See text Cerion is a genus of small to medium-sized tropical air-breathing land snails, terrestrial pulmonate gastropods in the family Cerionidae, noted for its extreme morphological diversity.

[7][8][4][5][1] Cerionid species inhabit nearshore terrestrial vegetation, usually within a few hundred meters of the shore but occasionally further inland, up to a kilometer away in areas influenced by salt spray.

The genus represents one of the most challenging groups in pulmonate mollusk classification, often described as a "taxonomic morass" due to its extreme morphological diversity and the frequent hybridization at geographic contact points.

Recent molecular studies using 28S rRNA sequence data have supported the classification of Cerionidae within the new superfamily Urocoptoidea, which also includes the North American and circum-Caribbean Urocoptidae.

[6] Paleontological studies suggest that the genus, possibly originating from the late Cretaceous of North America and subsequently diversifying in the Caribbean through a series of vicariance and dispersal events.

The evolutionary trajectory of Cerion lineages is marked by significant morphological change, potentially driven by hybridization and geographical isolation events during glacial and interglacial periods.