| Despite morphological and paleontological analysis to date, there is little or no agreement on how to arrange the various mammalian orders into superordinal clades. This study examined mitochondrial DNA (mtDNA) sequences of cytochrome b, the tRNAs threonine and proline, and the control region for the African and the Asian elephants (Loxodonta africana and Elephas maximus), the rock hyrax (Provocavia capensis), the aardvark (Orycteropus afer), and the dugong ( Dugong dugon). Phylogenetic analysis of these sequences, in addition to those of the three extant manatee species (Trichechus manatus, Trichechus inunguis, and Trichechus senegalensis), is presented as an argument in support of the proposed subungulate (or paenungulate) clade designation. This designation groups all of these animals together as a phyletic lineage derived from a single common ancestoral species.; Phylogenetic analysis of mtDNA sequence from the West Indian and as Amazonian manatees did not readily align with the currently accepted, morphologically based, taxonomy of Trichechus. My evidence shows four primary branches, three in T. manatus, one in T. inunguis . My data also indicates that hybridization between these two presumptive species has occurred, suggesting a shared maternal ancestor more recently than was previously suspected.; All populations of the three extant species of manatee are diminished relative to historic levels. As a result, the long-term survival of these species is in peril. This study presents sequence data for all extant species of the manatee. DNA sequence analysis was used to evaluate the distribution of genetic variability among the three species of extant manatees, between subspecies of the West Indian manatee (T. m. manatus and T. m. latirostrus), and among populations of the West African manatee. DNA analysis is an essential step in developing and implementing a management program for endangered species as it can provide a determination of existing genetic variability, as well as qualitative signals of genetic change within populations in response to management actions.; This study provided the first report of West African manatee DNA sequence. The findings are currently being used in the implementation of the International Union for the Conservation of Nature and Natural Resources' West African Manatee Recovery Plan. |
