are a class
of animals which have no backbone
. In most but not all cases gastropods have a shell
, which is created by the mantle
. Gastropods are commonly known as snails
. They live in the oceans, on land and in freshwater.
This taxonomic class of invertebrate animals with the scientific name Gastropoda is the largest and most successful class within the mollusks, having 60,000–75,000 named living species, and being second only to the insects in terms of diversity and in terms of the number of named species within one class of animals. Living species of gastropods range in size from adult animals that are less than one millimeter (0.039 in) in length, to a few species that are almost a meter (39.4 in) in length.
Scientists who study gastropods (or other mollusks) are known as malacologists. 2,400 years ago, Aristotle, in his History of Animals, wrote about the sea snails from which the dye Tyrian purple is extracted; the genus Murex still bears the name he used. Many gastropods are important food sources, others have human relevance in other ways, ranging from their shells being used as a source of mother of pearl through to their being vectors for several diseases.
Aquamarine or sea green is used on this portal because gastropods first evolved in the oceans, colonized both land and freshwater habitats, and need the presence of water or water vapor in order to be active. The image which is currently the icon for the gastropod portal shows an individual of Helix pomatia, an air-breathing land snail which is well known to gourmets in the Western world because it is one of the European species that is eaten as escargot.
A love dart
is a hard, sharp, calcareous
dart which some hermaphroditic land snails
create. Love darts are made in sexually mature animals only, and are used as part of the sequence of events during courtship
before actual mating
Prior to copulation, each of the two snails (or slugs) attempt to "shoot" one or more darts into the other snail (or slug). There is no organ to receive the dart; this action is more analogous to a stabbing, or to being shot with an arrow. The dart does not fly through the air to reach its target however; instead it is fired as a contact shot.
The love dart is emphatically not a penial stylet (in other words this is not an accessory organ for sperm transfer). The exchange of sperm between each of the two land snails is a completely separate part of the mating progression. Nevertheless, recent research shows that use of the dart can strongly favor the reproductive outcome for the snail that is able to lodge a dart first in its partner. This is because mucus on the dart introduces a hormone-like substance that allows far more of its sperm to survive. (Read more...)
Stephen Jay Gould (September 10, 1941 – May 20, 2002) was an American paleontologist, evolutionary biologist and historian of science. He was also one of the most influential and widely read writers of popular science of his generation. Gould spent most of his career teaching at Harvard University and working at the American Museum of Natural History in New York City. In the latter years of his life, Gould also taught biology and evolution at New York University near his home in SoHo.
Gould's greatest contribution to science was the theory of punctuated equilibrium, which he developed with Niles Eldredge in 1972. Most of Gould's empirical research was based on the land snails Poecilozonites and Cerion, which are endemic to Bermuda and the Caribbean area respectively.
Gould also contributed to evolutionary developmental biology, and has received wide praise for his book Ontogeny and Phylogeny. In evolutionary theory he opposed strict selectionism, sociobiology as applied to humans, and evolutionary psychology. He campaigned against creationism and proposed that science and religion should be considered two distinct fields, or "magisteria", whose authorities do not overlap. (Read more...)
... that Acmella nana (shell pictured) is the smallest known land snail?
... that the fragile shell of the glassy nautilus Carinaria cristata (pictured) was at one time considered to be worth more than its weight in gold?
... that Spurilla neapolitana (pictured) defends itself with stinging cells derived from the sea anemones it eats?
... that Pupilla pratensis (shell pictured) has long been neglected in the malacological literature?
... that there are 12 endemic species of freshwater snails in Lake Skadar (map pictured)?
... that the land snail Balea sarsii (shell pictured) has been overlooked for a long time?
... that the land snail Vertigo ultimathule (shell pictured) is endemic to the northenmost part of Scandinavia?
... that flashes of light emitted by the sea snail Hinea brasiliana (shell pictured) may act as a "burglar alarm"?
- ... that Candidula arganica, a snail found in the north of the Iberian Peninsula, lives primarily in meadows?
- ... that Candidula spadae, a snail native to Central Italy, is at risk in part because of tourist activities?
... that the subterranean freshwater snail Hauffenia sp. from Slovakia (shell pictured) has been an undescribed species since the 1980s?
... that land snails of the genus Abbottella (Abbottella calliotropis shell pictured) live on the islands of Hispaniola and Cuba?
... that the snail Tonna galea (pictured) is one of very few species of prosobranch gastropods that are luminescent?
... that the land snail Notodiscus hookeri (shell pictured) has unique shell structure among all gastropods?
... that the microscopic cave snail Zospeum tholussum (pictured) is so slow that in a week's time it may only move a few millimeters or centimeters in circles?
... that the land snail Omalonyx convexus (pictured) can also be found submerged among macrophytes?
... that the malacologist S. Peter Dance said the shell of Pterynotus loebbeckei, (pictured), was the "most exquisite natural object" he had ever seen?
... that the only brackish-water pachychilid species, Faunus ater (shell pictured), has a shell that is unique among all the Cerithioidea?
... that the owl limpet (pictured) maintains a small meadow of algal turf for its own exclusive use?
- 16 July 2010: A new subfamily is established within the Chondrinidae.
- A list of new Wikipedia articles about gastropods, including those that simply mention the words snail, slug, conch, etc. A bot creates this list, usually every three days.
The shell of the Venus comb murex Murex pecten has an extremely long siphonal canal. The shell has over one hundred spines, which provide protection from predation, and prevent the snail from sinking in the soft mud. This image shows three views of one shell: an apertural view on the right, abapertural view on the left, and apical view at the bottom.
- Gastropoda, snail, slug, land snail, freshwater snail, sea snail, sea slug
- Gastropod shell, operculum, radula, love dart, clausilium
- Digestive system of gastropods, respiratory system of gastropods, circulatory system of gastropods, excretory system of gastropods, sensory organs of gastropods, nervous system of gastropods, reproductive system of gastropods
- Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), and also, changes in the taxonomy of gastropods since 2005
- Gastropods with significant positive human impact
- Gastropods with significant negative human impact
Categories about gastropods:
Request to editors: please do not create any more categories of gastropods by country. Instead create list articles, article with a list of the marine or non-marine gastropods of whichever country or area you are interested in. We would also like to empty and delete the two remaining country categories we have, adding that information to list articles instead. Thank you.