Trivia Shells of the Triviidae Family

Four Trivia Shells of the Triviidae Family can be found in this website:

Phylogeny: Trivia Shells of the Triviidae Family are gastropod mollusks in the order Littorinimorpha.  This order is large and very diverse in shape including snail-like, cowry shaped, and limpet-like. Most are marine species but some are found in freshwater or on land. They all have a twisted shell and a muscular foot that is used for movement. The key characteristic is that they all exhibit torsion, which is a process where the body twists so that the anus, gills, mantle cavity, and reproductive organs all point forward. There are sixteen superfamilies in this large order. The Triviidae Family is one of three families in the superfamily Velutinoidea. The Triviidae Family is moderately large in size, with no subfamilies, sixteen genera, and around two hundred ninety-two species. Shells in this family are also commonly called Bean Cowries or Triviids.

Description: Trivia Shells are fairly small shells that are globose in shape. They closely resemble cowry shells in their structure with a low or internal spire and an aperture that runs the length of the shell. Most shells in this family have an outer lip that folds inward like a cowry. The shells may be smooth or marked with ribs that cross the top of the body whorl or stop leaving a gap. The ribs continue to the aperture generating dentition (teeth) along both sides. Trivia Shells are not particularly striking in color or pattern, though some will display color blotches, but never bands. Unlike cowries, the surface is silky, not shiny. They lack opercula. The mantle of the living mollusks is often beautifully colored. The largest species in this family reach around 1.1 cm (.4 inches) in length.

Habitat and Distribution: Trivia Shells are found attached to rocks, and within sand and mud substrates. They live in the intertidal zone and to depths exceeding 1,000 m (3,280 feet).  They are found worldwide in tropical to temperate seas. At least ten species from this family are found in Mexican waters.

Natural History: Trivia Shells are carnivores, feeding on ascidians (sea squirts). In turn they are preyed upon by shorebirds, crabs, fish, and predatory mollusks. They may be gonochoric or protandric (born male, becoming female) hermaphrodites. They reproduce sexually with internal fertilization. In some species the female protects the eggs under her foot until they hatch.