The Mosasaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "mosasaurines" and their fossils have been recovered from every continent except for South America. Though represented by relatively small forms throughout the Turonian and Santonian, such as Clidastes, the lineage diversified during the Campanian and had by the Maastrichtian grown into the most diverse and species-rich mosasaur subfamily.