Sirenia Illiger 1811

Synonyms: Halobioidea Ameghino 1889; Herbivorae Gray 1821; Phycoceta Haeckel 1866; Sirenoidea van Beneden 1855; Sireniformes Kinman 1994; Trichechiformes Hay 1923 .

Families: 2 families with 3 genera and 5 species:

Family Dugongidae Gray 1821 (2 genera with 2 species)

Family Trichechidae Gill 1872 (1 genus with 3 species)

Discussion: Traditionally (since Illiger, 1811) the category or rank of "Order" has been used for Sirenia . In 1997 McKenna and Bell, following cladistic classification, proposed a new category – "Infraorder" for Sirenia, in the "Suborder" Tethytheria McKenna, 1975, "Order" Uranotheria McKenna and Bell, 1997. For ‘stability’ I retained the ordinal category, even though infraorder category conveys a cladistic message. For thorough index, complete synonymy, and bibliography of Sirenia, see Domning (1996).