The order Sirenia contains three living species of Manatee (Trichechidae) and one species of Dugong (Family Dugongidae). The Florida Manatee( Trichechus manatus latirostris) is one subspecies of the West Indian Manatee. The Antilian Manatee (Trichechus manatus manatus) is the other West Indian subspecies. West Indian Manatees occupy coastal and estuarine waters throughout the Caribbean region. The Amazonian Manatee (Trichechus ininguis) lives entirely in the Amazon river and its tributaries. A third species of Manatee, the West African, (Trichechus senagalensis) occupies the coastal waterways of the West African Continent. Dugongs (Dugong dugon) occupy the marine coasts of east Africa, the Indian subcontinent, Malaysia, Indonesia and northern Australia.

A fifth, and largest, Sirenian of recent times, the Stellar Sea Cow (Hydrodamalis gigas), was also a member of the family Dugongidae. These enormous sirenians had evolved further to occupy the colder waters along the shores of the eastern Pacific ocean. These animals survived off the Aleutian islands until 1872, when the last animal of this species was killed for food , 28 years after being first sighted. Although there is only one living species of dugong, ancestors resembling them were diverse and widely distributed in the fossil record. Sirenians were most diverse in the Miocene (5-25 mya) when tropical conditions were widespread. The most widespread genus was Metaxytherium, which is considered ancestral to a subfamily of dugongids which included the Stellar Sea Cow. Metaxytherium lived world wide throughout the Mediterranean, Caribbean and western Pacific (SA & NA). Manatees and Dugongs appeared to have separated about 40 mya. (The conclusions here were gleaned from the many published studies of Dr. Daryl P. Domning)

(Poster above provided by Save the Manatee Club)

Family Trichechidae


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