The class Gastropoda contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the Late Cambrian. , 721 families of gastropods are known, of which 245 are extinct and appear only in the fossil record, while 476 are currently extantwith or without a fossil record.
Gastropoda (previously known as univalves and sometimes spelled "Gasteropoda") are a major part of the phylum Mollusca, and are the most highly diversified class in the phylum, with 65,000 to 80,000 living snail and slug species. The anatomy, behavior, feeding, and reproductive adaptations of gastropods vary significantly from one clade or group to another, so stating many generalities for all gastropods is difficult.
The class Gastropoda has an extraordinary diversification of habitats. Representatives live in gardens, woodland, deserts, and on mountains; in small ditches, great rivers, and lakes; in estuaries, mudflats, the rocky intertidal, the sandy subtidal, the abyssal depths of the oceans, including the hydrothermal vents, and numerous other ecological niches, including parasitic ones.
Although the name "snail" can be, and often is, applied to all the members of this class, commonly this word means only those species with an external shell big enough that the soft parts can withdraw completely into it. Those gastropods without a shell, and those with only a very reduced or internal shell, are usually known as slugs; those with a shell into which they can partly but not completely withdraw are termed semislugs.
The marine shelled species of gastropods include species such as abalone, conches, periwinkles, whelks, and numerous other sea snails that produce seashells that are coiled in the adult stage—though in some, the coiling may not be very visible, for example in cowries. In a number of families of species, such as all the various limpets, the shell is coiled only in the larval stage, and is a simple conical structure after that. (Full article...)
The external anatomy of the soft parts of this species is similar to that of other strombid snails; the animal has an elongate snout, thin eyestalks with well-developed eyes and sensory tentacles, and a narrow, strong foot with a sickle-shaped operculum attached. Among the predators of this snail are carnivorous gastropods such as cone snails and volutes, as well as humans, who consume the soft parts in a wide variety of dishes.
In 1869 Tryon became the conservator in the malacological section. In 1879 he started the Manual of Conchology; structural and systematic; with illustrations of the species, volume 1, series 1. When he died, nine volumes of the first series had been published. After his death Henry Augustus Pilsbry continued this work for the next 47 years. (Read more...)
The image shows five different views of one shell of the sea snail species Chicoreus ramosus. This snail is a tropical species that is quite large and predatory.
The shell has a long siphonal canal and shows three varices per whorl. The varices are places where the shell temporarily stopped growing in overall length, and grew in thickness instead, creating in this case elaborate outgrowths as well as a red area on the outer surface of the columella. The shell of this species is in demand as a decorative object, and thus is part of the international shell trade.
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.