Sea snails are slow-moving marine gastropod molluscs , usually with visible external shells, such as whelk or abalone . They share the taxonomic class Gastropoda with slugs , which are distinguished from snails primarily by the absence of a visible shell .
15-538: Desmopteridae is a family of pelagic sea snails or "sea butterflies", marine gastropod mollusks in the superfamily Cymbulioidea . This family has no subfamilies (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005 ). Desmopterus Chun, 1889 is the type genus of the family Desmopteridae. The species are protandric hermaphrodites . There is no shell, no protoconch and no longer any supporting tissue. The body consists almost completely of
30-450: A bivalve ; this family is sometimes called the "bivalved gastropods". Their shells are found in a variety of shapes and sizes, but are normally very small. Those living species of sea snails range in size from Syrinx aruanus , the largest living shelled gastropod species at 91 cm (36 in), to minute species whose shells are less than 1 mm at adult size. Because the shells of sea snails are strong and durable in many cases, as
45-401: A group they are well represented in the fossil record . The shells of snails are complex and grow at different speeds. The speed of growth is affected by a few variables such as the temperature of the water, depth of the water, food present for the snail, as well as isotopic oxygen levels. By looking at the composition of aragonite in the growth layers of mollusks you can predict the size
60-581: A number of Middle Paleolithic sites, and are considered a key piece of evidence for the theory that early anatomically modern humans in Africa and the Levant were more culturally sophisticated than had previously been thought. In some cases shells had been transported a considerable distance from the species' natural habitat. One example is the site of Oued Djebbana in Algeria, for example, where an N. gibbosulus bead
75-407: A thick layer of nacre and have been used as a source of mother of pearl . Historically, the button industry relied on these species for a number of years. The shells of sea snails are used for protection by many kinds of hermit crabs . A hermit crab carries the shell by grasping the central columella of the shell using claspers on the tip of its abdomen. Shell jewelry Shell jewelry
90-476: Is jewelry that is primarily made from seashells , the shells of marine mollusks . Shell jewelry is a type of shellcraft . One very common form of shell jewelry is necklaces that are composed of large numbers of beads , where each individual bead is the whole (but often drilled) shell of a small sea snail . Numerous other varieties of shell jewelry are made, including bracelets and earrings . As well as sea snail shells, shell jewelry also sometimes uses
105-421: Is part of some sea snails. In recent times, inexpensive shell jewelry is often found at tropical beach destinations, where it is offered to tourists as informal wear, or as a souvenir . However, shell jewelry has a very ancient past, and is of great importance in archeology and anthropology . In fact, shell beads are the oldest form of jewelry known, dating back over 100,000 years. The oldest known jewelry in
120-596: The North American Busycon species and the North Atlantic Buccinum undatum ) and periwinkles including Littorina littorea . The shells of sea snails are often found washed up on beaches . Because many are attractive and durable, they have been used to make necklaces and other jewelry since prehistoric times. The shells of a few species of large sea snails within the Vetigastropoda have
135-425: The family Siphonariidae and another group of false limpets in the family Trimusculidae . Many, but not all, sea snails have an operculum . The shells of most species of sea snails are spirally coiled. Some, though, have conical shells, and these are often referred to by the common name of limpets . In one unusual family ( Juliidae ), the shell of the snail has become two hinged plates closely resembling those of
150-415: The genus Truncatella ) are sometimes considered to be sea snails and sometimes listed as land snails . Sea snails are a very large and diverse group of animals. Most snails that live in salt water respire using a gill or gills; a few species, though, have a lung, are intertidal , and are active only at low tide when they can move around in the air. These air-breathing species include false limpets in
165-531: The mollusk shell can reach. The following cladogram is an overview of the main clades of living gastropods based on the taxonomy of Bouchet & Rocroi (2005), with taxa that contain saltwater or brackish water species marked in boldface (some of the highlighted taxa consist entirely of marine species, but some of them also contain freshwater or land species.) A number of species of sea snails are harvested in aquaculture and used by humans for food, including abalone , conch , limpets , whelks (such as
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#1733093685717180-416: The shells of clams ( bivalves ) and tusk shells ( scaphopods ). Occasionally shell jewelry is made from the shells of non-marine mollusks such as the shells of land snails [1] , or the shells of freshwater mollusks. Not all shell jewelry is made from whole shells; some kinds are made from parts of shells, including the shell layer known as mother of pearl or nacre , and the "trapdoor" or operculum which
195-420: The two big parapodia (winglike flaps). Species within the genus Desmopterus include: Sea snail Determining whether some gastropods should be called sea snails is not always easy. Some species that live in brackish water (such as certain neritids ) can be listed as either freshwater snails or marine snails, and some species that live at or just above the high tide level (for example, species in
210-452: The world consists of two perforated beads made from shells of the sea snail Nassarius gibbosulus . These beads were discovered at Skhul in Israel, and were recently dated to between 100,000 and 135,000 years ago. Similar ornaments (some made from shells of Nassarius kraussianus and the bittersweet clam Glycymeris nummaria as well as from Nassarius gibbosulus ) have been discovered at
225-801: Was found; at the time the shell was used there, this site was at least 190 km away from the sea. Shell ornaments were very common during the Upper Paleolithic , from 50–40,000 years ago onwards, when they spread with modern humans to Europe and Asia. They generally take the form of perforated shells (as well as other hard organic material such as tooth , bone , antler and mammoth ivory) which are thought to have been suspended and used as jewelry. The most commonly found species are Homalopoma sanguineum , Littorina obtusata , Cyclope species, Nassarius mutabilis and Nassarius gibbosulus . Fossil shells were used alongside those of contemporary species. Some shells were stained with ochre . In Europe,
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