Trichechidae

Trichechidae is a family of sirenians that includes all living manatees and several extinct genera.

Miosiren is an extinct genus of manatee from the Early Miocene of southeastern England (Suffolk) and Antwerp, Belgium. thumb|left|M. canhami fossils Two species are recognized, M. canhami and M. kocki.

Potamosiren is an extinct genus of manatee from the Middle Miocene (Laventan) Honda Group of Colombia.

Anomotherium is an extinct genus of manatee that lived in the shallow seas of what is now Northern Germany. Its closest relative is Miosiren. Fossils of the genus have been found in the Bohlen and Doberg Formations of Germany.

Ribodon is an extinct genus of manatee that lived around South America (Ituzaingó Formation, then described as Entrerriana Formation, Argentina, Solimões Formation, Brazil and Urumaco Formation, Urumaco, Venezuela) during the Tortonian (Mayoan to Huayquerian in the South American land mammal ages). The type species is R. limbatus.