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biodiversity explorer

the web of life in southern Africa

Sirenia (manatees and dugongs)

Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Deuterostomia > Chordata > Craniata > Vertebrata (vertebrates)  > Gnathostomata (jawed vertebrates) > Teleostomi (teleost fish) > Osteichthyes (bony fish) > Class: Sarcopterygii (lobe-finned fish) > Stegocephalia (terrestrial vertebrates) > Reptiliomorpha > Amniota > Synapsida (mammal-like reptiles) > Therapsida > Theriodontia >  Cynodontia > Mammalia (mammals) > Placentalia (placental mammals) > Afrotheria > Paenungulata > Tethytheria

Modern-day representatives of this order are completely aquatic with flipper-like forelimbs and no hindlimbs.  However, fossils have been discovered in Jamaica of an extinct species Pezosiren portelli (named by Domning 2001) that had forelimbs and hindlimbs capable of being used for walking on land, although structural features relating to breathing and ballast suggest that this species probably spent most of its time in the water.

Families encountered in southern Africa

Family: Dugongidae (Dugong Dugong dugon

Contains a single species, Dugong dugon (Dugong, Sea cow, Sea pig), found along the coast of East Africa, Red Sea and N Australia. In southern Africa it is found along the Mozambican coast and the coast of northern KwaZulu-Natal.

Families not encountered in southern Africa include the Protastomidae (representatives extinct, including Prorastomus sirenoides and Pezosiren portelli both described from fossils discovered in Jamaica - see Domning [2001]) and the Trichechidae (manatees - found along tropical Atlantic coasts and adjacent rivers).


  • Domning, D.P. 2001. The earliest known fully quadripedal sirenian. Nature 413: 625-627.


Text by Hamish Robertson