an estimated 100,000 species worldwide.

Fake Shells

Shell collectors who purchase shells from dealers may sometimes encounter shells which have been altered to represent new species, rare color varieties, and so on. For some examples see [1]

Depictions of Molluscs

Shells have been featured on over 5,000 different stamps. This website has a gallery of the stamps, with pictures.

Shells have also been featured on many coins, including those of The Bahamas (1974), Cuba (1981), Haiti (1973), Nepal (1989) and The Philippines (1993).

Sources

External links
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