Comments: One of only four living species in the order Sirenia; the two other manatee species occur along the coast of West Africa (T. senegalensis) and in rivers of northeastern South America (T. inunguis). The other living sirenian, Dugong dugong, occurs in tropical bays and estuaries of the Indian and western Pacific oceans.
García-Rodríguez et al. (1998) examined range-wide phylogeography based on mtDNA variation in eight locations from Florida south to coastal Brazil. They detected three distinctive mtDNA lineages, corresponding approximately to: (1) Florida and the West Indies (Puerto Rico, Hispaniola); (2) Gulf of Mexico to the Caribbean rivers of South America (Mexico, Colombia, Venezuela); and (3) northeast Atlantic coast of South America (Guyana, Brazil). These lineages, which exhibit strong but incomplete geographical partitioning, are not concordant with previously recognized subspecies designations.