Desmostylia

Common card · No. 418176

Desmostylia (from Ancient Greek δεσμά (desmá), meaning "bundle", and στῦλος (stûlos), meaning "pillar") is an extinct order of aquatic mammals native to the North Pacific from the Early Oligocene (Rupelian) to the Late Miocene (Tortonian) from 33.9 to 7.2 or 5.3 Ma. However, phylogenetic models suggests the order first appeared during Middle Eocene between 47 and 39 Ma. Desmostylians are the only known extinct order of marine mammals. Their taxonomic placement within Placentalia is subject to considerable debate. The Desmostylia, was traditionally assigned to the afrotherian clade Tethytheria, together with Sirenia (manatees and dugongs) and Proboscidea (elephants and their extinct relatives) and the extinct Embrithopoda. The relationship between the Desmostylia and the other orders within the Tethytheria has been disputed; if the common ancestor of all tethytheres was semiaquatic, the Proboscidea became secondarily terrestrial; alternatively, the Desmostylia and Sirenia could have evolved...

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