Sea snail

This article is about shelled gastropods that live in salt water. For the fish that are also sometimes known as "snails", see Snailfish.

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.

A species of sea snail in its natural habitat: two individuals of the wentletrap Epidendrium billeeanum with a mass of egg capsules in situ on their food source, a red cup coral.

A sea snail Euthria cornea laying eggs

Definition

Anatomy

Shell

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 it can be predicted the size the mollusk shell can reach.^[1]

Taxonomy

The shell of Syrinx aruanus can be up to 91 cm long.

A 50-second video of snails (most likely Natica chemnitzi and Cerithium stercusmuscaram) feeding on the sea floor in the Gulf of California, Puerto Peñasco, Mexico.

A hermit crab occupying a shell of Acanthina punctulata has been disturbed, and has retracted into the shell, using its claws to bar the entrance in the same way the snail used its operculum.

2005 taxonomy

The following cladogram is an overview of the main clades of living gastropods based on the taxonomy of Bouchet & Rocroi (2005),^[2] 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.)

• Clade Patellogastropoda
• Clade Vetigastropoda
• Clade Cocculiniformia
• Clade Neritimorpha
  • Clade Cycloneritimorpha
• Clade Caenogastropoda
  • Informal group Architaenioglossa
  • Clade Sorbeoconcha
  • Clade Hypsogastropoda
    • Clade Littorinimorpha
    • Informal group Ptenoglossa
    • Clade Neogastropoda
• Clade Heterobranchia
  • Informal group Lower Heterobranchia
  • Informal group Opisthobranchia
    • Clade Cephalaspidea
    • Clade Thecosomata
    • Clade Gymnosomata
    • Clade Aplysiomorpha
    • Group Acochlidiacea
    • Clade Sacoglossa
    • Group Cylindrobullida
    • Clade Umbraculida
    • Clade Nudipleura
      • Clade Pleurobranchomorpha
      • Clade Nudibranchia
        • Clade Euctenidiacea
        • Clade Dexiarchia
          • Clade Pseudoeuctenidiacea
          • Clade Cladobranchia
            • Clade Euarminida
            • Clade Dendronotida
            • Clade Aeolidida
  • Informal group Pulmonata
    • Informal group Basommatophora
    • Clade Eupulmonata
      • Clade Systellommatophora
      • Clade Stylommatophora
        • Clade Elasmognatha
        • Clade Orthurethra
        • Informal group Sigmurethra

Uses

By humans

Sea snails are eaten around the world and are a food source of sterols, such as cholesterol, phytosterol, and minerals, which play an important role for human health.^[3]

Due to high calcium carbonate content, sea snail shells have potential to be used as raw material in the production of lime.^[4]

By non-human animals

See also

• Freshwater snail
• Terrestrial molluscs
• Land snail
• Sea slug