Portal:Gastropods/Selected article/13

Juliidae, common name the bivalved gastropods, is a family of minute sea snails, marine gastropod mollusks or micromollusks in the superfamily Oxynooidea, an opisthobranch group.

This family of snails is extremely unusual in that their shells consist of two separate hinged pieces or valves, which are joined by a ligament, and which look nothing like a normal snail shell, but instead look almost exactly like the two hinged valves of a clam, a bivalve mollusk, a very different class of animals.

In the past the Juliidae were known only from fossil shells, and not surprisingly these fossils were therefore interpreted as being the shells of bivalves. Julia, which is the type genus of the family, was named in 1862 by Augustus Addison Gould, who described it as a bivalve genus. Julliidae are known from the Eocene period to the Recent, but they probably first appeared during the Paleocene. (Read more...)