Family Dugongidae - Dugong (1 living species in 1 genus)
There is only 1 living species in the family Dugongidae. The other recent member, Steller's sea cow (Hydrodamalis gigas), has been extinct since 1768. The dugong is tropical and subtropical, but Steller's sea cow was an inhabitant of cold temperate to subarctic waters. In members of this family, the flattened tail is expanded into flukes, similar to those of cetaceans. Other characteristics include a rostrum that is deflected downwards, the presence of erupted tusks in males (dugong only; Steller's sea cow had no teeth), a more streamlined body than those of manatees, and the absence of nails on the flippers.
Genus Dugong containing 1 species:
Dugong dugon (Dugong)