Puerto Rico and Florida manatees represent genetically distinct groups

The West Indian manatee ( Trichechus manatus ) populations in Florida ( T. m. latirostris ) and Puerto Rico ( T. m. manatus ) are considered distinct subspecies and are listed together as endangered under the United States Endangered Species Act. Sustained management and conservation efforts for the Florida subspecies have led to the suggested reclassification of the species to a threatened or delisted status. However, the two populations are geographically distant, morphologically distinct, and habitat degradation and boat strikes continue to threaten the Puerto Rico population. Here, 15 microsatellite markers and mitochondrial control region sequences were used to determine the relatedness of the two populations and investigate the genetic diversity and phylogeographic organization of the Puerto Rico population. Highly divergent allele frequencies were identified between Florida and Puerto Rico using microsatellite ( F ST = 0.16; R ST = 0.12 ( P