Metaxytherium
Metaxytherium (binomen a De Christol, 1844) est exstincta sireniorum familia.

Systema taxinomicum Animalis 
 Imperium: Eucaryota
 Regnum: Animalia
 Gradus: Metazoa
 Subgradus: Eumetazoa
 Subregnum: Bilateria
 Infraregnum: Eucoelomata
 Supraphylum: Deuterostomia
 Infraphylum: Chordonia
 Phylum: Chordata
 Subphylum: Vertebrata
 Infraphylum: Gnathostomata
 Supraclassis: Tetrapoda
 Infraclassis: Amniota
 Ramus: Mammaliaformes
 Classis: Mammalia
 Subclassis: Theriiformes
 Infraclassis: Holotheria
 Supralegion: Trechnotheria
 Legion: Cladotheria
 Sublegion: Zatheria
 Infralegion: Tribosphenida
 Supracohort: Theria
 Cohort: Placentalia
 Superordo: Afrotheria
 Ordo: Sirenia
 Familia: Dugongidae
 Subfamilia: Hydrodamalinae
 Genus: Metaxytherium (De Christol, 1844)

Species 
 Metaxytherium aquitaniae (Piller, 1987) 
 Metaxytherium arctodites (Aranda-Manteca & Barnes & Domning, 1994) 
 Metaxytherium beaumontii (De Christol, 1844) 
 Metaxytherium calvertense (Kellogg, 1966) 
 Metaxytherium crataegense (Simpson, 1932) 
 Metaxytherium floridanum (Hay, 1922) 
 Metaxytherium krahuletzi (Depéret, 1895) 
 Metaxytherium lovisati (Capellini, 1986) 
 Metaxytherium medium (Desmarest, 1822) 
 Metaxytherium meyeri (Abel, 1904) 
 Metaxytherium serresii (Gervais, 1847) 
 Metaxytherium subapennium (Bruno, 1839)

Sirenia