Pliocene sirenians

Metaxytherium is an extinct genus of dugong that lived from the Oligocene until the end of the Pliocene. Fossil remains have been found in Africa, Europe, North America and South America. Generally marine seagrass specialists, they inhabited the warm and shallow waters of the Paratethys, Mediterranean, Caribbean Sea and Pacific coastline. American species of Metaxytherium are considered to be ancestral to the North Pacific family Hydrodamalinae, which includes the giant Steller's sea cow.

Dusisiren is an extinct genus of dugong related to the Steller's sea cow that lived in the North Pacific during the Neogene.

species of extinct mammal

Corystosiren is an extinct genus of dugongid sirenian mammal which existed in the waters of the Caribbean Basin during the Early Pliocene. Fossils have been found in the Yucatán Peninsula, Mexico, and Florida.