Gastropod Shells (220)

Gould’s Bubble, Bulla gouldiana. A representative Gastropod from the Bubble Shell or Bullidae Family.

The Gastropoda class of Gastropods is one of ten classes within the superclass Aplacophora, and this superclass is the only superclass within the phylum Mollusca. Gastropods are the second largest class of living animals, with the Insecta class being first. Approximately eighty percent of mollusks are in this class. The gastropoda class is complex taxonomically and the taxonomic systems have undergone revision a few times in recent decades. Depending on the system and the sources, there are around four hundred ten to four hundred eighty extant families in this class. Again, depending on the source, there are forty thousand to eighty thousand extant species of Gastropods. Gastropods include animals with snail-like shells, flattened shells (limpets, abalone), or no shell at all (slugs).

The name Gastropod means “stomach-foot” and refers to the appearance that these animals are crawling on their stomachs. Actually, they are crawling on a muscular foot that runs the length of their body. The foot holds them to the substrate, and allows them to move over the substrate. The animal is covered by a mantle. The mantle secretes the shell for shelled species. Gastropods have a fairly well-developed head compared to shells in the class Bivalvia or Polyplacophora.  The head includes a mouth and sensory structures such as tentacles or eyes. All gastropods have a radula, which is a file-like organ used for scraping or drilling to obtain food. Shelled gastropods have a single shell (they were formerly known as univalves), which twists, even if only at the apex (protoconch). All gastropod shells have an aperture, which is where the animal extends from the shell. The aperture may be as big as the shell diameter, like a limpet, or small like a snail or slit-like in a cone shell or cowry. Gastropods differ greatly in shape, exterior sculpture and texture, color, and size. Gastropod larva start life bilaterally symmetrical. Very quickly they twist so the the organs point in the opposite direction from the head. This process, called torsion, begins their asymmetrical spiraled existence.

Gastropods are found in practically every ecosystem on Earth. They may be terrestrial, freshwater, or marine species. Marine species may be found on soft substrates like sand or mud, hard substrates like rock or coral, plants, or on the surface of the ocean. They are generally free to move from place to place. They are found from the high intertidal zone to the deepest ocean basins. They are found worldwide from tropical to polar seas. Gastropods are diverse in the feeding behavior. They may be herbivorous grazers, opportunistic browsers, scavengers, detritivores, or carnivorous predators.

 Gastropods have long been a part of the diet of coastal human populations. They continue to be an important food source in many regions, with some being considered a delicacy. Many Gastropod species are harvested and farmed commercially. Some gastropod shells are beautiful in color, texture, and/or form, and are highly sought by shell collectors.

To provide you with easy access to the 220 Gastropods currently presented in this website, each individual shell has its own stand-alone page which can be found via links within the alphabetical indexes presented by Common Name, Genus and Species and Family provided immediately below. Each shell found in this website has been placed in its specific family, along with its fellow family members, with support information provided for its family as well as a link in the photo caption that will take you to the shell page that has additional photographs and shell specific information.

Gastropods (220) – Alphabetical Index by Common Names
Gastropods (220) – Alphabetical Index by Genus and Species
Gastropod Families (49) – Alphabetical Index by Common Name
Gastropod Families (49) – Alphabetical Index by Scientific Name