-Animals (Kingdom Animalia)

-Molluscs (Phylum Mollusca)

-Gastropods (Class Gastropoda)​​​​

-Caenogastropods (Subclass Caenogastropoda)

-Order Littorinimorpha

-Superfamily Calyptraeoidea

-Slippersnails (Family Calyptraeidae)

-Cup-and-Saucer Limpets (Genus Crucibulum)

-Crucibulum spinosum

Crucibulum spinosum is a small marine gastropod in the slippersnail family Calyptraeidae, commonly called the spiny cup-and-saucer limpet. It has a low, cone-shaped shell with a roughvexterior and a distinctive internal shelf that creates the “cup-and-saucer” structure characteristic of the genus Crucibulum. This species lives attached to hard substrates such as rocks and shells in shallow coastal waters, particularly along tropical eastern Pacific shores including Mexico. Like other members of its family, it feeds by filtering plankton from the water and remains firmly cemented in place as an adult.