What is "umbraculoidea"

Umbraculoidea is a superfamily of unusual false limpets with a thin soft patelliform shell, marine gastropod molluscs in the clade Umbraculida, within the clade Euopisthobranchia.

There are two families in this superfamily, which is listed as the only superfamily in the clade Umbraculida within the informal group Opisthobranchia in the taxonomy of Bouchet & Rocroi (2005).